JP2003517631A - Improvement of Flexible Modular Compact Optical Fiber Switch - Google Patents

Abstract

(57) Abstract: An optical fiber switching module (100) for receiving and fixing an end (104) of an optical fiber (106) is provided in an optical fiber switch (400). The module (100) includes a number of V-shaped arrayed reflected light beam deflectors (172) that can be selected as a pair and couple the light beam (108) between a pair of optical fibers (106). Further, the module (100) generates a direction signal indicating the direction from each deflector (172). A port card (406) is also provided to provide a drive signal to the module (100) for orienting the at least one deflector (172). Further, the port card (406) receives the direction signal generated by the deflector (172) together with the coordinates specifying the direction of the deflector (172). The port card (406) compares the received coordinates with the direction signal received from the deflector (172), adjusts the drive signal supplied to the module (100), and there is a difference between the received coordinates and the direction signal. If so, reduce it. The switch (400) also employs optical alignment to accurately orient the deflector (172) pair that couples the light beam (108) between the optical fibers.

Description

Detailed Description of the Invention

[0001]

[Industrial applications]

The present invention relates generally to the technical field of optical fibers, and more particularly to free space / reflecting NxN optical fiber switches.

[0002]

[Prior art]

Although the dramatic increase in telecommunications seen in recent years can be attributed largely to Internet communications, it has required the rapid introduction and commercial adaptation of numerous technological innovations in fiber optic telephone communications. For example, fiber telecommunications systems have recently been introduced and may be installed to transmit digital communications simultaneously on 4, 16, 32, 64 or 128 different optical wavelengths propagating along a single optical fiber. I am trying.
Although multiwavelength fiber optic telecommunications dramatically increases the bandwidth of a single optical fiber, this bandwidth increase is only available at both ends of the optical fiber, for example between two towns. When the light sent to one end of the optical fiber reaches the other end of this optical fiber, the light received at one end of the optical fiber is transferred to several different optical fibers in order to carry it to another destination. There is currently no highly adaptable, modular, compact NxN fiber optic switch that can automatically send to a chosen one of these.

Historically, when telecommunications were transmitted by electrical signals over a pair of copper conductors, a person, formerly called a telephone operator, sat in a manually-operated switch and was fitted with a pair of plugs attached to it. A telephone call received on a copper conductor was manually connected to another pair of copper conductors mounted in a socket to complete the telephone line. The task of a switch to manually interconnect a pair of conductors coming from two phones to set up a circuit phone is first called a crossbar switch, which automates the switch's manual task in response to a telephone dial turn signal. Replaced by electromechanical device. This electromechanical crossbar switch for electrical telecommunications has been replaced by an electronic switching system during the last 40 years.

Currently, there are fiber optic telephone communication switches for fiber optic telephone communications that perform similar or identical functions to those performed by telecommunications crossbar switches and electronic switching systems. But the fiber optic switches available today are far from ideal. That is, the existing optical fiber telecommunications technology does not have a switch that can perform the same optical communication function as many electronic switching systems do for many optical fibers.

In one approach used to provide a 256 × 256 switch for fiber optic telecommunications, a light beam received from an incoming fiber optic is first converted to an electrical signal that is transmitted through an electronic switching network. The output signal from the electronic switching network is then used to generate a second beam of light that enters the output optical fiber. As people familiar with electronics and fiber optic telecommunications recognize, the above approach of providing a 256x256 fiber optic switch is physically very large, requires very high speed electronic signal processing, and is extremely expensive. It will be

[0006] Various attempts have been made to assemble optical fiber switches that directly couple (connect) a light beam from one optical fiber to another optical fiber in an attempt to avoid complex electronic circuits and conversion between optical and electrical signals. . One of the earliest attempts to provide fiber optic switches (switches) was to mimic the behavior of a switch mechanically with fiber optics and not with copper conductors. In U.S. Pat. No. 4,886,335 "Optical Fiber Switch System" (issued December 12, 1989), a ferrule is attached to the end of an optical fiber and a conveyor for moving the ferrule is provided. The conveyor moves the ferrule to the selected adapter and inserts the ferrule into the coupler / decoupler on the adapter. After the ferrule is inserted into the coupler / decoupler, light passes between the optical fiber held by the ferrule and the optical fiber fixed to the adapter.

US Pat. No. 5,864,463 “Small 1 × N electromechanical optical switch and variable attenuator” (issued on Jan. 26, 1999, hereinafter referred to as 463 patent) selectively uses one optical fiber and one of many optical fibers. Other mechanical systems for interlocking are described. The selective coupling of one optical fiber to one of a number of optical fibers described in this patent involves mechanically moving the ends of one optical fiber along a linear array of the ends of another optical fiber. Made by. A 1 × N switch uses a mechanical actuator to coarsely align the end of this one optical fiber to a selected one of the other optical fibers within 10 μm. A 1xN switch uses the light reflected back to the moving optical fiber from the immediately adjacent end of the selected optical fiber and then accurately aligns the end of the input optical fiber with the other optical fiber. US Pat. No. 5,699,463
In the "Mechanical Fiber Optic Switch" (issued December 16, 1997), the end of one optical fiber is aligned with one of several other optical fibers as a linear array, but two optical fibers are used. A lens is interposed between.

In US Pat. No. 5,524,153 “Optical Fiber Switching System and Method of Using It” (issued June 4, 1996, hereinafter 153 patent), two optically opposite groups of optical fiber switching units are close to each other. It is arranged. Each switching unit can align any one of its optical fibers with any one of the optically opposite switching unit groups. Within the switching unit, one end of each optical fiber is positioned proximate to the beam forming lens and is received by a biaxial piezoelectric bender (bending machine). A biaxial piezoelectric bender can bend a fiber such that the light emitted from this fiber is directed to a particular optical fiber of an optically opposite switching unit group. Pulsed light generated by a radiation (electromagnetic radiation) emitting device (RED) associated with each optical fiber travels from the fiber toward a selected optical fiber of the opposite group. The pulsed light from the RED received by the opposite group of selected optical fibers is processed to produce a signal,
This signal is fed back to the piezoelectric bender and the light from the optical fiber is directly
It is oriented in the direction of the selected optical fiber.

Optical switches have also been proposed that do not mechanically direct the light beam from one optical fiber to another by moving or bending one or both optical fibers. It uses a microfabricated moving mirror to couple the light emitted from an input optical fiber to an output optical fiber. February 1999-
A paper submitted to the OFC / IOOC held on the 26th describes a device that can be used to fabricate a three-stage fully non-blocking optical fiber switch as shown schematically in FIG. In the moving mirror array used in this optical fiber switch, each polysilicon mirror can selectively reflect light at an angle of 90 °. In the optical fiber switch according to this proposal, rows 52a _i (i = 1, 2, ... 32) and rows 52b _k (k = 1, 2, ...) Of a relatively small 32 _× 64 optical switching array.
· 32) receives light from the input optical fiber 54a _n of 32, are sent to the output optical fiber 54b _n of 32. 32 groups of 64 optical fibers 56a _{1, m} and 56b _{1, m} are provided for each 32x64 optical switching array 52a _i , 52b _k and 32x3.
It carries light with one of the two optical switching arrays 58 _j (j = 1, 2, ... 64).

It is immediately apparent that the optical fiber switch shown in FIG. 1 is complex. For example, a 1024x1024 fiber optic switch constructed according to this proposal would be:
4096 individual optical fibers are required to interconnect the optical switching arrays 52a _i and 52b _k with the 32 _× 32 optical switching array 58 _j .
Furthermore, 32 × 64 optical switching arrays 52a _i and 52b _k and 32 _× 32
Each optical switching array 58 _j requires a total of 196,608 micromachined mirrors.

The proposed polysilicon mirror for the fiber optic switch shown in FIG. 1 is not optically flat, but bent. Moreover, the heat dissipation of such mirrors is sufficient to switch light of a single 0.3 mW wavelength, or in some cases several wavelengths, even though such mirrors switch 10 or 20 of such wavelengths. ,Can not. But, as mentioned above, fiber optic telecommunications is now trying to send more than 40 wavelengths on a single optical fiber, and will soon, if not already, be sending hundreds of wavelengths. Each output is 0 instead of single wavelength light
． If one optical fiber carries 3 mW of 300 different wavelengths of light, the proposed polysilicon mirror for this optical fiber switch will have an output of 100 mW. Given that the polysilicon mirror reflects 98.5% of this light, the mirror must absorb the rest, ie 1.5 mW of power. Absorbing an output of 1.5 mW would heat the thermally non-conductive polysilicon mirror to an unsuitable temperature that would further degrade mirror flatness.

US Pat. No. 4,365,863, “Optical switch for ultra-large number of channels” (1982, 1
Published February 28, the following 863 patent) describes an optical fiber in which two end portions of a regular arrangement of optically opposed end portions are arranged in parallel. The space between the two arrays contains an optical switching system with a propagation mode mode converter associated with each fiber of each array. The mode converter converts light from the constrained propagation mode in the glass filament to the directional propagation mode. In its simplest form, the transducer consists essentially of an optical lens whose focal point lies approximately at the end of the corresponding fiber.

In the optical switching system of the 863 patent, a light beam deflector is associated with each fiber of the two arrays. Either one of the arrays
It sends a beam of light to the associated deflector. The deflector receives the light beam from the mode converter and redirects the light to any one of the deflectors associated with the other array of optical fibers. The deflector or the deflector receiving the beam redirects light to its associated mode converter. The optical beam deflector may be of any type.
To do. The 863 patent specifically discloses the use of either a mechano-optical device operating on the diasporometer principle or an acousto-optical deflector based on photon interactions in a crystalline medium.

Each light beam deflector in the 863 patent is controlled by an interface control driven by a logic circuit. A deflector is associated with each light beam and derives data corresponding to the address of the optical fiber in the respective array from the signal carried by the beam. The logic circuit group is a central processing unit that controls all the functions of the switching system. Each detector in the 863 patent comprises, for example, a semi-transparent mirror that samples the corresponding light beam, an optoelectronic device that converts the sample of the light beam into an electrical signal, and a device that decodes the electrical signal to derive address data for the optical fiber. You can

The technical document “A Silicon Light Modulator”, Kar
i Gustafsson & Berti Hoek, the Journal
l of Physics E.I. Scientific Instrument
s, pp. 680-85 (hereinafter Gustafsson et al document) describes an array of four one-dimensional torsion scanners micromachined from an epitaxial layer of a silicon substrate. It is this G that electrostatically excites the torsion scanner.
It is described in the ustafsson document. This document reports that such operation of a twist scanner is used in fiber optic switches and modulators to couple light between a pair of immediately adjacent optical fibers.

[0016]

[Problems to be Solved by the Invention]

The present invention seeks to provide an optical fiber switch that is capable of simultaneously coupling (connecting) incoming beams of light carried in over 1000 individual optical fibers to over 1000 outgoing optical fibers. It is an object of the present invention to provide a simpler optical fiber switch that can switch between multiple incoming and outgoing beams of light carried in an optical fiber. It is another object of the present invention to provide an efficient optical fiber switch that can switch between multiple incoming and outgoing beams of light carried in an optical fiber. Another object of the present invention is to provide an optical fiber switch with low crosstalk between communication channels. Another object of the present invention is to provide an optical fiber switch with low crosstalk between communication channels during switching. Another object of the present invention is to provide an optical fiber switch with extremely high reliability. Another object of the present invention is to provide an optical fiber switch that does not show variations. Another object of the present invention is to provide a polarization-independent optical fiber switch. Another object of the invention is to provide a completely transparent optical fiber switch. Another object of the present invention is to provide an optical fiber switch that does not limit the bit rate (bit transmission rate) of optical fiber communication through the switch.

[0017]

[Means for Solving the Problems]

Briefly, the invention is a fiber optic switching module suitable for use in a fiber optic switch and comprising a first group and a second group of fiber optic receivers. These two groups of optical fiber receivers are located at both ends of the free space optical path and are separated from each other. Each fiber optic receiver is adapted to receive and secure an end of an optical fiber. This fiber optic switching module also has a lens,
One of them is fixed to each of the first and second groups of optical fiber receivers so as to face the lens fixed thereto. Each lens is suitable for receiving a light beam that may be emitted from opposite ends of the optical fiber and for emitting a quasi-parallel light beam in the optical path of the fiber optic switching module.

The fiber optic switching module also includes a first set and a second set of reflective light beam deflectors arranged in a V shape in the optical path between the groups of fiber optic receivers. Each of the light beam deflectors has: 1. Associated with one of the lenses fixed to each of the fiber optic receivers, 2. a quasi-parallel light beam emissible from the companion lens is positioned such that it strikes the light beam deflector and is reflected; To reflect a quasi-parallel light beam, which is energized and directed by a drive signal supplied to the fiber optic switching module, and which can be emitted from the companion lens, such that it reflects off a selected light beam deflector. To do. The fiber optic switching module further comprises a mirror disposed along the optical path between the sets of light beam deflectors impinged by the quasi-parallel light beam.

By selecting and orienting the pair of light beam deflectors arranged as described above by the drive signal supplied thereto, one can be fixed to any one of the optical fiber receivers, and the other can be fixed to the optical fiber receiver. An optical coupling of at least one quasi-parallel light beam can be made between a pair of lenses, which can be fixed to another one of the receivers.

The above and other features, objects and advantages will be apparent and apparent to those skilled in the art from the following detailed description of the preferred embodiments illustrated in the various drawing figures.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Free Space Convergent Beam Double-Bounce Reflective Switching Module Referring to FIG. 2, a trapezoidal free space converging (convergent beam) NxN reflective switching module according to the present invention is designated by the general reference numeral 100 and the light propagating therethrough. Shows ray tracing of a beam. The NxN reflective switching module 100 has sides 102a and 102b that are spaced apart from each other at both ends of the C-shaped free space optical path. Although other geometrical relationships between sides 102a and 102b are possible for other shapes of NxN reflection switching module 100 as described below, the NxN reflection shown in FIG. 2 with a C-shaped free space optical path. For embodiments of switching module 100, sides 102a and 102b are preferably coplanar. Side 102
Both a and side 102b are adapted to receive and secure N, for example 1152, ends of optical fiber 106. N optical fibers have 3 columns
In a rectangular array of 6, each column is arranged to accommodate 32 optical fibers. Along the optical path between the sides 102a and 102b, the end 10 of each optical fiber 106 is
The lens 112 is arranged immediately adjacent to No. 4. Each lens 112 has an end 104 of the associated optical fiber 106 with respect to an end 104 of the optical fiber 106 with which it is associated.
A quasi-collimated beam is generated from the emitted light, which forms side 102a and side 102b.
It is arranged so as to propagate along the optical path between them.

FIG. 3 diagrammatically illustrates one light beam 108 from one optical fiber 106 propagating from side 102a to side 102b, or vice versa. The lens 112 is a microlens having a focal length of 2.0 to 12.0 mm with respect to the wavelength of light normally used for single mode optical fiber communication. Such a lens 112
Is preferably about 1.5 mm in diameter and has a length of 5 between sides 102a and 102b.
It produces a quasi-parallel beam that propagates along a route of 00-900 mm. Since the NxN reflection switching module 100 preferably uses the maximum relay length of the lens 112, the end 104 of each optical fiber 106 is positioned within the commercial distance of the lens 112 plus the Rayleigh range of the light beam 108 emitted from the optical fiber 106.
Therefore, a displacement of the end 104 of the optical fiber 106 by a few microns along the axis of the lens 112 has a negligible effect in the direction in which the quasi-parallel beam of maximum relay length propagates between the sides 102a and 102b. . Generally, the exit angle of a quasi-parallel collimated beam of maximum relay length from lens 112 will be a fraction of 1 milliradian, or 0.001 radian. As described in detail below, the end 10 of the optical fiber 106.
Even if there is a misalignment of the quasi-parallel parallel beam with the maximum relay length due to the misalignment between the lens 4 and the lens 112, it is easily accommodated by making the reflecting surface of the beam sufficiently large.

After passing through the companion lens 112, the light beam 108 emitted from the end 104 of the optical fiber 106 is represented by the dashed line in FIG.
The reflected light is reflected by the mirror surface 116a or 116b associated with the six pairs and exits. The mirror surface 116, described in detail below, is described in US Pat. No. 56297, which is hereby incorporated by reference.
Preferably, a two-dimensional torsion scanner of the same type as that described in US Pat. The NxN reflection switching module 100 has a side 102.
There are two sets 118a and 118b of mirror surfaces 116 respectively disposed between lenses 112 along the optical path between a and side 102b. Each set 118a, 118b is provided with a number of individual and independent mirror surfaces 116, each supported by a pair of gimbals, such that each mirror surface 116 is rotatable about two non-parallel axes. .. The number of mirror surfaces 116 depends on the optical fiber 106 and the side 102a or the side 102.
It is equal to the number N of lenses 112 closest to b. After reflecting out of the mirror surface 116a or 116b, the light beam 108 propagating between the sets 118a and 118b of FIG. 2 then reflects out of the selected one of the mirror surfaces 116b or 116a, and the side 10
Along the C-shaped optical path between 2a and side 102b, through one of the lenses 112 on the far side 102b or 102a, is incident on the optical fiber 106 associated with that particular lens 112.

4a and 4b show ray tracings of a light beam propagating through another embodiment, a rectangular focusing NxN reflection switching module 100. The rectangular converging NxN reflection switching module 100 shown in Figures 4a and 4b uses a horizontally elongated Z-shaped free space optical path. In this figure, side 102a and curved surface set 1
18a, between curved surface set 118a and curved surface set 118b, and between curved surface set 1
One of ordinary skill in the art will appreciate that although the distances between 18b and side 102b are equal, these distances need not be equal. Further, those skilled in the art will recognize that the bends in sets 118a and 118b may be bends that result in one-dimensional convergence or may be bends that result in two-dimensional convergence. Thus, in the geometry of NxN reflective switching module 100 shown in Figures 4a and 4b, it may be advantageous to move curved set 118a closer to side 102a and curved set 118b closer to side 102b. Thus, reducing the distance between the sides 102a and 102b and the curved surface sets 118a and 118b will correspondingly increase the distance between the curved surface sets 118a and 118b, producing a parallelogram NxN reflection switching module 100. It FIG. 5 illustrates ray tracing of a light beam propagating through an alternative embodiment polygonal NxN reflection switching module 100. The polygonal NxN reflective switching module 100 shown in Figure 5 also creates a Z-shaped free space optical path.

FIG. 6 shows a trapezoidal reflection switching module 100 that consists of only half of the NxN reflection switching module 100 shown in FIG. 1, that is, its right half or left half. The basic difference of the reflective switching module 100 shown in FIG. 6 from that shown in FIG. 1 is that a mirror 120 is provided in the middle of the optical path between the side 102a and the side 102b. The reflectivity of the mirror 120 should be as high as possible at the wavelength of light concerned, as is well known to balance the s and n reflectivities. Equivalent side 102a
In contrast, the reflection switching module 100 of FIG. 6 is capable of selectively coupling light between the optical fibers 106, which is half the number of the NxN reflection switching module 100 of FIG. 1, but the reflection switching module 100 of FIG. Light can be coupled between these optional pairs of optical fibers 106.

FIG. 6a shows another form of NxN reflection switching module 100, a two mirror image reflection switching module of the general form shown in FIG. 6, assembled side by side. The configuration of the reflection switching module shown in FIG.
There are sides 102a and 102b on which the sets 118a and 118b of the mirror surfaces 116 are arranged so as to form a V-shape. Mirror surface 116 and sides 102a, 1 shown in FIG. 6a
The arrangement of 02b has an advantage over the arrangement shown in FIG. Compared to the arrangement shown in FIG.
The set 118a and the side 102a are divided into two: the sides 102a and 102b and the set 118a and 118b. Sides 102a and 118b and pairs 118a and 118
When b is divided into two parts, the mirror surfaces 11 corresponding to the sides 102a and 102b are formed.
The distance between the six sets 118a and 118b is reduced without increasing the deflection angle required to couple the light between two arbitrarily chosen optical fibers 106. With this arrangement, the collimator pointing tolerance can be relaxed and a reflective switching module with a large number of optical fibers can be manufactured.

In FIG. 7, the NxN reflection switching module 1 of FIG.
10 shows another trapezoidal NxN reflection switching module 100 that folds back the optical path of 00. By folding the optical path in a W shape, a reflection switching module 100 that is more compact than the NxN reflection switching module 100 of FIG. 1 can be obtained.

Considering the light beam 108 schematically shown in FIG. 3 only from the viewpoint of optical design,
The various embodiments of the reflective switching module 100 described above and illustrated in FIGS. 2, 4a, 4b, 5, 6 and 7 differ primarily in the location of the mirror surfaces 116a and 116b along the light beam 108 and in the folding of the optical path. For example, in the embodiment of the NxN reflective switching module 100 shown in Figures 4a and 4b, the mirror surfaces 116a and 116b are located at about 1/3 of the optical path length from the closest lens to the sides 102a-102b. Conversely, in other shapes / configurations of the reflective switching module 100 as shown in FIGS. 2, 5, 6 and 7, mirror surfaces 116a and 116b are provided directly adjacent sides 102a and 102b, respectively. However, as will be readily appreciated by those skilled in the art, these various configuration / shape differences, particularly the position of the mirror surfaces 116a and 116b relative to the lens 112, will affect other aspects of the optical design, which will be detailed below. .

2, 4a, 4b, 5, 6 and 6 are used to position the end 104 of the optical fiber 106 on one or both sides 102a and 102b, respectively, and the companion lens 112 and mirror surfaces 116a and 116b. Those skilled in the optical design arts will appreciate that there are an infinite number of other possible geometries and path shapes as a concept in addition to those shown in FIG. Regarding such alternative geometries for the free space optical path of the reflective switching module 100, prioritizing one arrangement relative to another possible arrangement is suitability for a particular optical switching application,
It involves problems related to size, easiness of manufacture, relief of mechanical error in assembling the reflection switching module 100, reliability, cost, and the like. That is, the trapezoidal converging beam NxN reflection switching module 100 shown in FIG. 7 in which the free space optical path is W-shaped is currently given priority for the following reasons. 1. Fits in a standard 23-inch wide communication rack. 2. Mechanical error is allowed. 3. The effective relay length for the light beam 108 is long. 4. The runs of electrical and optical cables are separated.

As mentioned above, the light beam 108 generated by the lens from the light emitted from the end 104 of the associated optical fiber 106 first strikes the associated mirror surface 116 of one of the twist scanners in sets 118a and 118b. As will be described in detail below, in the NxN reflection switching module 100 having the shape shown in FIG.
6a and 116b preferably consist of 32 twist scanners and 36 line strips. All 32 mirror surfaces 116 in each strip are preferably substantially coplanar. As an example, three adjacent mirror surfaces 116 in each strip
． It is sufficient that they are separated by an interval of 2 mm, and it is preferable that the adjacent columns of the mirror surface 116 be separated by an interval of 3.2 mm with respect to the light beams 108 incident from the adjacent sides 102a and 102b.

Also, for any type of NxN reflection switching module 100, the end 104 of the optical fiber 106, the lens 112 and the mirror surface 1 of the unbiased twist scanner.
16 is at a point 122b where the light beam 108 of the light emitted from the optical fiber 106 having the end 104 on the side 102a is preferably located behind the set 118b of mirror surfaces 116 shown in FIGS. Orientation is preferred so that it converges. This causes the light beam 108 emitted from the optical fiber 106 having the end 104 on the side 102b to converge at a point 122a located behind the set 118a of mirror surfaces 116. However, the position of the point where the light beam 108 converges depends on the specific details of the NxN reflective switching module 100. For example, in the configuration of the NxN reflective switching module 100 shown in Figure 6a, the light beam 108 is at a point 122 that is generally located after the bifurcation of sets 118a and 118b.
Are preferably converged.

By considering the mirror surfaces 116 on both sides of the sets 118a and 118b, the convergence point 122 is set in the horizontal direction. The point 122 is the two mirror surfaces 1
16 at each vertex and at the intersection of two lines each bisecting the angle at which a side extends from the respective mirror surface 116 through the mirror surface 116 to the other set 118b or 118a. Point 122 is vertically aligned with sets 118a and 1
It is located at half the height of 18b. By geometrically arranging the end 104 of the optical fiber 106, the lens 112, and the mirror surface 116 to produce the above convergence, an equal rotation angle in both clockwise and counterclockwise directions,
For the mirror surface 116 for each set 118a, 118b, the light beam 108
A minimum rotation angle is obtained that requires maximum movement to reflect from one mirror surface 116 in the set 118a or 118b to any mirror surface 116 in the other set 118b or 118a. NxN reflection switching module 100 configured as shown in FIG.
, A pair of mirror surfaces 116a and 116b are
If they are separated by 0 mm, the maximum angular rotation of the mirror surface 116 is about 3.9 ° in the clockwise direction and the counterclockwise direction.

An individual pair of optical fibers 106 and lenses 112 are inserted into the grooves to form sides 102a and 1
02b can be assembled to produce the convergence of the light beam 108 described above,
In order to obtain the maximum density of the lens 112 and the optical fiber 106, it is preferable to use an integral block in which holes are appropriately perforated. Each pre-drilled hole is a lens 112.
, And one of which is fixed around the end 104 of the optical fiber 106. Optical fiber 1 for two-dimensional focusing of light beam 108
In order to obtain the combined angle required for the axial alignment of 06 and the lens 112, the holes drilled in the block may be oriented appropriately.

In FIG. 8 a, a cylindrical microlens 11 that is a preferred embodiment made with the focal point at or as close as possible to surface 138 of lens 112.
2 is shown. As is well understood by those skilled in the fiber optic arts, the optical fiber 106 has the end 104 polished at an angle to eliminate reflective return from the end 104, thus directing the light beam 108 to the center of the optical fiber 106. Emit at an angle to the line. Since the end 104 is angled, the axis of the light beam 108 emitted from the end 104 extends from the axis of the optical fiber 106. Light beam 108
To align the axis with the axis 144 of the lens 112, the surface 138 of the lens 112 is angled to center the light beam 108 within the lens 112. Lens 1
Twelve foci are in plane 138, as described above, and end 104 of optical fiber 106 is located in the Rayleigh effect (distribution) range of light beam 108, eg, 50-60 microns from plane 138. The cylindrical surface 136 of the lens 112 has a diameter sufficient to accommodate the divergent light beam 108, which exits the lens 112 through the convex surface 142 as a quasi-parallel light beam 108.

This configuration of the lens 112 and the end 104 of the optical fiber 106 allows the light beam 1
08 is centered on the axis 144 of the lens 112 on the convex surface 142 of the lens 112 and directs the quasi-parallel light beam 108 essentially parallel to the axis 144. With respect to the lens 112, the deviation and the offset of the emission angle of the light beam 108 from the axis line 144 of the lens 112 are within an allowable range even with a normal manufacturing tolerance. For example,
The lens 112 is made of BK7 optical glass and is attached to the end 104 of the optical fiber 106.
Given an angle of °, the angle of the light beam 108 in the lens 112 is 6.78 ° and the lateral offset from the axis 144 is also at the surface 138 and also at the surfaces 138-140.
Even at mm, it is less than 50 microns. This lens 112 is LightPa
th Technologies, Inc. Marketed by
It is preferably made of m material.

Another embodiment is shown in FIG. 8 b, a “champagne cork” shaped microlens 112, which has the advantage that both the lens 112 and the optical fiber 106 can be spaced closer together on sides 102 a and 102 b. ing. The lens 112 is provided with a small diameter surface 132 that is received by the conical fiber optic collimator assembly 134 shown in FIG. The large diameter surface 136 projects from the optical fiber collimator assembly 134. In order to manufacture the champagne cork-shaped microlens 112, a part of the lens 112 shown in FIG. 8A may be removed by grinding.

As shown in FIG. 9, in addition to receiving the cylindrical lens 112 of FIG. 8a or the champagne cork-shaped microlens 112 of FIG. 8b, each fiber optic collimator assembly 134 includes an end portion of the fiber optic 106. It provides a spigot for receiving a conventional fiber optic ferrule 146 secured around 104. Converging blocks 152 arranged on both sides 102a and 102b of the reflection switching module 100, respectively.
Through a plurality of conical holes 154 having a number equal to the number N of the optical fibers 106 as shown in FIG. Focusing of the light beam 108 is accomplished by inserting and aligning the fiber optic collimator assembly 134 into the hole 154, as described above. The fiber optic collimator assembly 134 and the hole 154 are preferably formed from the same material and have mating surfaces of the same shape that taper at an angle of several degrees. The optical fiber collimator assembly 134 configured as described above and holding the optical fiber 106.
When all of them are fitted into the fitting hole 154, the optical fiber collimator assembly 134 becomes fixed to the focusing block 152, and hermetically seals the inside of the reflection switching module 100 through which the quasi-parallel light beam 108 propagates.

The converging block 152 can be machined from a single piece of metal such as stainless steel or made of ceramic. Alternatively, the converging block 152 may be composed of Kovar, 42% nickel-iron alloy, titanium (Ti), tungsten (W) or molybdenum (Mo), which is appropriately plated for corrosion resistance. All these materials
The coefficient of expansion closely matches that of lens 112, minimizing possible birefringence effects when lens 112 is heated or cooled in its operating environment.

In addition to the prioritized method described above, which provides convergence by appropriately orienting the optical fiber 106 and lens 112 on each of the sides 102a and 102b, one-dimensional (1D) or two-dimensional (2D) convergence can be achieved by other methods. May be done. For example, the configuration of the optical fiber 106 and the lens 112 may give a certain degree of convergence, and the remaining portion of the convergence may be obtained by disposing the mirror surface 116 on which the light beam 108 first strikes. For example, the mirror surface 116 of each column may be arranged along a cylindrical (cylindrical) surface. Alternatively, Figures 4a and 4
As shown in b, the optical fiber 106 and the lens 112 are arranged so that there is no convergence, that is, the light beam 108 is propagated in parallel from the sides 102a and 102b to the first mirror surface 116, and all the convergence is achieved. The mirror surface 116 may be arranged so as to give For example, the mirror surface 116a of each column is arranged along the spherical surface. In addition, a set 118a and 118b of optical fiber 106, lens 112 and mirror surface 116 is behind or behind sets 118a and 118b.
You may make it converge in b. With respect to these various alternative methods of arranging the focusing of the light beam 108, one approach is to be chosen compared to other possible methods for ease of fabrication, reduced tolerances in the assembly of the reflective switching module 100, It usually involves problems related to reliability, cost, etc.

As described above, processing the single metal piece to form the converging block 152 for converging the light beam 108 means that the individual holes 154 are under a composite compound angle with each other. The light beam 108 emitted from each fiber optic collimator assembly 134 must be directed so that it directly impinges on the mirror surface 116 immediately in front of the lens 112. If the light beam 108 even misses the mirror surface 116, it loses a substantial amount of power while passing through the reflective switching module 100. In fact, misalignment between the light beam 108 emitted from a particular lens 112 and the corresponding mirror surface 116 may cause the optical fiber 106 to become inoperative. Therefore, the alignment of each light beam 108 with the corresponding mirror surface 116 is essential for proper operation of the reflective switching module 100.

As mentioned above, the end 104 of each optical fiber 106 is positioned at a position that is the Rayleigh range of the light beam 108 emitted from the optical fiber 106 plus the store distance of the lens 112. Lens 112 typically has more centering error [centr
[ation error]. Further, due to variations in the lens 112 and the optical fiber collimator assembly 134, the axis line 144 of the lens 112 may be aligned with the optical fiber 10.
It may be slightly inclined with respect to 6. The ferrule 146 and the lens 112 may be misaligned. For all of these reasons, a structure that is an alternative to the structure shown in FIGS. 9 and 10 and that allows adjustment of the position and orientation of the lens 112 is highly desirable.

Typically, a hole 154 for receiving the lens 112 and the optical fiber 106 is drilled in the solid material to form a converging block 152 as shown in FIG. 10a. To obtain the alternative converging block 152, its surface 156, after drilling the hole 154, is slit through the hole 154 in various directions to a depth slightly greater than the length of the lens 112. After slitting, material is removed from surface 156 around each hole 154 so that each lens 112 is retained by three arc-shaped deformable posts 1577 as shown in FIG. 10b. You can As a result, the convergence block 1
A monolithically integral assembly of 52 with a plastically deformable mount for the lens 112 is obtained which projects outwardly therefrom.

The lens 112 is first fixed to the focusing block 152, preferably using an impact centering. During impact centering, post 157 flows around lens 112 and secures lens 112. Then one optical fiber 106 each
The ferrule 146 carrying the end 104 of the
Inserted in 4. The ferrule 146 is then adjusted lengthwise within the hole 154 to cause each light beam 108 to focus at the appropriate location within the reflective switching module 100, typically in the middle of both sets 118 of mirror surfaces 116. After this convergence, each ferrule 146 then preferably impacts the convergence block 152 (
Impact) fixed. This system of shock-attaching the optical fiber 106 allows
The concentricity of the ferrule 146 and the optical fiber 106 can produce a 2 micron alignment. The concentricity between the ferrule 146 and the optical fiber 106 may be maintained at several microns.

When the lens 112 and the optical fiber 106 are thus fixed to the converging block 152, the post 157 that holds each of the lenses 112 is deformed, and each lens 112 is deformed.
Accurately align with the corresponding optical fiber 106. During this alignment, the light beam 108 emitted from the lens 112 is monitored by a camera or other means while plastically deforming the pointing post 57 to direct the light beam 108. In this way, each lens 112 is tilted and displaced so that the light beam 108 emitted therefrom impinges directly on the mirror surface 116 immediately in front of the lens 112.

In most (remote) communication installations, the optical fibers are generally adapted as a duplex pair, ie one fiber carries one-way communication and the other fiber carries the other-way communication. . Suitable connectors for coupling light into two double-paired optical fibers are now available that secure two optical fibers in a pair to a ferrule. Since both optical fibers forming a double pair are switched at the same time, the reflection switching module 100 also transmits light in either direction between a pair of optical fibers 106, one on each side 102a and the other on side 102b. Because they can be coupled, a single pair of mirror surfaces 116a and 116b can be used to adapt the lens 112 appropriately for use with the dual pair of optical fibers 106, thereby providing opposite directions in each of the two optical fibers 106 of the dual pair. You can switch the light delivered to.

FIG. 11 shows a lens 112 used in the reflective switching module 100 to simultaneously switch the double pair of optical fibers 106a and 106b. Figure 1
As shown in FIG. 1, the ends 104a and 104b of the optical fibers 106a and 106b holding the dual pair of optical fibers 106a and 106b by the dual optical fiber ferrule 146 and the surfaces 138a and 138b of the lens 112 are all , Angled and polished. The angles of the surfaces 138a and 138b compensate for the off-axis positions of the optical fibers 106a and 106b, so that the surfaces of the optical fibers 106a and 106b are separated from the surface 13.
The light beams 108a and 108b striking 8a and 138b become quasi-parallel beams, exiting the convex surface 142 parallel to the axis 144 and slightly offset from the axis 144 and thus propagating through the reflective switching module 100. To do.
Both light beams 108a and 108b strike the same pair of mirror surfaces 116a and 116b, but these mirror surfaces are large enough to reflect both light beams 108a and 108b simultaneously. When these two quasi-parallel light beams 108a and 108b strike a side 102a or 102b of the reflective switching module 100 with some other identically configured lens 112 and the duplex pair of optical fibers 106, the lens 112 located there will emit light. Beams 108a and 108b are coupled to respective optical fibers 106 in a double pair.

Configuration of Twist Mirrors As mentioned above, mirror surfaces 116a and 116b of sets 118a and 118b.
Are preferably electrostatically actuated two-dimensional (2D) of the type described in the '790 patent. U.S. patent application Ser. No. 08/885883 (filed on:
(May 12, 1997) and patent document WO 98/44571 provide further more detailed information on preferential 2D torsion scanners. A hinge capable of rotating the mirror surface 116 about two non-parallel axes is equipped with a torsion sensor of the type disclosed in US Pat. No. 5,648,618 (the '618 patent), which is hereby incorporated by reference. A torsion sensor on the hinge measures the rotation of the second frame or plate coated to provide the mirror surface 116 with respect to the first frame or the second frame, respectively.

As described in the above patents, patent documents and patent applications, it is preferable to micromachine single crystal silicon using Simox, silicon-on-insulator or bonded silicon wafer substrates to fabricate torsion scanners. . Such a wafer substrate has a mirror surface 11 which is extremely flat and has a stress-free residual thickness of only a few microns.
It is also a particularly preferred starting material for torsion scanners, since it also allows the production of membranes supporting 6. As shown in FIG. 12, a silicon-on-insulator (SOI) wafer 162 is provided with an electrically insulating silicon dioxide layer 164 that isolates single crystal silicon layers 166 and 168. The torsion bar and the plate holding the mirror surface 116 of the torsion scanner are formed in the thinner device silicon layer 166, while the other parts of the torsion scanner are backside etched in the thicker handle silicon layer 168. The device silicon layer 166 has a front side 169 furthest away from the handle silicon layer 168 and a back side 170 that contacts the silicon dioxide layer 164, as is well known to those skilled in the micromachining arts. Intermediate silicon dioxide layer 164
Provides a complete etch stop for etching the wafer 162 from its backside, producing a torsion bar and plate of uniform thickness.

FIG. 13 shows a stand-alone electrostatically actuated 2D torsion scanner 172 suitable for providing the mirror surface 116 of the reflective switching module 100. The torsion scanner 172 is provided with an outer reference frame 174, to which a pair of outer torsion bending hinges 176 opposite in diameter and facing each other are connected. Torsional flexure hinge 176
Supports an inner moving frame 178 such that it rotates about an axis set by torsional flexure hinge 176. A pair of opposing inner slotted torsion bar hinges 182 on opposite diameters move the central plate 184 to the inner moving plate 1.
It is connected to 78 so that it rotates about the axis set by the torsional flexure hinge 182. The axes set by the torsion flexure hinge 176 and the torsion bar hinge 182 are non-parallel, preferably vertical.

It is important to note that the plate 184 of the torsion scanner 172 is rectangular and its long sides are molded approximately 1.4 times wider than its height. The plate 184 included in the reflection switching module 100 has a rectangular shape because the light beam 108 obliquely enters the mirror surface 116 held by the reflection switching module 100 at an angle of 45 °. Thus, for the light beam 10 reflected from the mirror surface 116, the rectangular shaped plate 184 is effectively rectangular. Plate 184 is preferably 2.5 m
mx 1.9 mm, and has a thickness of the inner moving frame 178 and the torsion bending hinge 17.
6 and torsion bar hinge 182, typically 5-15 microns. Torsional flexure hinge 176 and torsion bar hinge 182 are 200-400 microns long and 10-40 microns wide. The resonant frequency on both axes is 400-800 Hz, which allows the light beam 108 to be switched between the two optical fibers 106 within about 1-5 milliseconds. Both the front side 169 and the back side 170 of the plate 184 are made of the same metal adhesion layer, preferably 10.0 to 100.0Å titanium (Ti) or zirconium (Zr), and 500 to 800Å gold (Au) thereon. It is covered with a metal reflection layer in a perfect stress equilibrium state.

Torsional flexure hinge 176, shown in greater detail in FIG. 14a, provides various advantages over previous unfolded torsion bars. US patent application Ser. No. 09 / 388,772 and PCT application publication WO 00/13210 (filed: 1
September 2, 999, Title of invention: Microfabricated members connected by torsional flexure hinges and rotating relative to each other, inventor: Timothy G-Leta and Armando P.
(New Carmans) describe various advantages that torsion flexure hinge 176 and torsion bar hinge 182 provide. Of great importance to the reflective switching module 100 is that the torsional flexure hinge 176 is more compact than a conventional unfolded torsion bar with equivalent torsional spring constants.

The torsion bar hinge 182, shown in more detail in FIG. 14b, is similar in appearance to a conventional torsion bar hinge. However, unlike the conventional torsion bar hinge, the torsion bar hinge 18
There are several longitudinal slits 186 running through 2, which are oriented parallel to the length of the torsion bar hinge 182, for example four or five. Like the torsion flex hinge 176,
The torsion bar hinge 182 is more compact than the conventional integrated torsion bar having the same torsion spring constant. However, as disclosed in U.S. Pat. No. 5,629,790, torsion bar hinge 182 has a main torsional vibration mode and higher order modes separated from torsion flexure hinge 176. Further, the torsion bar hinge 182 has much greater stiffness in the direction perpendicular to the plate 184 than the torsion flex hinge 176. Therefore, by using the torsional flexure hinge 176 and torsion bar hinge 182 instead of the conventional unfolded torsion bar,
The twist scanner 172, which can be more closely packed, can be made smaller, which allows more optical fibers 106 to be accommodated on the sides 102a and 102b of the reflective switching module 100.

Each torsion scanner 172 included in the reflective switching module 100 is provided with a pair of torsion sensors 192a and 192b of the type described in the 618 patent. Torsional sensors 192a and 192b measure the orientation of the supported member, namely plate 184 or inner moving frame 178, relative to the supporting member, ie inner moving frame 178 or outer reference frame 174, at a theoretical resolution of about 1.0 microradian. It As described in the '618 patent, when the torsion scanner 172 is operating in the reflective switching module 100, the current is a pair of sensor current pads 1.
Flow in series through the two torsion sensors 192a and 192b between 94a and 194b. Therefore, the torsion scanner 172 has a device silicon layer 166 having a front side 1
A serpentine metal conductor 196 joined to 69 is provided. Starting from the sensor current pad 194a, the serpentine metal conductor 196 moves from the outer reference frame 174 to the inner moving frame 17
8 directly across the adjacent torsional flexure hinge 176 and lower torsion bar hinge 182.
The X-axis torsion sensor 192b positioned within is reached. X-axis torsion sensor 192b
The meandering metal conductors 196 are attached to both sides of the plate 184 and are attached to the mirror surface 116.
To the inner moving frame 178 across the plate 184 and the upper torsion bar hinge 182. The serpentine metal conductor 196 then reaches the Y-axis torsion sensor 192, which is located within the left hand torsion flexure hinge 176. From the Y-axis torsion sensor 192a, the serpentine metal conductor 196 then goes around the outer reference frame 174 to the sensor current pad 194b. Right hand torsion flexure hinge 1
A metal conductor disposed across the 76 on the opposite side of the serpentine metal conductor 196 and on the inner moving frame 178 defines a pair of inner hinge sensor pads 198a and 198b.
It is connected to the shaft torsion sensor 192b. Similarly, a pair of inner hinge sensor pads 202 has one metal conductor disposed on the outer reference frame 174 along the serpentine metal conductor 196 and the other metal conductor traveling on the opposite side of the torsion scanner 172 on the outer reference frame 174.
a and 202b are connected to the Y-axis torsion sensor 192a. A pair of grooves 204, formed only through the device silicon layer 166 opposite the inner hinge sensor pads 198a and 198b, are provided between the sensor current pad 194a and the inner hinge sensor pads 198a and 198b, and between the sensor current pad 194b and the inner hinge sensor pad. It increases the electrical isolation between 202a and 202b.

As shown in FIG. 15, both electrodes 214 used to bias the rotation of plate 184, sensor current pads 194a and 194, not shown in FIG. 15, inner hinge sensor pads 198a and 198b and Inner hinge sensor pad 202
Since the front side 169 of the plate 184 faces the insulative substrate 212 holding the electrical contacts of a and 202b, it is preferred that the back side 170 of the plate 184 provide the mirror surface 116. The plate 184 of each torsion scanner 172 is separated from the substrate 212 by a spacer not shown in FIG. 15, for example a distance of 40-150 microns. The separation between plate 184 and substrate 212 depends on how much the edge of plate 184 moves during rotation.

For the reflective switching module 100, an extremely thin plate 184 with a thickness of only a few microns is desired, and the device silicon layer 1 of the wafer 162 is desired.
Note that it can be made using the 66. Plate 184 in many cases
The torsional flexure hinges 176 and 182 may have the same thickness as the device silicon layer 166. Alternatively, as shown in FIG. 15, the torsional flex hinge 182 can be thinned by etching. For example, torsional flex hinge 182 may be 6 microns thick and plate 184 may be 10 microns thick. Similarly, in order to reduce the thickness of the plate 184 and reduce its moment of inertia, the plate 184 may be etched.
A cavity 216 may be formed in the thin plate 184 and a reinforcing rib 218 may be left in the thin plate 184.

Communication system components such as reflective switching module 100 must exhibit high reliability. The plate 184 of the torsion scanner 172 has electrodes 21
Even if it accidentally collides with 4, it must not stick to it and must immediately rotate (turn) to a specific direction. Moreover, such accidental collisions may cause torsion scanner 17
2 and the circuitry connected to the torsion scanner 172 must not be damaged. In order to eliminate sticking, the plate 184 and the inner moving frame 178 have rounded corners as shown in FIG. 13, which reduces the strength of the electrostatic field. Plate 184
The rounding of the outer perimeter of the plate reduces its effective radius of rotation resulting from the compound rotation of the plate 184 about the axes respectively set by the torsional flexure hinges 176 and 182.

In addition to rounding the perimeter of plate 184 and inner moving frame 178, FIG.
As shown in FIG. 5a, the portion where the plate 184 can contact the electrode 214 is overcoated with an electrically insulating material such as polyimide. By overcoating only the portion of electrode 214 that can contact plate 184 with electrically insulating material 219,
It is avoided that charge accumulates on most of the electrodes 214. Similarly, the torsion scanner 172
Some silicon dioxide layer 164 is left on the perimeter of plate 184 during fabrication of the device so that the metal reflective layer providing mirror surface 116 does not contact electrode 214. Alternatively, as shown in FIG. 16b, a hole 220 is formed through the metal of the electrode 214 at the accessible portion.

During operation of the reflective switching module 100, the torsion scanner 172 is at ground potential while the drive voltage is applied to the electrodes 214. The plate 184 has the electrode 21.
A large resistance (for example, 1.0 MΩ) may be connected in series with the driving circuit of the electrode 214 in order to reduce the discharge current when the electrode 4 is in contact. These resistors should ideally be located as close to the electrodes as possible. Otherwise, the conductor connecting between electrode 214 and these resistors would pick up the stray electric field, which would rotate plate 184. Therefore, one option is to overcoat a selected portion of the electrode 214, as shown in FIG. 16a, with a material that has a very high resistance but is slightly conductive,
The goal is to provide an outflow path for the DC charge from the electrode 214. In addition, all amplifiers connected to the torsion scanner 172, such as torsion sensors 192a and 192b.
The input of what receives the direction signal from the diode is to provide diode protection to prevent damage from overvoltage conditions due to electrical or accidental contact between plate 184 and electrode 214.

There are several configurations that can be advantageously used to increase the density of the limiting mirror array, typically with respect to the density of optical fiber 106 on sides 102a and 102b. For several reasons, it is preferable to arrange the torsion scanner 172 in a strip 222 as shown in Figures 16a and 16b, especially because of the large number of contacts that must occur for each torsion scanner 172. Organizing torsion scanner 172 with strips 222 increases its density beyond what can be achieved when arranged as a two-dimensional array of discrete torsion scanners 172. Each strip 222 is provided with a metal support frame to which the substrate 212 is fixed.

As described in detail below, the strip 222 is flip-chip bonded to the substrate 212 so that all electrical connections are made between the strip 222 and the substrate 212. Flat, polyimide-backed multi-conductor ribbon cable 22
6 connects to the substrate 212 so that electrical signals are exchanged between the pads 194, 198 and 202 and the electrode 214. Since each support frame 224 can be a release frame that can include reinforcing ribs, the ribbon cable 226 is free to bend and move away from the base 212.

FIG. 16 b shows a method in which the substrate 212 and the strip 222 are overlapped with a ribbon cable 226 that meanders along the stepped substrate 212 without covering the mirror surface.
This arrangement of strips 222 reduces the horizontal distance between mirror surfaces 116 of adjacent strips 222 with respect to light beam 108. Light beam 10
Since 8 is incident on the mirror surface 116 at an angle of about 45 °, the adjacent strip 222 is
The apparent distance between them is reduced by a factor of about 1.4, which results in plate 184
Is the reason why it is preferably rectangular.

One disadvantage of configuring the strips 222 as shown in FIG. 16b is that the offset between adjacent strips 222 cannot be less than the thickness of the twist scanner 172 plus the substrate 212. Further, the adjacent strip 22
When 2 and the base 212 are overlapped, it becomes difficult to remove the defective strip 222 without disturbing the adjacent strip 222.

16c and 16d, a preferred embodiment of the strip 222 and the support frame 224, with the leads 228 connecting to the torsion scanner 172, preferably the substrate 21.
It is composed of a conductive passage formed in 2. Alternatively, these lead wires 2
28 may be covered or covered from one side of the substrate 212, around one end, and to the other side. In this configuration of lead wire 228, substrate 2
Attachment of the ribbon cable 226 to 12 is not hindered. Lead wire 2
The substrate 212 can be as narrow as the strip 222 by having 28 cover or cover the substrate 212, some of which pass through the substrate 212 through the holes. When narrowed to this extent, the combination strip 222, substrate 212 and support frame 224 will set 118a and 118b.
16e, the offset between the adjacent strips 222 is now set to meet the optical requirements of the reflective switching module 100 rather than due to packaging requirements. It The optimum offset between immediately adjacent strips 222 is approximately 0-10% of the distance between plates 184 in immediately adjacent strips 222. By configuring the base 212 as shown in FIG. 16d, access to the base 212 is facilitated and the adjacent support frame 2
The strip 222 can be easily removed without disturbing the 24. Note that the lead wires 228 may extend around both ends of the substrate 212, if desired. This capability may be beneficially utilized to separate the lead 228 carrying the high voltage drive signal applied between the plate 184 and the electrode 214 from the lead 228 carrying the signals from the torsion sensors 192a and 192b.

As shown in FIGS. 16d and 16e, the ribbon cable 226 can be attached to the substrate 212 using hot bar bonding. Lead wire 228 on substrate 212
To obtain an electrical connection between the multi-conductor ribbon cable 226 and solder, solder or, preferably, an anisotropic conductive film can be used. To enhance the mechanical attachment of ribbon cable 226 to substrate 212, epoxy strain relief beads 229 are used.
Should be used.

To increase the density of optical fibers 106 on sides 102a and 102b without reducing the size of plate 184, strip 22 as shown in FIG. 17a.
The twist scanners 172 of the immediately adjacent strips 222 may be offset in the vertical direction by half the vertical separation between the twist scanners 172 in the two. Due to the aforementioned convergence criteria taken to place the light beam 108 in the reflective switching module 100, crossing the twist scanner 172 in the immediate strips 222 causes the fiber optic collimator assembly 134 to be oriented out of the quasi-rectangular array. Turned into a quasi-hexagonal close packed array. Crossing the twist scanners 172 within the immediate strip 222 does not increase the density of the twist scanners 172, but such placement of the twist scanners 172 is side 1
The density of the optical fiber 106 at 02a and 102b is increased to the extent that the diameter of the lens 112 or the optical fiber collimator assembly 134 limits the spacing between the adjacent strips 222.

The density of the torsion scanner 172 can be further increased by making the torsion scanner 172 as a fully integrated two-dimensional array rather than as a strip 222. As shown in FIG. 17b, the twist scanners 172 of the immediately adjacent rows can be interdigitated to allow the twist-flex hinges 176 of the twist scanners 172 to enter the space created between the twist scanners 172 of the immediately adjacent columns or rows of the array. it can. Incorporating the torsional flexure hinge 176 in this manner reduces the distance between the centers of the torsion scanners 172 in adjacent columns or rows, and allows the torsion scanner 172, and thus the side 102, to rotate.
The filling of the optical fiber 106 in a and 102b is close to the hexagonal closest packing.

In another embodiment of strip 222, torsional flex hinge 176 and torsion bar hinge 182 are oriented at a 45 ° angle to the vertical and horizontal axes of support frame 224. 18a and 18b show that the torsion flexure hinge 176 and torsion bar hinge 182 are oriented parallel and perpendicular to the strip 222.
Torsional flexure hinge 17 designed to more effectively utilize the area on the strip 222
6 and the torsion bar hinge 182 in an oblique configuration. The oblique orientation of the torsion flexure hinge 176 and torsion bar hinge 182 oriented at 45 ° relative to the outer reference frame 174 allows the hinges 176 and 182 to be lengthened without increasing the area occupied by the torsion scanner 172. The plate 184 is elongated in one direction for the convenience of receiving the light beam 108 incident at 45 °. Since the light beam 108 has an elliptical shape when entering the plate 184, ignoring the corners of the light beam 108 can result in the plate 184 having an octagonal shape that provides room for the outer reference frame 174. For manufacturing convenience, the side surfaces of the outer reference frame 174 are oriented in the <110> crystallographic direction of silicon. With the torsion scanner 172 thus configured, the torsion sensors 192a and 192b are oriented in the <100> crystallographic direction of silicon. Thus, the p-type device silicon layer 166, ie the wafer 162 with the p-type implant, must be used to fabricate the torsion sensors 192a and 192b. The <110> and <100> crystal directions of silicon can be made compatible by appropriately changing the processing steps.

Using the configuration of the torsion scanner 172 shown in FIG. 18b, plates 184 of size 1.5 × 2 mm are spaced apart by only 2.5 mm, effectively increasing the density of mirror surfaces 116 by a factor of 1.4. be able to. Viewed at an incident angle of about 45 ° of the light beam 108, the strip 222 is tilted at 54 °. In this configuration, the strip 222
Are oriented at 45 ° with respect to the support frame 224. This orientation of the strip 222 would be necessary if the mirror surface 116 were to completely capture the light beam 108. The support frame 224 can be oriented at 45 °, which allows all strips 222 to be of the same length and use the area on the wafer 162 more effectively.

FIG. 19 a shows another embodiment of the torsion scanner 172, which has a smaller size and thus a shorter space between the adjacent mirror surfaces 116 in the reflection switching module 100. From the above description, the torsion bending hinge 1
Obviously, positioning the 76 and torsion bar hinges 182 in the corners rather than on the sides of the plate 184 is advantageous because it reduces the size of the torsion scanner 172. In FIG. 19 a, elliptic curve 232 represents the contour of light beam 108 incident on mirror surface 116 of plate 184. Since the light beam 108 does not enter the corner of the plate 184, the inner torsion bar hinge 182 can be rotated with respect to the plate 184 using the unused corner space. Similar to the configuration of the torsion scanner 172 shown in Figure 18a, the outer torsional flexure hinge 176 continues to occupy the corners of the outer reference frame 174.

Placing the torsion bar hinge 182 at the corner of the plate 184 as shown in FIG. 19a not only reduces the size of the torsion scanner 172, but also increases the angle when the corners of the plate 184 rotate about both axes simultaneously. The synthesis of is reduced. When the plate 184 simultaneously rotates about the axes set by the torsion bending hinges 176 and the torsion bar hinges 182, the distance that the corner portion of the plate 184 moves increases due to the composition. The synthesis increases the separation required between plate 184 and substrate 212, and thus increases the voltage that must be applied between plate 184 and electrode 214 to rotate plate 184 equally. However, as is the case with the plate 184 included in the reflective switching module 100, if the aspect ratio of the plate 184 is not 1 and the plate 184 is not square, then the torsion flexure hinges 176 and 182 shown in FIG. The torsion sensors 192a and 192b in the interior are no longer in the orthogonal crystallographic direction, ie <100> or <110> of silicon.
It is not oriented in any of the directions. This can be seen from the fact that the torsion sensors 192a and 192b in torsion flex hinge 176 and torsion bar hinge 182 respond to the flex and torsion of torsion flex hinge 176 and torsion bar hinge 182, respectively.

Since the aspect ratio of the plate 184 shown in FIG. 19a is about 1.4: 1, the rotational axes 236a and 236 set by the torsion flexure hinge 176 and the torsion bar hinge 182 are set.
b intersects at about 70.5 °. However, by slightly reorienting the rotation axes 236a and 236b until they intersect at 90 ° as shown in FIG. And the torsion bar hinges 182 can be oriented in the single crystal direction of silicon, ie the <100> crystal direction. When the torsion scanner 172 is configured as shown in FIG. 19b, there is a significant amount of space in the corner of the plate 184 with respect to the inner torsion bar hinge 182, which reduces the size of the torsion scanner 172.
Further, the configuration of the torsion scanner 172 shown in FIG.
The crystallographic axis orientations of 2a and 192b are retained and the synthetic effect is significantly reduced, if not completely eliminated. However, in the configuration of the torsion scanner 172 shown in FIG. 19, the orthogonal rotation axis set by the torsion flexure hinge 176 and the torsion bar hinge 182 is oriented obliquely to the length and width of the plate 184. Nevertheless, since the plate 184 makes only a slight angular rotation during operation of the reflective switching module 100, rotation of the plate 184 does not cause a significant change in the area of the plate 184 that the light beam 108 strikes.

The twist scanner 172 shown in FIG.
To be incorporated into one of 18a or 118b and maximize their respective benefits, the set 118a or 118b needs to be reconfigured. An example of a preferred configuration of the strip 222 of the torsion scanner 172 shown in FIG. 18a is shown in FIG. 20a. As described above and as shown in Figure 20a, the strip 222 'is attached at 45 ° to the horizontal base 242 of the reflective switching module 100. In the example of FIG. 20 a, the support frame 224 ′ holding the strip 222 ′ is also 4 with respect to the base 242.
It is installed at 5 °. The two axes set by torsional flexure hinge 176 or torsion bar hinge 182 about which plate 184 rotates are represented by the x and y axes 244 in FIG. 20a. Mirror surface 11 for the same twist scanner 172
Torsional flexure hinges 17 allowed in other sets 118b and 118a of 6
6 and the maximum rotation angle of the plate 184 about the axis set by the torsion bar hinge 182 sets the sawtooth rectangular shaped field 246 of the addressable twist scanner 172 in the address set 118a or 118b.

This optimal rectangular shape field 246 is truncated at the corners and the truncated surface is a strip 222 ′.
It is skewed at about 45 °. In the example configuration of FIG. 20a, the longest strip 222 'must include at least 1.4 times more torsion scanners 172 than would be required for a rectangular array of torsion scanners 172 assembled from the strips 222 shown in FIG. 16a. However, the torsion scanner 172 can be removed from locations within the set 118a or 118b that are not addressable from the other set 118b or 118a. Thus, in the one shown in Figure 20a, only a few strips 222 'need be full length. Strip 222 'with only a few twist scanner 172
Even, it can be excluded altogether. For example, by using 40 strips 222 ′ containing up to 44 torsion scanners 172, there are as many as 1152 torsion scanners 172 with very small scan angles and relatively small mirror sizes in the set 118 a or 118 b. Can be placed. In another arrangement,
It is also possible to provide 1132 torsion scanners 172 with dimensions as small as 1.59 x 2.2 mm and requiring deflection angles of 3.69 ° and 3.3 °. Twist scanner 17
The two strips 222 ′ average 5 for the fiber optic collimator assembly 134.
It is oriented at 5 °. Although the configuration shown in FIG. 20a is slightly more complex, it significantly increases the density of the torsion scanner 172, and thus of the fiber optic collimator assembly 134, and allows more scanners to be identified for the plate 184. It can be addressable to an angle.

FIG. 20b shows the reconstruction of a torsion scanner 172 of the type shown in FIG. 19b in a set 118a or 118b. In the configuration example of this torsion scanner 172 shown in FIG. 19b, the strip 222 ″ and the support frame 224 ″ are oriented vertically, as in the example of FIG. 16a. However, the x and y axes 2 about which the plate 184 rotates
44 is oriented at 45 ° with respect to the strip 222 ″ and its support frame 224. Orienting the x-axis and the y-axis 244 with respect to the strip 222 ″ and the support frame 224 is again mirror plane. The maximum rotation angle of the corresponding torsion scanner 172 with respect to the plate 184 in the other set 118b or 118a of the 116 means setting the sawtooth octagonal or truncated rectangular shaped field 246 of the addressable torsion scanner 172 in the addressing set 118a or 118b. To do. If the rectangular shaped field 246 set for these torsion scanners 172 is pxq, then the optimum field coverage for the strip is 0.7 to 1 symmetrically arranged along the skew x and y axes 244. A square or rectangular field with an area of .2pq. The result of this is a slightly elongated rectangular shaped field 246 in the direction of the strip 222 ".
Aspect ratio, for example, 1.0: 1.3. If the set 118a or 118b has horizontally oriented strips 222 "and support frames 224", the elongated portion of the rectangular shaped field 246 will be horizontal rather than vertical. For manufacturing convenience, all strips 222 "are of the same length. Similar to the configuration of torsion scanner 172 shown in Figure 20a, there is again an area of rectangular shaped field 246 where torsion scanner 172 can be omitted.
It is advantageous to omit the short strips 222 "along the truncated surface of the rectangular shaped field 246, where the torsion scanner 172 is scarce, and allow the other strips 222" to be slightly elongated. In the example shown in FIG. 20b, the size of the plate 184 is 1.8 × 2.4 mm,
If the rotation angles of the plate 184 about the x-axis and the y-axis are 5.6 ° and 3.7 °, the number of the twist scanners 172 increases to about 1500.

In the configuration of the reflective switching module 100 described thus far, the fiber optic collimator assembly 134 is fixed to the converging block 152 positioned away from at least part of the sets 118a and 182b of the mirror surface 116. The configuration of the reflective switching module 100 requires the fiber optic collimator assembly 134 to be very well aligned with the mirror surface 116. Figure 21
In the example shown in (1), the collimating lens 112, the optical fiber 106, and the strip 222 of the torsion scanner 172 are brought close to each other to reduce the tolerance of this alignment. In this example, the strip 222 is wider than the mirror strip 262 attached to the strip 212 on the opposite side of the strip 222 to form a beam folding and deflecting assembly 264. There, the beam folding / deflecting assemblies 264 are arranged in a repetitive ordered structure such that a quasi-parallel light beam 108 reflected from a mirror strip 262 of one beam folding / deflecting assembly 264 is reflected by a mirror surface 116 of a direct adjacent twist scanner 172. Will be incident on. In the configuration shown in FIG. 21, all lenses 112 are positioned at equal and short distances from the associated mirror surface 116, so the alignment of the light beam 108 to each mirror surface 116 is less important.

Each mirror strip 262 is nominally 45 as shown schematically in FIG. 21a.
The light beam 108 is converged in one dimension (1D) by slightly tilting from the angle of °.
Can be done at. To obtain convergence in the second dimension, the fiber optic collimator assemblies 134 may be properly oriented with respect to their respective mirror surfaces 116, as shown schematically in FIG. 21b. By combining these individual one-dimensional convergences, the preferable two-dimensional convergence described above can be obtained. By selecting the orientations of the mirror strip 262 and the fiber optic collimator assembly 134, the same beam folding and deflecting assembly 26 mounted together at slightly different angles.
A suitable convergence with 4 can be obtained. In the configuration shown in FIG. 21, since the base 212 is close to the associated mirror surface 116, most of the paths having a total length of 500 to 900 mm between the sides 102a and 102b are set 118a and 118a.
It is between the pair of mirror surfaces 116 in b, reducing the angle at which the plate 184 should rotate.

All electrical connections to the torsion scanner 172 are present on the front side 169 of the device silicon alongside 166 as shown in FIG. 13, and the metal layer coated on the back side 170 of the device silicon layer 166 as shown in FIG. A light beam 108 is reflected from and exits. To make an electrical connection between the substrate 212 and the torsion scanner 172 in the strip 222, the strip 222 is preferably flip bonded to the substrate 212.
By using a substrate 212 that is larger than the strips 222, the substrate 212 can accommodate one or more strips 222. The substrate 212 can be manufactured in a variety of different ways.

Substrate 212 is preferably made of a ceramic material such as aluminum oxide (alumina), or aluminum nitride to match the coefficient of thermal expansion of silicon. To obtain a high density interconnect connecting the torsion scanner 172 to the ribbon cable 226, the ceramic material forming the substrate 212 is laser drilled or stamped to provide a conductive path.

Alternatively, the substrate 212 can be made from 100 wafers of silicon.
When the base 212 is made of a silicon wafer, a cavity 272 is formed by etching.
Can be anisotropically formed on the substrate 212 to provide a space for rotation of the plate 184, and to set a precisely adjusted spacing between the plate 184 and the electrode 214 located in the cavity 272. By forming an electrically insulating oxide on the surface of the silicon substrate 212, electrical insulation can be obtained between the lead wires 228 and between the electrodes 214. Even if the electrode 214 is integrated with the silicon substrate 212, each cavity 2
It may be attached to the silicon surface within 72.

When manufacturing the substrate 212 from a silicon wafer, it may be advantageous to integrate the electronic circuitry with it as well. As a circuit included in the silicon substrate 212, a current source that supplies currents of the torsion sensors 192a and 192b of the torsion scanner 172,
From the torsion sensors 192a and 192b to the inner moving frame 178 and the plate 18
4 includes a differential amplifier that receives a signal representing the orientation of 4 and an amplifier that supplies a high voltage signal to the electrode 214 to energize the rotation of the plate 184. By incorporating these various types of electronic circuitry into the substrate 212, the number of leads that the ribbon cable 226 must have can be significantly reduced. Inclusion of one or more multiplexer circuits in silicon substrate 212 can further reduce the number of leads in ribbon cable 226.

In response to the light wavelength of the light beam 108, the mirror surface 11 is in close proximity to the strip 222.
It may be advantageous to include on the substrate 212 a photodetector located on the surface of the substrate 212 outside the shadow cast by 6 to detect whether a portion of the light beam 108 has missed the mirror surface 116. Since the photodetector for the wavelength of light used for optical communication is transparent to these lights even if they are covered with the strip 222 other than the mirror surface 116, Part of the light beam 108 is the mirror surface 11
Detects whether 6 is missed.

22a-22c, strip 222 is adhered to substrate 212 by conductive bonds formed in various ways as described in more detail below. The conductive bond 276 rigidly couples the pad on the substrate 212 to the pad 194, 198, 202 of the torsion scanner 172 of the strip 262222. By flip-chip bonding the strip 222 and the material forming the substrate 212 that match very closely in thermal expansion coefficient, the amount of stress introduced is negligible, which keeps the strip 222 flat.

The conductive bond 276 can be made from solder, electroplated metal and / or conductive epoxy material. The conductive epoxy is attached to the conductive bond 276 and the strip 2
It provides a supple connection that absorbs the mismatch in the coefficient of thermal expansion between 22 and the base 212. The conductive epoxy can be screen-printed and dispensed from a syringe.
1. Forming protruding Au stud bumps or electroplated metal with conductive epoxy material at appropriate locations on the strip 222. 1. Improve the connection between the strip 222 and the base 212. The thermal conductivity between the strip 222 and the base 212 can be increased. Further, when the Au stud bump is obtained by coining, there is an advantage that the height can be made uniform and / or the mechanical adhesion strength with epoxy can be increased.

The conductive epoxy material typically adheres well to a substrate 212 formed using a ceramic best such as aluminum oxide or aluminum nitride. However, the conductive epoxy material does not form the same strong bond as the strip 222. The cross-sectional view of FIG. 22e shows the roughening of the contact pad surface on the strip 222 during device silicon layer 162 of wafer 162 by anisotropically etching a truncated cone-shaped trough 278. The trough 278 increases the surface bond area between the conductive bond 276 and the contact pads located on the trough 278, thereby causing the conductive bond 276 strip 222
Anchor firmly.

The mechanical bond strength between the strip 222 and the base 212 is increased, and the conductive bond 2
To reduce thermomechanical stress on 76 and to protect conductive bond 276 from environmental factors such as humidity, the gap between strip 222 and the outer circumference of substrate 212 is removed by an underfill 279 shown in FIG. 22b. You can
To prevent the underfill material from entering the cavities 276, dams must surround them at least until the underfill 279 hardens. Using a flexible material such as silicon, the base 212 and the strip 22
It is possible to absorb the mismatch in the coefficient of thermal expansion between the two.

When the substrate 212 is manufactured from silicon or polysilicon, during the manufacturing process, as shown in FIG.
A number of very small conductive vias 282 may be formed through the silicon wafer as shown in 2d. In that case, Transducers 99, p. 1500
The process as described by Calmes et al. The holes in the vias 282 are first formed in the wafer using standard Bosch strong reactive ion etching (RIE). These holes may be 50 microns wide and 500 microns deep. The wafer is then oxidized to form an electrically insulating oxide layer that separates the holes from the surrounding wafer. Next, a highly doped polysilicon layer 286 is grown on oxide layer 284 by providing a conductive path along the wafer surface and within the hole. In order to obtain the polysilicon layer 286 having sufficient conductivity, the polysilicon layer 2
It is necessary to dope vapor phase doping of 86. The conductive polysilicon layer 286 thus formed connects both sides of the wafer. If desired, the passages 282 can be isolated from each other by etching through the polysilicon layer 286 around each passage to form a ring 288. Additional metal layers, suitably patterned, can be provided on one or both sides of substrate 212 to increase the conductivity of substrate 212 and to facilitate the formation of electrical contacts to passageway 282.

FIG. 22 d shows the strip 222 attached to the substrate 212 that includes the passage 282. The electrical connection between the strip 222 and the passage 282 of the substrate 212 is again made by the conductive bond 276. An elastomer layer 292 secures the polyimide and copper sheet 294 forming the ribbon cable 226 to the side of the substrate 212 farthest from the strip 222 of the torsion scanner 172.
The ball grid or TAB bumps 298 are electrically conductive paths 28.
2 to form an electrical connection with the polyimide and copper sheet 294.
In this manner, the passage 282 having a relatively low electrical resistance is connected to the base 21 through a large number of contacts.
I am in contact through 2.

If substrate 212 is made of polysilicon or Pyrex® glass, it can be etched to form cavities 272. However, the base 212
If is made of a ceramic material or Pyrex, the electrode 214 must be deposited on the surface within the cavity 272. If the strip 222 is made from a flat sheet of material such as ceramic, a layer of material providing spacers 299 must be inserted between the strip 222 and the substrate 212 as shown in Figure 22f.
For substrates 212 without etched cavities 272, plate 18
Spacers 299 set up a precisely controlled gap between plate 4 and electrode 214 that allows plate 184 to rotate. Spacer 299 can also be arranged to provide a dam that prevents underfill 279 from entering cavity 272. The spacers 299 can be made by screen printing a material on the substrate 212 and then lapping the material to a suitable thickness. Preferably, E.
I. du Pont de Using any of the dry coatings patterned by photolithography, spacers 29
9 is made. By stacking several layers of dry coating films of the same or different thickness, the spacer 2
99 can be given a desired thickness. When the dry coating is used as a negative, a series of films can be laminated and exposed after each lamination without development, resulting in a cone-shaped structure. Once the spacer 299 is secured to the substrate 212, a syringe is used to dispense a conductive epoxy material for the conductive bond, which requires curing or b-staging before the substrate 212 faces the strip 222. do not do. The spacer 299 thus set between the base 212 and the strip 222 mechanically separates the adjacent torsion scanners 172.

It has been found that the steep side surfaces 302 formed by the 111 surface exposed by anisotropic etching of the handle silicon layer 168 of the wafer 162 shown in FIG. 15 are extremely advantageous for flip chip bond formation. The side surface 302 is the back side 17 of the plate 184.
The mirror surface 116 on the zero is well protected from damage during manufacture and the strip 22
In addition to mechanically reinforcing 2, the steep angles are unlikely to interfere with the light beam 108 that is incident on the mirror surface 116 at an angle of about 45 °. Furthermore, an integrated circuit (I
C) protects the mirror surface 116 from contamination by scratching the ultra-thin layer 30 on the back side of the handle silicon layer 168, similar to that used in masks.

Since the handle silicon layer 168 is present surrounding the mirror surface 116, mounting the torsion scanner 172 in a flip-chip configuration is also advantageous because it can reduce light scattering as shown in FIG. When the light beam 108 switches between the mirror surfaces 116, an antireflection layer 312 that effectively absorbs incident stray light may be coated on the backside of the steeply inclined side surface 302 and the handle silicon layer 168. Steep side 3
02 also scatters stray light from the light beam 108 at an extremely large angle,
When the light beam 108 switches between 16, it blocks the side 102a or 102b through which the light beam 108 propagates from receiving stray light.

FIG. 24 is a reflection switching module 100, as previously described, shown in FIGS. 2, 4a, 4b, 5, 6 and 7, where the environment completely surrounds the optical path traveled by the light beam 108. The one housed in the housing 352 is shown. as mentioned above,
Reflective switching module 100 mechanically connects sides 102a and side 102b and sets 118a and set 118b to maintain their precise alignment. An environmental housing 352 that encloses the environment and protects the reflective switching module 100 may provide temperature regulation to maintain a stable operating environment for the reflective switching module 100. Environmental housing 35
Flowing a regulated dry gas such as nitrogen through the reflection switching module 1
Moisture may be prevented from condensing in 00. The environmental housing 352 may also be slightly pressurized to prevent ambient air from entering the reflective switching module 100. The environmental housing 352 may also include an unsaturated micro dryer 353 as described in US Pat. No. 4,528,078 to control the humidity of the atmosphere within the reflective switching module 100. A feedthrough 356 of the ribbon cable 226 extends through the wall of the environmental housing 352. The fiber optic collimator assembly 134, which is secured near the end 104 of the fiber optic 106, is plugged directly into the converging block 152 which projects through the environmental housing 352. Within the environmental housing 352, the path of the ribbon cable 226 is carefully planned to reduce the potential for optical misalignment, avoiding stress on the reflective switching module 100, particularly the support frame 224 and substrate 212. .

Optical Fiber Switch FIG. 25 shows a modular optical fiber switch according to the present invention with a general reference number 400. The fiber optic switch 400 is equipped with a standard 23 inch wide (remote) communication rack 402), at the base of which an environmental housing 352 is positioned to house the reflective switching module 100. The environmental housing 352 that houses the full-twist scanner 172 is mounted on a special pedestal on the floor directly below the rack and is connected to the rack 402 with extremely high flexibility. By supporting the environmental housing 352 on a special pedestal, vibration is minimized and the environmental housing 352 is thermally coupled to the floor to improve its thermal regulation.

Mounted on the rack 402 above the port card environmental housing 352 are a number of duplex sockets 404 contained on a port card 406 suitable for receiving a duplex pair of optical fibers 106. One optical fiber 106 of the duplex pair carries one light beam 108 to the fiber optic switch 400, and the other receives one light beam 108 from the fiber optic switch 400. The port card 406 is arranged in the rack 402 in either a horizontal direction or a vertical direction, and directly adjacent to the port card 4
It can be individually taken out or attached without interfering with 06. As is customary in the communications industry, the port card 406 is hot swappable. Since the reflective switching module 100 may have a space between the spare mirror surfaces 116, even if some of the mirror surfaces 116 are broken, the optical fiber switch 400 can retain its operation capability. As a general rule, all or less of the optical fibers 106 connected to one port card 406 can be
It is immediately apparent that the light beam 108 from 06 can be received. Similarly, all or any number of optical fibers 106 connected to one port card 406 can carry a light beam 108 to that port card 406. Optical fiber 106 can be, but need not be, organized in double pairs as shown in FIG.

In the block diagram of FIG. 26, everything to the left of dashed line 412 is included in port card 406, and everything to the right of dashed line 414 is included in reflective switching module 100. The area between the dashed lines 412 and 414 is rack 4
02 backplane is shown. Each port card 406 is equipped with the electronics, alignment optics and electrical optics required to control the operation of a portion of the reflective switching module 100. Thus, all the optical fibers 106 included in the reflective switching module 100 connect to the port card 406. Similarly, all of the torsion scanners 172 whose light beam 108 is incident on the mirror surface 116 are connected to the port card 406 via the substrate 212 and the ribbon cable 226. Sixteen or thirty-two optical fibers 1 each port card 406, half of which are supposed to receive the light beam 108 from this port card 406 and half of which carry the light beam 108 to this port card 406.
06 is preferred, but not necessary. In FIG. 26, the odd numbered optical fibers 106 ₁ , 106 ₃ , ..., 106 _2n−1 carry the light beam 108 to the reflection switching module 100, while the even numbered optical fibers 106 1. ₂ , 106 ₄ , ..., 106 _2n carry the light beam 108 from the reflective switching module 100.

A light source 42 used to supply light to the port card 406 and connect it to the optical fiber 106 to servo align the reflective switching module 100.
2 and a directional coupler 424. The directional coupler 424 may alternatively receive light received from the reflective switching module 100 via the optical fiber 106 and the photodetector 4
26. Further, the port card 406 is accompanied by driving / sensing / control electronics 432, for example, a digital signal processor (DSP), and transmits an electric signal to the electrode 214 in the base 212 and the base 212 via the ribbon cable 226. A circuit for exchanging with the torsion sensors 192a and 192b included in each attached torsion scanner 172 is provided. Drive / sensing / control electronics 4
32 controls the orientation of mirror surface 116, including the implementation of servo loops to ensure proper orientation, and also communicates with supervisory processor 436 via RS232 data communication link 438.

The backplane between dashed lines 412 and 414 includes a connection of optical fibers 106 to the port card 406, preferably a single mode optical fiber ribbon cable connecting, for example, 12, 16 or more optical fibers 106. For use with multiple fiber connections. The pack plane between dashed lines 412 and 414 is also provided with all of the ribbon cables 226, data communication links 438, and other connections such as the power lines required to operate the drive, sense, and control electronics 432.

A light beam 108 is coupled between an optical fiber 106 on side 102a and an optical fiber 106 on side 102b to orient a pair of mirror surfaces 116, one in set 118a and the other in 118b. Therefore, each mirror surface 116 forming the above pair
These mirror surfaces 116 are appropriately initially oriented using predetermined angular coordinates that specify the biaxial center rotation of the. Thus, in the NxN reflection switching module 100,
Ignoring the auxiliary mirror surface 116 included in the reflective switching module 100, the fiber optic switch 400 must store a value of 4 × N ² for the orientation signal generated by the torsion sensors 192a and 192b provided in each torsion scanner 172. Accordingly, the reflective switching module 100 is provided with the look-up table 452 of FIG. 27a maintained by the monitoring processor 436, which is used for orientation signals at any time during the operational life of the fiber optic switch 400. The value of 4 × N ² is stored.

The initial determination of the value of 4 × N ² for the orientation signals generated by the torsion sensors 192a and 192b included in each torsion scanner 172 may be performed analytically. During assembly of the optical fiber switch 400, the analytically determined coordinate and orientation signals are fine tuned to accommodate manufacturing tolerances and the like. Furthermore, throughout the operational life of the optical fiber switch 400, these coordinates and orientation signals may be updated if desired. Therefore,
The look-up 452 stores sensor offsets and temperature compensation because the compensation data for the initial values of the coordinate and orientation signals, such as the temperature coefficients of the torsion sensors 192a and 192b, are well characterized.

In one preferred embodiment of the optical fiber switch 400, the orientation signals generated by the torsion sensors 192a and 192b are used by the servo system having a higher frequency in controlling the orientation of each mirror surface 116. The frequency response of this high frequency servo system allows each pair of mirror surfaces 116 to be accurately oriented when switching one pair of optical fibers 106 to another. Further, according to the wide frequency servo system, the orientations of all the mirror surfaces 116 are maintained even if there is mechanical shock or vibration. To ensure the correct orientation of each pair of mirror surfaces 116 during operation of the fiber optic switch 400, the fiber optic switch 400 also employs the low frequency optical feedback servo described in detail below.

When initially aligning a pair of mirror surfaces 116, one on set 118a and the other on 118b, one is placed between one optical fiber 106 on side 102a and another optical fiber 106 on side 102b. To couple the light beam 108, the stored value of the orientation signal is sent from the lookup 452 to two two-axis servos 454 provided on the port card 406 for each torsion scanner 172 that exchanges the signal with the port card 406, respectively. . Each 2-axis servo 454 sends a drive signal to the ribbon cable 22.
The signal is transmitted to the electrode 214 provided on the substrate 212 via 6 to rotate the mirror surface 116 to a predetermined direction. Two torsion sensors 192a provided in each torsion scanner 172.
And 192b send their respective orientation signals back to their respective two-axis servos 454 via ribbon cables 226. Each two-axis servo 454 compares the orientation signal received from the respective associated torsion sensor 192a and 192b with the value of the orientation signal received from the lookup 452. If there is a difference between the stored direction signal value received from the lookup 452 and the direction signal received by the two-axis servo 454 from the respective torsion sensors 192a and 192b, the two-axis servo 454 will cause the electrode 2 to move.
The transmit drive signal is modified accordingly to 14 to reduce such differences.

FIG. 27 b shows one of the two identical channels, the X-axis or the Y-axis of the biaxial servo 454. As shown in the figure and as described above, the current source 462 provided on the port card 406 supplies current to the series-connected torsion sensors 192a and 192b of the torsion scanner 172. One or the other of the torsion sensors 192a and 192b, FIG.
In this example, the differential output signal from the X-axis torsion sensor 192b is supplied in parallel to the measurement amplifier 463 provided in the port card 406 via the ribbon cable 226.
The output signal proportional to the signal generated by the X-axis torsion sensor 192b is supplied to the measurement amplifier 46.
3 transmits to the error amplifier 464.

As described above, the drive / sensing / control electronics included in the port card 406 includes a DSP 465 that executes a computer program stored in random access memory (RAM) 466. RAM 466 is also supplied by look-up 452 maintained by surveillance processor 436 to mirror surface 116.
A direction signal value that specifies the direction of is also stored. The computer program executed by the DSP 465 retrieves angular coordinates on either the X-axis or the Y-axis as appropriate and sends them to a digital-to-analog converter (DAC) 467. DAC465 is DS
Convert the digital data format angular coordinates received from P465 into an analog signal,
This is transmitted to the input of the error amplifier 464.

The output of the error amplifier 464 is the analog signal representing the angular coordinates and the X-axis torsion sensor 19
A signal proportional to the difference from the signal from the measurement amplifier 463 proportional to the signal generated by 2b is transmitted to the integrating circuit 472. Amplifier 473, resistor 474, and capacitor 47
An integrator circuit 472, consisting of 5 networks, sends the output signal directly to the input of summing amplifier 476a and to inverting amplifier 477. Inverting amplifier 477 feeds the output to the input of second summing amplifier 476b. In addition to the signals received directly from integrating circuit 472 and indirectly from integrating circuit 472 via inverting amplifier 477, summing amplifiers 476a and 476b also receive a fixed bias voltage. Summing amplifiers 476a and 476b send output signals proportional to the sum of their respective input signals to the inputs of a pair of high voltage amplifiers 478, respectively. Each high voltage amplifier 478 sends a drive signal via ribbon cable 226 to either the X-axis electrode or the Y-axis electrode of torsion scanner 172.

In this manner, the two-axis servo 454 supplies the electrode 214 of the torsion scanner 172 with driving signals that are symmetrically larger and smaller than the voltage set by the bias voltage supplied to the summing amplifiers 476a and 476b. . 2-axis servo 45
The drive signal supplied to the electrode 214 by the electrode 4 is appropriately modified so that the torsion sensors 192a and 1
The difference between the output signal from 92b and the orientation signal value specified in lookup 452 is reduced.

Since single crystal silicon at room temperature does not undergo plastic deformation, is free of dislocations, has no loss and does not exhibit fatigue, the torsional flexure hinge 176 and torsion bar hinge 1 made of this material.
82 has stable mechanical properties for many years. Therefore, the torsion flexure hinge 176
And the long-term stability of the torsion bar hinge 182 in combination with the torsion sensors 192a and 192b ensures a nearly accurate alignment of each pair of mirror surfaces 116 by the orientation signal value that the lookup 452 supplies to the two-axis servo 454 pair. You can do it.

However, the inclusion of an optical servo loop in an optical fiber switch, as disclosed in the 463 and 153 patents, ensures accurate alignment, rather than near. In order to implement such an optical servo loop, as shown in FIG. 26, one directional coupler 424 and one optical detection are provided for each optical fiber 106 in each port card 406 included in the optical fiber switch 400. It is provided with the vessel 426. Each directional coupler 424 couples about 5 to 10% of the light propagating through one optical fiber provided in this directional coupler 424 to another optical fiber, and
5-90% remains in the original optical fiber. Therefore, when the light source 422 is turned on, 5-10% of the light emitted from the light source 422 to the directional coupler 424 enters the incoming optical fiber 106, eg, the optical fiber 106 ₁ and travels along the optical fiber 106 to the reflective switching module 100. 95-90 of any other light already propagating towards
% To the reflection switching module 100. The reflective switching module 100 couples this composite light from an incoming optical fiber 106, eg optical fiber 106 _1, to an outgoing optical fiber 106, eg optical fiber 106 ₂ . Idemitsu fiber 106, for example, upon reaching the directional coupler 424 associated to the optical fiber 106 _2, 5 to 19% of the light received from the reflective switching module 100 through the directional coupler 424 from the optical fiber 106, the directional coupler To a photodetector 426 connected to 424. If desired, the optical fiber switch 400 introduces light into the optical fiber 106 and transmits it through the reflective switching module 100,
The ability to collect a portion of the transmitted light is then utilized to analyze and adjust the initial operating conditions of the particular pair of mirror surfaces 116.

When considering the operation of this optical servo section of the optical fiber switch 400, the optical servo aligns a pair of mirror surfaces 116, which is the direction in which the alignment light propagates through the pair of mirror surfaces 116. It is important to pay attention not to be concerned with the incoming optical fiber 106 to the outgoing optical fiber 106 or vice versa. Therefore, as a general rule, the port card 406 is the fiber optic switch 40.
It is necessary to provide the light source 422 only to half of the optical fibers 106 provided in 0, for example, the all-in optical fiber 106 or all-out optical fiber 106. However, in order to facilitate the flexible and reliable operation of the optical fiber switch 400 in a communication system, the omnidirectional coupler 424, ie, both sources connected to the incoming optical fiber 106 and the outgoing optical fiber 106, has a light source 422. Can be provided.

When first aligning the pair of mirror surfaces 116, the optical fiber switch 400 detects that sufficient light has propagated along the incoming optical fiber 106 and the optical fiber switch 400 then aligns. This incident light is used for. However, if the light propagating along the incoming optical fiber 106 is insufficient, the light coupled from the light source 422 to the optical fiber 106 may be intensity modulated at an extremely low frequency, eg, switched on and off, and photodetected. The signal generated by the instrument 426 is analyzed and the optical fiber 1
The presence or absence of modulation at 06 is detected. When the light from the light source 422 is used for alignment, the port card 406 through which the output fiber 106 passes prevents the intensity modulated light from exiting the fiber optic switch 400. If the output of the port card 406 is equipped with a 1 × 2 switch and the modulated light generated by the light source 422 is directed to the vacant-end optical fiber, the light on the optical output fiber 106 is switched to the optical fiber switch 400.
You can keep it inside. By modulating the light generated by the different light sources 422 differently, eg, at different frequencies or in different patterns, the reflective switching module 100 may include a mirror surface 116 that couples the light beam 108 between the pair of ends 104. Many different pairs of initial alignment can be done at the same time,
You will also be able to verify that a particular connection is correct.

Now referring to FIG. 26 a, any directional coupler 424 of the port card 406.
Output provides light to a telecom signal strength photodetector 482. Any telecom signal strength photodetector 482 receives and responds to a portion of the light that propagates along the optical fiber 106 and enters the reflective switching module 100, whether the incoming or outgoing optical fiber 106. Thus, after the initial alignment of the pair of mirror surfaces 116 is completed, such as by using the intensity-modulated light from the light source 422, the output signals from the two telecom signal intensity photodetectors 482 accurately reflect the mirror surfaces 116. Tells whether the port card 406 should provide light from the light source 422 for alignment, or if the incoming optical fiber 106 is carrying a telecom signal signal of sufficient strength to obtain accurate optical alignment. If the signal from the telecom signal strength photodetector 482 indicates that neither of the two optical fibers 106 is carrying sufficient light for accurate optical alignment, the port card 406 will cause the light source 422 to
Is turned on to obtain the required light, otherwise the light present on the incoming optical fiber 106 is used for this purpose.

One technique for using the light introduced into the optical fiber 106 from the light source 422 shown in FIG. 26a assumes that the light source 422 uses 850 nm light from a relatively inexpensive laser diode. In this approach, the alignment wavelength photodetector 484 sensitive to red wavelength light may be an inexpensive silicon photodetector. But light source 4
In addition to the 850 nm light generated by 22, the input optical fiber 106 may carry light having an optical communication wavelength whose output (power) is larger than that generated by the light source 422, for example, 1310Å or 1550Å. The light source 422 _2j-1 is generated and supplied to the reflection switching module 100 via the optical fiber 106 _2j-1 8
The output of the directional coupler 424, which emits some of the light received by the port card 406 from the reflective switching module 100, directs such light to the dichroic mirror 486 _2j to ensure separation of the 50 nm aligned light from the optical communication wavelength. The dichroic mirror 486 _{2j aligns} the 850 nm alignment light with the alignment photodetector 48.
The light of the optical communication wavelength is transmitted while being reflected by 74, and is directed to the telecom signal monitoring photodetector 488. If the reflective switching module 100 is completely bidirectional, and any optical fiber 106 can be the _{incoming or outgoing} optical fiber 106 at any given moment, then the dichroic mirror 486 _2j-1 can be _coupled to the directional coupler 424 _{2j-. 1 is} used together with the light from the light source 422 _2j-1 to detect the telecom signal monitoring photodetector 488 _2
It should be separated from the light of the optical communication wavelength that _j-1 receives.

For several reasons, the precise optical alignment of the mating mirror surfaces 116 is first completed to enter the optical fiber 10 through the reflective switching module 100.
It is advantageous to turn off the light source 422 and use light coming into the fiber optic switch 400 at the optical communication wavelength to periodically check the alignment after making the connection between the optical fiber 6 and the output fiber 106. Is. The light source 422 and the photodetector 426 are shown in FIG.
It remains as shown in 6a. When operated in this way, the telecom signal strength photodetector 482
First receives light of an optical communication wavelength that enters the optical fiber switch 400 via the duplex socket 404, and detects a loss of light or a modulation reduction of incoming light. During such operation of the fiber optic switch 400, the telecom signal monitoring photodetector 488 and the telecom signal intensity photodetector 482 cooperate to periodically monitor and maintain the characteristics of the light sent through the reflective switching module 100. . Torsional sensors 192a and 192b
Tests have demonstrated that the orientation signal supplied to the two-axis servo 454 from the device maintains the mirror surface 116 in proper alignment for extended periods of time, eg, hours. Thus, after accurate optical alignment of the paired mirror surfaces 116 is reached, the drift, temperature change, and support frame 224 of the torsion sensors 192a and 192b may occur.
, And possibly also the substrate 212, to compensate for mechanical creep and the like of the reflective switching module 100, requiring a fairly infrequent adjustment.

Another approach to detecting the alignment light provided by the 850 nm light source 422 is to use a dichroic mirror 486 _2j and its associated photodetectors 484 and 484 as the composite sandwich photodetector shown in FIG. 26b. Can be replaced with In the composite sandwich photodetector shown in the same figure, a silicon photodetector 492 is mounted on a long wavelength photodetector 494 such as a germanium (Ge) or indium gallium arsenide (InGaAs) photodetector. The composite sandwich photodetector absorbs short alignment wavelengths at the silicon photodetector 492. However,
The long wavelength of the optical communication light passes through the silicon photodetector 492 without being substantially attenuated, and is absorbed by the long wavelength photodetector 494. With a composite sandwich photodetector, these two signals are completely separated. The InGaAs photodetector can be replaced with a second Ge photodetector to detect long wavelength light, but the sensitivity is lower than that of the InGaAs photodetector. However, with the use of 850 nm light for alignment, the directional coupler 424 becomes a multimode device that is coupled to the optical fiber 106, and the portion of the light that leaves the optical fiber 106 changes over time. Then there is the difficulty.

850n to use exact optical alignment of paired mirror surfaces 116
In order to avoid the difficulties associated with using m-light, it is possible and appropriate to be able to provide light of the optical communication wavelength from the light source 422, eg 1310Å or 1550Å. Light of these wavelengths can be obtained by an inexpensive vccell. Although vcsell lacks the precise wavelength or stability of such an expensive laser source of light, the precision and stability provided by the laser source is not required to obtain the optical alignment of the paired mirror surfaces 116. The use of light of the optical communication wavelength has the advantage that the alignment photodetector 484 can be omitted and that the coupling coefficient of the directional coupler 424 is higher than that of 850 nm light and is stable. Therefore, vcsell requires less than 850 nm light and power to obtain optical alignment.

Since any fiber optic 106 goes through the port card 406, a significant portion of the cost of manufacturing the fiber optic switch 400 is at the cost of the port card 406. Therefore, it is economically advantageous to reduce the cost of the port card 406 as much as possible. Thus, if the initial optical alignment of each pair of mirror surfaces 116 requires the use of an expensive laser to generate light at the optical communication wavelength for the light source 422,
The source cost may be shared among the directional couplers 424 using a 1xN optical switch. Since such a 1 × N optical switch supplies light to all port cards 406,
It will be extremely large. Alternatively, in order to improve reliability, the optical fiber switch 4
It is also possible to have several such optical communication lasers with 1xN optical switches where 00 is smaller, each of which supplies light only to the directional coupler 424 provided in one port card 406.

In the description so far, the directional coupler 424 is used in the port card 406 to cause light to enter the optical fiber 106 and to extract light from the optical fiber 106. Since the directional coupler 424 is a fairly expensive component, it would be advantageous to reduce their cost. FIGS. 26c and 26d show the use of a low cost bent fiber tap 495 typically used to weld optical fibers to direct light into and out of the optical fiber 106. .

[0116]   In the example of Figure 26c, each incoming optical fiber is wrapped around a sufficiently small grooved mandrel.
106_2j-1Bends and light is emitted from the optical fiber 106 as is known in the art.
Try to fire. According to this technique, an optical filter for the light emitted from the light source 422 is used.
Iba 106_2j-1Even if it enters the core or exterior (clad) of the
This is possible, although less desirable because it allows light propagation. In that case
Optical fiber 106_2j-1Light propagating in the core of the
Therefore, the light output fiber 106_2jResulting in a light beam 108 directed at. Each Idemitsu fa
Iba 106_2jAlso bends around the mandrel 496,_2j
The light emitted from the photodetector 426_2jTo hit. Photodetector 426_2j
Has two compartments, one compartment 426a for alignment light monitoring, the other compartment
Section 426b can be used for optical monitoring at the optical communication wavelength. Alternatively, optical inspection
The dispenser 4262j is shown in FIG. 26b, and the section 426a and the section 426b described above are
They may overlap each other.

As described above, the telecom signal intensity photodetector 482 _2j-1 enters the optical fiber 1
The section 426b _2j monitors the light passing through the reflective switching module 100 at the optical communication wavelength, while monitoring the loss and modulation loss of the optical communication light propagating in the reflective switching module 100 along 06 _2j-1 . Telecom signal strength photodetector 4
82 _2j and photodetector 426 _2j-1 are two _- way duplex optical fiber 10
6 performs the corresponding function.

If the wavelength of the alignment light is the same as that of the optical communication light, it is not necessary to use tandem detection. As mentioned above, in principle, the same light source 422 can inject light into several optical fibers 106 at the same time. The alignment light can be connected to both the core and the clad of the optical fiber 1062j-1. When coupled to the cladding, the absorber 4 along the _output fiber 106 _2j passing through the mandrel 496.
By providing 97, the alignment light can be removed from the light output fiber 106 _2j . This allows virtually any wavelength of light to be used in sequence to align the mirror surface 116 because the alignment light does not propagate beyond the port card 406. Bent fiber taps are all optical fibers 1 that enter or exit port card 406.
06 can be used.

There are other possibilities to reduce the cost of the port card 406. For example, the movement of the plate 184, which carries the mirror surface 116, is slower than that of the digital electronic signal, and the electrode 214 and the plate 184 form a capacitor, which accumulates the applied voltage in a short time. The circuit can be time-shared between several different pairs of electrodes 214. FIG. 27c shows a circuit for sharing a single channel of one two-axis servo 454 by several different electrode 214 pairs. In the example of FIG. 27c,
The output signals from the high voltage amplifiers 478a and 478b are high voltage multiplexers 512.
a and 512b, respectively. The signal sent from the DSP 465 via the set of digital control lines 514 is transferred to the high voltage multiplexer 512a.
And other inputs of 512b. High voltage multiplexers 512a and 51
2b is connected to each electrode 214 connected to one port card 406, for example, all electrodes 214, respectively.

The digital select signal supplied to the high voltage multiplexers 512a and 512b is such that the voltage at the output of the high voltage amplifiers 478a and 478b is controlled by the high voltage multiplexers 512a and 512b to determine which electrode pair out of several electrode pairs 214. To be applied to each. When a particular electrode 214 pair is to be selected, the appropriate digital select signal is sent to the high voltage multiplexers 512a and 512b, and the DSP 465 also sends data to the DAC 467 specifying the appropriate output voltage. The high voltage amplifier 4 then responds to the data received by the DAC 467.
78a and 478b generate the appropriate drive voltage for the selected electrode 214 pair, and high voltage multiplexers 512a and 512b couple that voltage to the selected electrode.

The capacitance created by the pair of electrodes 214 and their associated plates 184 spans the time interval between successive connections between electrodes 214 and high voltage amplifiers 478a and 478b via high voltage multiplexers 512a and 512b. A small capacitor 516 may be connected between the output signal lines of the high voltage multiplexers 512a and 512b and circuit ground if the magnitude is not sufficient to properly store the applied voltage. If switching is fast enough, a single pair of high voltage amplifiers 478a and 478b is sufficient for all electrodes 214 connected to port card 406. A digital computer program executed by DSP 465 selects the order of electrode 214 pairs to minimize the voltage changes that high voltage amplifiers 478a and 478b must supply to successive electrode 214 pairs, thereby causing high voltage amplifier 478a.
And 478b required slewing may be reduced.

Alternatively, since the electrostatic force between the plate 184 and the pair of electrodes is independent of whether the applied power is positive or negative, the plate 184 is rotated by alternating current (AC) instead of direct current (DC). Can also be used. Further, a step-up transformer can be used to apply the AC drive voltage between the plate 184 and the pair of electrodes 214. By using a step-up transformer, the primary side of this transformer will receive a lower voltage that is more compatible with the semiconductor device, simplifying the circuit for applying the drive signal to the electrodes and eliminating the need for a high voltage device.

FIG. 27d shows a circuit that applies an AC voltage to the electrodes 214 of the torsion scanner 172 to rotate both the plate 184 and the inner moving frame 178. The circuit shown in FIG. 27d includes three high frequency transformers 5, each preferably having a ferrite core.
22, 524, 526 are provided. The primary winding 532 of the transformer 522 is provided by an oscillator 528 with an AC low voltage, for example at a pp value of 10V, at a high frequency, significantly higher than the mechanical resonance frequency of the plate 184. The transformer 522 increases the AC voltage received from the oscillator 528 by a factor of 20, increasing the pp value at the secondary winding 534 of the transformer 522 to about 200V. The secondary winding 534 of transformer 522 is connected to the center taps of transformers 524 and 526 and secondary windings 536a and 536b, respectively. The terminals of both ends of the secondary winding 356 a of the transformer 524 are connected to the plate 184.
Is connected to electrodes 214a and 214b facing each other. Similarly, both terminals of the secondary winding 536 b of the transformer 526 are connected to the electrodes 21 facing the inner moving frame 178.
4a and 214b.

The AC low voltage supplied to the primary winding 532 of the transformer 522 may also be multiplied by the DAC.
Applied to the inputs of 542a and 542b directly and through inverting amplifier 538. Similar to the DACs 542a and 542b shown in FIG. 27b, the other inputs of the multiplying DACs 542a and 542b receive the angular coordinate data for the plate 184 and the inner frame directly from the DSP 465. The outputs of the multiplier / divider DACs 542a and 542b are connected to the primary windings 544a and 544b of the transformers 524 and 526, respectively. The multiplying / dividing DACs 542a and 542b thus connected to the transformers 524 and 526 are adjustable to the primary windings 544a and 544b of the in-phase or out-of-phase transformers 524 and 526 applied to the primary winding 532 of the transformer 522. AC voltage can be applied. Transformers 524 and 526 are both multiplier / divider DAC 542.
40 times the AC voltage received from a and 544b respectively, and the secondary winding 356a
And 536b, the pp value increases to 400V. If the multiply-and-divide DACs 542a and 544b do not apply voltage to the primary windings 544a and 544b of the transformers 524 and 526, no torque is applied to either the plate 184 or the inner moving frame 178.

In FIG. 27e, the multiplication / division DAC 542 is responsive to the data received from the DSP 465.
When a applies an AC voltage to transformer 524 in phase with the voltage applied to primary winding 532 of transformer 522, secondary winding 534 of transformer 522 and plate 18
4 shows waveforms at electrodes 214a and 214b facing each other. Since the electrostatic force between the plate 184 and one electrode is independent of the sign of the applied voltage,
For the waveform shown in FIG. 27e, the forces exerted on plate 184 by electrodes 214a and 214b are different. The multiplication / division DACs 542a and 544b are DS
Primary winding 5 of transformers 524 and 526 in response to data received from P465.
Not only is it possible to provide unequal in-phase AC voltages on 44a and 544b, but this data also allows the multiplication and division DACs 542a and 544b to move the primary winding 54 as shown in FIG.
It is also possible to apply a voltage that is out of phase across 4a and 544b.

The net result of applying a voltage to electrode 214a as shown in FIGS. 27e and 27f is that plate 184 approaches one of electrodes 214a or 214b and tilts away from the other electrode 214b or 214a. The inertia of the plate 184 smoothes the effect of the intermittent force applied at twice the frequency of the AC voltage generated by the oscillator 528. If the frequency of the AC voltage generated by oscillator 528 is low enough, the resulting microvibration of plate 184 can be used for phase sensitive detection of the signal for accurate alignment of light beam 108. Instead of changing the AC voltage applied to the transformer 524, the constant amplitude A applied to the transformer 524 is changed.
Unequal forces can also be applied to the plate 184 from the electrodes 214a and 214b by changing the phase relationship between the C voltage and that applied to the transformer 522. Multiplication DAC 544b and transformer 5 for rotating the inner moving frame 178.
The operation of 26 is identical to that described above for plate 184.

The biaxial servo 454 symmetrical DC voltage shown in FIG. 27b is applied to the pair of electrodes 214, and the plate 184 is arranged so that the voltage of one electrode 214 and the voltage of the other electrode 214 are increased and decreased by equal amounts. Is to rotate. With such a drive voltage, capacitive coupling to the signals from the torsion sensors 192a and 192b will normally occur on the electrode 214.
Since they are symmetrically exposed to the voltage applied to the pair, they are balanced. Furthermore, to minimize switching and transient noise, the long output lines from the torsion sensors 192a and 192b are arranged to be equally exposed to positive and negative voltage swings. A technique for balancing the exposure of these signal lines to the drive signal supplied to the electrodes 214 involves the inclusion of additional lines in the connector and exposing the voltage to the angular sensor lines symmetrically to both voltage swings. It may be applied as described above. Alternatively, shield lines can be used for the signals from the torsion sensors 192a and 192b and the drive signal lines to the electrodes 214 can be positioned in close proximity to avoid inductive and capacitive coupling.

Optical Beam Alignment Including the fiber optic switch 400 in a communication network makes reliability and availability extremely important. Therefore, the mirror surface 116 is always under the control of a biaxial servo, and the initial formation of the connection that couples light from one optical fiber 106 to another optical fiber 106 via the reflective switching module 100 is accurate.
And it becomes crucial that the properties of the bond be maintained for the duration of the connection. FIG. 26
And 26a, all port cards 406 have the ability to monitor the precise alignment of each pair of mirror surfaces 116 with respect to the light entering the fiber optic switch 400 or the light generated by one of the light sources 422. There is.

The fiber optic switch 400 takes advantage of this capability of the port card 406 to facilitate optical alignment of the mirror surfaces 116 of each pair and thus between the pair of optical fibers 106 connected to the reflective switching module 100. Monitor binding properties.
To monitor its coupling characteristics, the fiber optic switch 400 tilts each mirror surface 116 in the pair slightly from the orientation specified by the orientation signal value stored in the lookup 452, ie dithers both mirror surfaces 116. At the same time as (confusing), the intensity of the light beam 108 coupled between these two optical fibers 106 is monitored. Generally, in order to monitor the intensity of the optical beam 108 coupled between the two optical fibers 106, it is necessary that two of the at least 36 port cards 406 included in the optical fiber switch 400 have the same port. The process must be at least managed by the supervisory processor 436 shown in FIG. Thus, whenever an optical alignment of a pair of mirror surfaces 116 is needed or useful, the DSP 465 (FIG. 27b) included in each of the involved port cards 406.
The supervisory processor 436 then sends the appropriate commands via the data communication link 438 and the RS232 port 502 on each of the port cards 406. In response to a command sent from the monitoring processor 436, D is sent to the two DACs 467 provided in the two-axis servo 454.
The SP 465 sends coordinate data, which slightly tilts the mirror surface 116 whose direction is controlled by the biaxial servo 454. This change in direction changes the incidence of the light beam 108 on the lens 112 associated with the light output fiber 106, so that the amount of light coupled to the associated optical fiber 106 changes. This change in light coupled into the optical fiber 106 is transmitted to the port card 40 through the directional coupler 424 through which the outgoing light passes.
6 to the photodetector 426. To enable detection of this light change, a computer program executed by DSP 465 obtains the light intensity from an analog-to-digital converter (ADC) 504 coupled to a photodetector 426, as shown in FIG. 27b. To do. The DSP 465 on the port card 406 or the supervisory processor 436 or both fiber optic switches 400 analyzes this light intensity data to identify two mirror surfaces 116 for coupling the light beam 108 into a coupling between the two optical fibers 106. Ensure accurate alignment.

After accurate optical alignment of the mirror surface 116 is completed, the fiber optic switch 400 confirms that the light from the incoming optical fiber 106 is coupled to the appropriate outgoing optical fiber 106 via the reflective switching module 100. Incoming light beam 1
This is confirmed by dithering only the mirror surface 116 on which 08 is first incident.
If the reflective switching module 100 is properly aligned to couple light between a particular pair of optical fibers 106, the modulation from the incoming light beam 108 caused by dithering this particular mirror surface 116. Must appear only on the correct output fiber 106, not on any other optical fiber 106.

After the optical alignment of the pair of mirror surfaces 116 is completed and it is confirmed that the incoming light is coupled to the appropriate optical fiber 106 via the reflection switching module 100 as described above, the optical fiber switch 400. Uses the ability to dither the orientation of mirror surface 116 to periodically monitor (inspect) the properties of the bond. A computer program executed by monitoring processor 436 optionally updates the angular coordinate data stored in lookup 452 using the angular coordinates thus collected,
Further, a log of such data may be stored so that long-term reliability analysis of the optical fiber switch 400 can be performed.

[0132] The availability view 28a of industrial, used on the side 102a and 102b in place of convergence block 152 and the optical fiber collimator assembly 134, showing another specific example structure for receiving and fixing the optical fiber 106. In the structure shown in FIG. 28 a, a fixing plate 602 finely processed from silicon fixes the optical fiber 106. The end portions 104 of the optical fiber 106 protruding from the finely processed adjusting plate 604 made of silicon are adjusted so that the adjusting plate 604 can be adjusted horizontally and vertically, and then these end portions 104 are fixed to the adjusting position. The fixing plate 602 is 1.0 to 2.0 mm by using the Bosch strong RIE method.
An array of holes 606 formed by etching thick silicon penetrates through. These holes 606 are 100 to 125 microns in diameter, which is only a few microns larger than the optical fiber 106, to match the outer diameter of a conventional optical fiber 106. Fixed plate 602
If is required to be greater than 1.0-2.0 mm, two or more plates are juxtaposed and dynamically aligned using V-grooves and rods. After alignment, two or more juxtaposed fixing plates 602 are glued.

The holes 606 position the optical fibers 106 relative to each other with an accuracy within a few microns. By setting the depth: diameter ratio of the hole 606 to be high, for example, 10: 1 or more, it becomes easy to fix the optical fiber 106 in the length direction. Using anisotropic etching to form a pyramid-shaped entrance, only one of which is shown in Figure 28a, on one side of the fixed plate 602 facilitates insertion of the optical fiber 106 into the hole 606.

The hole 606 may be formed as a right cylinder, but may have a complex cylindrical contour as shown in Figure 28b. The hole 606 is formed by RIE or wet etching so that the cantilever 612 provides a contour that projects into the hole 606.
The position of the cantilever 612 with respect to the rest of the hole 606 is a position where the cantilever 612 bends slightly when the optical fiber 106 is inserted. In this way, the cantilever 612 holds the optical fiber 106 firmly in the wall of the hole 606 and allows the optical fiber 106 to slide along the length of the hole 606. Incorporate other more complex structures into the hole 606 to allow the optical fiber 1 to fit into the hole 606.
06 may be fixed. For example, a contour as shown in FIG. 28b may be formed in a part of each hole 606, and the rest may be aligned and etched from the opposite side of the fixing plate 602 to be molded as a right cylinder.

After the fixing plate 602 is manufactured, the optical fiber 106 is inserted into all the holes 606,
All the optical fibers 106 are made to project equally from the fixing plate 602 by several millimeters, for example, 0.5 to 3.0 mm. When the optical fiber 106 is thus projected from the fixing plate 602, the optical fiber 106 is easily bent. To ensure that all the optical fibers 106 project equally during assembly, the ends of the optical fibers 106 can be pressed against a stop. The optical fiber 106 may be fixed to the fixing plate 602 by adhesion or soldering, or may be simply held by frictional engagement with the cantilever 612.

As best shown in FIG. 28 c, the adjusting plate 604 has an array of XY micro stage stages 622 formed by etching through silicon of 1.0 to 2.0 mm thickness using the Bosch strong RIE method. To be equipped. Each microstage 622 is provided with a hole 624 suitable for receiving the end 104 of the optical fiber 106 projecting through the fixed plate 602. The spacing between the holes 624 through the adjustment plate 604 is equal to that through the fixed plate 602, and the holes 624 may have the contour shown in FIG. 28b. Each optical fiber 106 is slid into the hole 624.

FIG. 29 shows in detail one of the XY micro stage 622 provided on the adjusting plate 604. A similar monolithic silicon XY stage is described in U.S. Pat. No. 5,861,549, issued Jan. 19, 1999 (the '549 patent). Figure 29a shows that microstage 622 is integrally formed from a silicon substrate using RIE etching. The outer base 632 surrounding the XY microstage 622 is R
ev. SCI, Instrum. , 59, p. 67, 1988 Teague
It is connected to four flexures 636 of the type described by et al. Four similar flexures 642 connect the Y-axis stage 634 to the X-axis stage 644. The flexures 636 and 642 are of the quasi-deflection type and therefore extend properly due to the assumed XY motion for the hole 624. The XY microstage 622 moves and positions the end 104 of the optical fiber 106 by a small distance to allow the flexures 636 and 6 to move.
It suffices that it has the ability to prevent undue stress on 42. Other configurations for the flexures 636 and 642, such as those described in the 549 patent, may also be used.

The XY microstage 622 has no actuator, and the Y-axis stage 634
May be secured to the outer base 632 with a metal such as gold, kovar, tungsten, molybdenum, ribbon or wire linkage 652. Similarly, the X-axis stage 644 may be fixed to the Y-axis stage 634 with a metal ribbon or wire linkage 654. For the linkages 652 and 654, materials with a coefficient of thermal expansion similar to or close to that of silicon are selected. However,
If the linkages 652 and 654 are as short as 100 microns, for example, even if the coefficient of thermal expansion difference between silicon and metal (for example, aluminum) is 20 ppm, the outer base 63
The movement of the X-axis stage 644 with respect to 2 will be only about 20Å / ° C.
Metals other than aluminum have even higher thermal stability.

When adjusting the XY microstage 622, the linkages 652 and 654 are first bonded to the Y-axis stage 634 and the X-axis stage 644, respectively. By simultaneously pulling the metal linkages 652 and 654 while looking at the end 104 of the optical fiber 106 with a microscope, the X-axis stage 644 can be moved along both the X and Y axes to position the end 104 at a specific position. . Once the X-axis stage 644 has moved to properly position the end 104, the linkages 652 and 654 are glued or spot welded together to secure.

The XY microstage 622 may be provided with a lever 622 shown in FIG. 29C, and the movement of the X-axis stage 644 may be made smaller than the movement of the distal end 664 of the XY microstage 622. In the XY microstage 622 shown in the figure, the stages 634 and 644 are formed by etching to obtain the lever 622 protruding from the Y-axis stage 634 like a cantilever. First, the linkage 654 is the X-axis stage 6
Adhere to both 44 and lever 622. Similar linkage 666 to lever 622
Is fixed to the end portion farther from the joint with the Y-axis stage 634. X-axis stage 6
Once 44 has moved to properly position end 104, linkage 666 is as before.
Are bonded or spot-welded to the Y-axis stage 634. Alternatively, as shown in FIG. 29c, the linkage 654 is omitted from the XY microstage 622 and replaced by a well-known flexible thumbtack (push pin), which is between the X-axis stage 644 and the lever 622 protruding from the Y-axis stage 634. You may make it connect. Both ends of the flexible thumbtack are connected to the X-axis stage 644 and the lever 622 by flexures 674, respectively. A specific example of the XY microstage 622 shown in FIG. 29c is a linkage 666.
Only one is required to secure the X-axis stage 644 when the end 104 of the optical fiber 106 is in its particular position. Further, the flexible push pin 67
2 can push or pull the X-axis stage 644, the X-axis stage 6
The movement of 44 is bidirectional.

Although the above description regarding the lever 622 was directed only to the X-axis movement of the X-axis stage 644, a similar lever was incorporated into the outer base 632 to allow the Y-axis stage 634 and the X-axis stage relative to the outer base 632. It is immediately apparent that the 644 can be moved in the Y axis.

As described above, according to the XY micro stage 622, the end portion 104 of the optical fiber 106 can be fixed and adjusted along the X and Y axes thereof. However, in order to properly focus the lens 112 with respect to the end 104 of the optical fiber 106, it is also necessary to relatively move either the end 104 or the lens 112 along the axis 144. The distance between the end 104 of the optical fiber 106 and the lens 112 can be adjusted by various methods. Bright, et al. , SPIE
Proc. , Vol. 2687, p. At 34, a polysilicon mirror that moves like a piston is described. This mirror is manufactured on a substrate and can be electrostatically displaced at right angles to the substrate.

FIG. 30 a illustrates a plano-convex lens 112 that is micromachined from an SOI wafer using RIE etching, fabricated on a substrate, and electrostatically displaceable along an axis 144 at right angles to the substrate. To electrostatically displace the lens 112 along the axis 144, the lens 112 is supported by three V-shaped flexures 682 from the surrounding device silicon layer 166 side of the wafer 162, as shown in FIG. 30b. Each of the flexures 682, each of which partially covers the lens 112, is connected to the surrounding device silicon layer 166 at one end and to the lens 112 at the other end. The assembly is all made as one unitary silicon structure, except for the deflection electrode 684, which is located to the right of the lens 112 in FIG. 30a and is electrically isolated from the wafer 162. The electrostatic attraction created between the electrode 684 and the flexure 682 and lens 112 by applying a potential between the electrode 684 and the device silicon layer 166 causes the lens 112 to move along the axis 144 along the electrode 68.
Pull toward 4.

Silicon lenses suitable for IR fiber optic transmission are commercially available and may be suitable sources for use in this invention. Therefore, a small, commercially available microlens may be placed in the cavity etched in the thin film supported by flexure 682. Alternatively, RIE may be used to form the lens 112 while the flexure 682 is formed. Another alternative method is to first turn the lens 112 with diamond and then protect it from etching while using RIE to form the flexure 682. Yet another alternative method is to first use RIE to form the flexure 682 while protecting the portion where the lens 112 is formed and then diamond turn the lens. After the lens 112 and the flexure 682 are formed by these methods, the underlying wafer 162 is removed by anisotropic etching to expose the silicon oxide increase. The back side of the lens 112 manufactured in this way is optically flat.

Instead of electrostatic drive, the lens 112 can be moved electromagnetically along the axis. As shown in FIG. 30c, the electrode 684 located close to the lens 112 in the example of FIG. 30a is replaced by a permanent magnet 692 oriented in a magnetic field parallel to the axis 144 of the lens 112. A coil 694 also surrounds the lens 112. The current leads from the coil 694 are drawn through the flexure 682, preferably symmetrically, to the device silicon layer 166, ensuring a linear displacement of the lens 112.
Depending on the direction of the current passed through the coil 694, the lens 112 moves toward or away from the end 104 of the optical fiber 106.

Similarly, magnetic force rather than electrostatic force may be used to rotate plate 184 at least preferably about the rotational axis set by torsional flexure hinge 176 or torsion bar hinge 182. 31a and 31b, several magnets are shown, all oriented in the same direction along the strip of the torsion scanner 172. Thus, the individual magnetic fields represented by arrows 697 are oriented in the same direction and reinforce each other. The torsion scanner 172 also includes a coil 698 disposed on its inner moving frame 178 through which current flows when rotating the plate 184. By using the configuration of the twist scanner 172, the inner moving frame 1
The electrode 214 facing 78 can be removed from the substrate 212. Generally, the magnet 6
Where 96 and coil 698 are present, substrate 212 is provided with a cavity adjacent inner moving frame 178, as described in U.S. Patent No. 6044705 issued Apr. 4, 2000. By providing such a cavity, the inner moving frame 178 can be largely rotated around the axis set by the torsion bending hinge 176. Figure 31
As shown in FIG. 5b, the magnet 696 is typically used for the mirror surface 1 when the light beam 108 has a large angle.
It has a trapezoidal cross section so as to hit 16. Alternatively, Figures 31c and 31d
The magnets 696 may be arranged linearly along both sides of the torsion scanner 172, as shown in FIG. By configuring the torsion scanner 172 and the magnet 696 in this way, it is possible to improve the magnetization coefficient of these magnets and to strengthen the magnetic field.

In many communication applications of fiber optic switch 400, the light reaching fiber optic switch 400 has already passed through a routing wavelength demultiplexer, which is typically in the form of integrated circuit chips. A significant cost in manufacturing a routing wavelength demultiplexer is often the connection from its planar circuit to the output fiber. If the reflection switching module 100 of the optical fiber switch 400 is appropriately configured, it is not necessary to connect the routing wavelength demultiplexer and the optical fiber, and the output beam from the routing wavelength demultiplexer is reflected in the free space. It only has to be connected to 100 lenses, namely the lens 112 with antireflection coating.

FIG. 32 shows a configuration in which the routing wavelength demultiplexer 702 is provided with several demultiplexed planar waveguides 704. This demultiplexed planar waveguide 70
At 4, the light beam 108 is emitted towards the lens 112 facing it, thereby avoiding the need to couple the routing wavelength demultiplexer 702 to an optical fiber. The substrate 706 of the routing wavelength demultiplexer 702 holding the demultiplexed planar waveguide 704 may be placed in close proximity to the lens 112 to provide the incoming light beam 108 to the reflective switching module 100.
Similarly, where the outgoing light beam 108 leaves the reflective switching module 100, the lens 112 directs the optical beam 108 directly into the demultiplexed planar waveguide 704.
From which the light beam may be multiplexed into one or several output fibers. By providing extra input and output holes 154 in the converging block 152 used with the wavelength converter, the optical fiber switch 400 wavelength modulates light received from any of the optical fibers 106 coupled to the optical fiber switch 400. It can be performed.

In many applications of fiber optic switch 400, wavelength conversion is desirable. Figure 3
Wavelength conversion can be easily accomplished by forming a grating on the plate 184 of the torsion scanner 172, as shown in FIGS. 3a and 33b. Lens 712
And a laser diode 714 together with a grating 712 are disclosed in US Pat.
Littrow cavities [Lit similar to those described in 52788687 and 57771252.
‘Trow cavities’. Within the Littrow cavity, a grating 712 supported by a rotatable plate 184 reflects the first-order diffracted beam back to the laser diode 714, thereby creating a laser-producing optical resonator at the back facet of the laser diode 714. Beamsplitter 722 directs the zero-order diffracted output beam 724 to wavelength locker 726, as is well known. Therefore, rotation of plate 184, which carries grating 712, changes the wavelength of light in the output beam. Feedback from the wavelength locker 726 can be used to control the rotation of the plate 184 and thereby select a particular wavelength of 724 in the output beam.

In the example of FIG. 34, the wavelength of light propagating along the optical fiber 106 is measured using the structure of the grating 712 carried by the plate 184. The light extracted from the optical fiber 106 by the directional coupler 424 or the bent fiber tap is reflected by the lens 742.
Incident on the grating 712. Although the diffracted light from the grating 712, for example, the first-order diffracted light enters the photodetector 744, the latter may include a small collimating lens. While rotating the grating 712, the output signal generated by the photodetector 744 and the signal generated by the torsion sensor 192 in the torsion scanner 172 are monitored at that time to generate a spectrum of light propagating along the optical fiber 106. . The photodetector 744 can be physically very small and therefore very inexpensive. In contrast, diode arrays that respond well to infrared light are relatively expensive.

Although the present invention has been described above with reference to presently preferred embodiments, it should be understood that such disclosure is purely illustrative and should not be construed in a limiting sense. Accordingly, various modifications, arrangements and / or alternative uses of the invention will be apparent to those skilled in the art upon reading the above disclosure without departing from the spirit and scope of the invention. Therefore,
It is intended that the claims set forth below be construed to cover all changes, modifications or alternatives falling within the true spirit and scope of the invention.

[Brief description of drawings]

FIG. 1 is a block diagram showing a three-stage fully non-blocking optical fiber switch according to a conventional technique.

FIG. 2 is a plan view ray trace diagram showing the propagation of a light beam through a trapezoidal free space focusing NxN reflection switching module according to the present invention.

3 is a plan or elevational schematic diagram showing a single light beam propagating between sides A and B of the trapezoidal free-space focusing NxN reflective switching module shown in FIG. 2 according to the present invention.

FIG. 4a is a perspective ray tracing diagram illustrating propagation of a light beam through an alternative embodiment rectangular free-space focusing NxN reflection switching module according to the present invention.

4b is a plan view ray trace diagram illustrating the propagation of a focused light beam through the rectangular reflective switching module shown in FIG. 4a in accordance with the present invention.

FIG. 5 is a plan view ray tracing diagram illustrating the propagation of a light beam through a polygonal free space focusing NxN reflection switching module according to the present invention.

FIG. 6 is a plan view ray trace diagram showing the propagation of a light beam through a trapezoidal free-space focusing reflection switching module according to the invention, such that the light beam is coupled between pairs of arbitrarily chosen optical fibers. Is.

6a is a collection according to the invention arranged as a V-shaped array of light beam deflectors such that the light beam is coupled between pairs of arbitrarily chosen optical fibers, similar to the switching module of FIG. FIG. 6 is a plan view ray trace diagram illustrating propagation of a light beam through a reflective switching module.

7 is a plan ray trace diagram showing the propagation of a light beam through another trapezoidal free-space focusing NxN reflection switching module according to the invention, which is more compact than the NxN reflection switching module shown in FIG.

FIG. 8a is an elevational view showing a more preferred cylindrical microlens suitable for use in an NxN reflective switching module.

FIG. 8b is an elevational view showing a microlens suitable for use in an NxN reflective switching module, with a narrower lens-to-fiber spacing.

9 is a partial cross-sectional elevational view showing a light collection block on both side A and side B of the NxN reflective switching module shown in FIG. 7 that receives a tapered fiber optic collimator assembly.

FIG. 10 is a partial cross-sectional plan view showing the light collection block shown in FIG. 9 receiving a tapered fiber optic collimator assembly.

FIG. 10a is a partial cross-sectional plan view showing an alternative focusing block with adjustable lens position and orientation.

10b is a cross-sectional elevation view of an alternative light collecting block taken along line 10a-10a of FIG. 10a.

FIG. 11 is a partial cross-sectional elevation view showing a microlens suitable for use in an NxN reflective switching module that simultaneously switches light carried by a duplex pair of optical fibers.

FIG. 12 is an elevational view showing a preferred type of silicon wafer substrate used to fabricate a torsion scanner.

FIG. 13 is a plan view showing a two-dimensional electrostatic bias torsion scanner particularly suitable for use in reflective switching modules such as those shown in FIGS. 2, 4a, 4b, 5, 6 and 7.

14a is an enlarged plan view of the torsion flexure hinge used in the torsion scanner taken along line 14a-14a of FIG. 13. FIG.

14b is an enlarged plan view of the slotted twist bar hinge used in the twist scanner taken along line 14b-14b of FIG. 13. FIG.

FIG. 15 is a torsion scanner disposed on an insulating substrate with electrodes attached, a schematic cross-sectional elevation showing the light beam reflecting off a mirror surface located on the back side of the device layer. It is a figure.

15a, 15b are alternative plan views of a portion of the insulative substrate and electrodes taken along line 15a / 15b-15a / 15b of FIG.

[16a] FIG. 16a is an elevational view of a strip of a torsion scanner suitable for use in a reflective switching module as shown in FIGS. 2, 4a, 4b, 5, 6 and 7.

FIG. 16b is a cross-sectional plan view taken along line 16a-16b of FIG. 16a showing overlapping of adjacent strips of a torsion scanner to reduce the horizontal distance between adjacent strips.

16c is an elevational view showing a preferred example of a torsion scanner strip suitable for use in reflective switching modules such as those shown in FIGS. 2, 4a, 4b, 5, 6, 6a and 7. FIG.

16d is a cross-sectional plan view showing an example priority strip of a torsion scanner taken along line 16d-16d of FIG. 16c.

16e is a line 16 of FIG. 16a showing the strip alignment of the torsion scanner shown in FIG. 16c.
It is a sectional top view taken along with e-16e.

17a shows a vertical offset strip of a torsion scanner with the optical fibers more closely packed in a reflective switching module as shown in FIGS. 2, 4a, 4b, 5, 6 and 7. FIG. It is a top view.

FIG. 17b: Plane showing staggered row and column misalignment of the twist scanner, which can be used if all of the twist scanners are made as a single monolithic array rather than strips. It is a figure.

FIG. 18a: The outer torsional flexure hinge is bracingly oriented with respect to the outer frame of the scanner,
FIG. 6 is a plan view of an alternative embodiment torsion scanner.

18b is a plan view of an array of torsion scanners of the type shown in FIG. 18a.

FIG. 19a is a plan view of another embodiment of a torsion scanner with the inner torsion flexure hinge oriented along the diagonal of the non-square mirror plate of the scanner.

19b is an embodiment of the torsion scanner shown in FIG. 19a, in which both pairs of torsion-deflecting hinges are properly oriented with respect to the silicon crystal axis, within which the torsion sensor has optimum characteristics. It is a top view showing what was produced by.

20a is an elevational view showing a close-up arrangement of the torsion scanner shown in FIG. 18a suitable for inclusion in a reflective switching module such as that shown in FIGS. 2, 4a, 4b, 5, 6 and 7. FIG.

FIG. 20b is an elevational view showing a close-up of the torsion scanner shown in FIG. 19a suitable for inclusion in a reflective switching module as shown in FIGS. 2, 4a, 4b, 5, 6 and 7.

FIG. 21 is an alternative embodiment strip of a twist scanner fixed to a substrate, also holding the mirror strip, with the collimator lens and the end of the optical fiber positioned proximate to the mirror surface on the twist scanner. FIG. 3 is a schematic sectional elevation view showing the above.

21a is a schematic elevational view showing the strip of the torsion scanner of FIG. 21 arranged to provide one-dimensional focusing. FIG.

FIG. 21b is a schematic elevational view showing the fiber optic collimator assembly arranged to provide one-dimensional light collection in combination with the one-dimensional light collection of FIG. 21a.

FIG. 22a is a front elevational view of a twist scanner flip chip strip adhered to a substrate.

22b is a cross-sectional side elevational view of a strip of a twist scanner flip chip in close contact with a substrate taken along line 22b-22b of FIG. 22a.

22c is a top view of a strip of a flip-chip torsional scanner that is affixed to a substrate, taken along line 22c-22c of FIG. 22a.

FIG. 22d is a cross-sectional side elevational view of a twist scanner flip-chip strip adhered to a channeled silicon substrate.

FIG. 22e is a cross-sectional side elevational view showing a portion of the surface of a torsion scanner with troughs formed to enhance the bond to the substrate.

22f shows a torsion scanner strip with a spacer between the substrate and FIG.
2 is a sectional side elevational view similar to that of FIG.

FIG. 23 is a ray tracing diagram showing the scattering of light from multiple parts of the torsion scanner surrounding its mirror surface.

FIG. 24 is a system level block diagram illustrating a reflective switching module as shown in FIGS. 2, 4a, 4b, 5, 6 and 7.

FIG. 25   1 is a perspective view showing a modular optical fiber switch according to the present invention.

26 is a general block diagram of the modular optical fiber switch of FIG. 25 including a port card and a reflective switching module.

FIG. 26a is a diagram showing one embodiment of a photodetector that can be used for an optical alignment servo that accurately aligns a pair of mirrors included in a reflection switching module.

FIG. 26b is a diagram showing an optical compound detector that can be used for an optical alignment servo that accurately aligns a pair of mirrors included in a reflection switching module.

FIG. 26c is a schematic diagram showing the use of bent fiber taps on a port card to extract light from an optical fiber for alignment and other diagnostic purposes.

16d is an elevation view of the bent fiber tap taken along line 26d-26d of FIG. 26c.

Figure 27a: Accurate alignment of the mirrors of the reflective switching module of the modular fiber optic switch shown in Figure 25, which is one of the reflective switching modules as shown in Figures 2, 4a, 4b, 5, 6 and 7. FIG. 3 is a block diagram showing a servo system for ensuring the above.

27b is a block diagram showing an X-axis or Y-axis channel of a two-axis servo provided in the servo system shown in FIG. 27a.

FIG. 27c is a block diagram illustrating several different pairs of torsion scanner electrodes 214 sharing a single channel for one biaxial servo.

FIG. 27d is a block diagram illustrating a circuit for inducing controlled rotation of a torsion scanner using an AC drive voltage.

27e and 27f are waveform diagrams showing the voltage applied between the electrodes of the torsion scanner and the mirror plate.

Figure 28a is an alternative embodiment plate for receiving and securing an array of optical fibers.
It is a fragmentary sectional elevation view which shows a structure.

28b is an elevational view showing the profile of one type of hole formed through one of the plates taken along line 28-28b of FIG. 28a.

28c is an elevational view showing an array of XY microstages formed through one of the plates, taken along line 28-28b in FIG. 28a.

Figure 29a is an elevational view of the XY microstage taken along line 29a-29a of Figure 28c.

29b, 29c are elevation views of a portion of another embodiment of an XY microstage taken along line 29b / 29c-29b / 29c of FIG. 29a.

FIG. 30a is a partial cross-sectional view of a lens micromachined from a silicon substrate that is electrostatically biased and moves along its axis.

FIG. 30b is an elevation view of the silicon microfabricated lens taken along line 30b-30b of FIG. 30a.

FIG. 30c is a partial cross-sectional view of a lens, like that shown in FIG. 30a, which has been micromachined from a silicon substrate and is electromagnetically biased to move along its axis.

Figure 31a. It is a top view which shows one structure for using a magnetic force to rotate a torsion scanner.

31b is an elevational view of the magnet used therein taken along line 31b-31b of FIG. 31a.

FIG. 31c is a plan view showing another configuration for using magnetic force to rotate the scanner.

31d is an elevational view of the magnet used therein taken along line 31d-31d of FIG. 31c.

FIG. 32 shows a light beam from a routing wavelength demultiplexer shown in FIGS.
Figure 8b is a side view showing a direct connection to one of the reflective switching modules as shown in Figures 4b, 5, 6, 6a and 7.

Figures 33a and 33b are schematic diagrams showing a Littrow cavity formed by a diffraction grating formed on a 2D torsion scanner together with a laser diode, and its application, wavelength conversion that can be freely used for telecommunications. FIG.

FIG. 34 is a schematic diagram showing the use of a twist scanner adapted to carry a diffraction grating for monitoring the wavelength of light propagating along an optical fiber.

[Explanation of symbols]

100 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Reflection type switching module 102a, 1021b ... 104 ... 106 ・ ・ ・ ・ ・ ・ ・ ・ ・ Optical fiber 108 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Light beam 112 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Lens 116a, 116b ... Mirror surface 118a, 118b ... Set 120 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mirror 122b, 122b ... 132 ... 134 ..... Optical fiber collimator assembly 136 ... 138 ... 142 ······ Convex 144 ... Axis 146 ... Ferrule 152 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Convergence block 154 ... 162 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wafer 164 ..................... Silicon dioxide layer 166 ... Single crystal silicon layer, device silicon layer 168 ..................... Single crystal silicon layer, handle silicon layer 169 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Front side 170 ... 172 ........ Torsion scanner 174 ........... Outside reference frame 176 ... Torsion-deflection hinge 178 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inward moving frame 182 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Torsion bar hinge 184 ・ ・ ・ ・ ・ ・ Plate 192a, 192b ..... torsion sensor 194a, 194b ......... Sensor current pad 196 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Merking metal conductor 198a, 198b ... ・ ・ ・ ・ ・ Inner hinge sensor pad 202a, 202b ... Inside hinge sensor pad 204 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Groove 212 ······ Base (substrate) 214 ... Electrode 216 ... 218 ... Reinforcement rib 219 ........ electrically insulating material 220 ・ ・ ・ ・ ・ ・ ・ ・ ・ Hole 222 ... 224 ... Support frame 226 ... Ribbon cable 228 ... Lead wire 232 .... 236a, 236b ......... Rotary shaft 242 ・ ・ ・ ・ ・ ・ ・ ・ ・ Base 244 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ X axis, Y axis 246 ... Rectangular field 262 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mirror strip 264 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Beam folding / deflecting assembly 272 ... 276 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Solder bump 282 ... 284 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Oxide layer 286 ... Polysilicon layer 288 ... 292 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Elastomer layer 294 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Polyimide + copper layer 298 ... Bump 302 ... 304 ... 312 ······· Antireflection layer 352 ... Environmental housing 353 ..................... Unsaturated micro dryer 354 ........ Wall 356 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Electrical feedthrough 400 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Optical fiber switch 402 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rack 404 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Double socket 406 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Port card 412, 414 ... 422 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Light source 424 ・ ・ ・ ・ ・ ・ ・ ・ ・ Directional coupler 426 ... Photodetector 432 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Drive / sensing / control electronics 436 ... Monitoring processor 438 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Data communication link 442 ... Connector 452 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Lookup (table) 454 ... 2-axis (dual) servo 462 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Current source 463 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Measurement amplifier 464 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Error amplifier 465 ... DSP 466 ..... RAM 467 ... DAC 472 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Integrator circuit 463 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Amplifier 474 ......... Resistance 475 ... Capacitor 476a, 476b ... ・ ・ ・ ・ ・ Adding amplifier 477 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inverting amplifier 478 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ High-voltage amplifier 482 ........... Telecom signal strength photodetector 484 ... Alignment photodetector 486 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Dichroic mirror 488 ... Telecom signal monitoring photodetector 492 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Silicon photodetector 494 ... Long wavelength photodetector 495 ... Bending fiber tap 502 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ RS232 port 504 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Analog-to-digital converter (DAC) 602 ........... Fixing plate 604 ... Adjusting plate 606 ... 608 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Entrance 612 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Cantilever 622 ... XY micro stage 624 ........ hole 632 ........... Outside base 634 ... Y-axis stage 636, 642 .... Flexible body 644 ........... X-axis stage 652, 654, 666 ... Linkage 664 ........ 674, 682 ... Flexible body 672 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pushpin 684 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Electrode 692 ........ Permanent magnet 694 ······ Coil 702 ........ Routing wavelength demultiplexer 704 ... Demultiplexer planar waveguide 706 ... Base material (substrate) 712 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Lattice 714 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Laser diode 722 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Beam splitter 724 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (zero-order diffraction) output beam 726 ・ ・ ・ ・ ・ ・ ・ ・ ・ Wavelength locker 732 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Incoming beam 734 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Gain medium 744 ... Photodetector

─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Clark, Stephen, M             United States California 94303 Pa             Ro Alto, Celia Way 986 (72) Inventor Schumann, Mark, Earl             94122, California, United States             Francisco, 9th Avenue             1550-2 (72) Inventor Slater, Timothy, Dee             94110, California, United States             Francisco, Folsom Story             To 3715 (72) Inventor Foster, Jack, Dee             Los Angeles, California, United States             Lutos, Renetta Court 856 (72) Inventor Carmes, Sam             94040, California, United States             Unten View, Latham Street             2250, Apt 10 F-term (reference) 2H037 AA01 BA32 CA38                 2H041 AA16 AA17 AB14 AC06 AZ02                       AZ05                 5K002 BA02 BA06 BA21 FA01 [Continued summary] (172) for connecting the optical fiber 08) between the optical fibers Orient the pair exactly.

Claims (53)

[Claims] 1. A fiber optic switching module suitable for receiving and securing an end of an optical fiber and emitting a quasi-parallel light beam into a free space optical path, each of which includes: A first group and a second group of collimator receivers, which respectively receive and fix the optical fiber collimator assembly, are located at both ends of the optical path and are separated from each other; First set and second set in a V shape
A pair of reflected light beam deflectors, and a mirror disposed along the optical path between the pair of light beam deflectors and into which a quasi-parallel light beam is incident, the first or second set of light beam deflectors Each of which is associated with one of the fiber optic collimator assemblies receivable by the collimator receiver, the quasi-parallel light beam emitted from the associated fiber optic collimator assembly impinging on a light beam deflector and reflecting. A quasi-parallel light beam positioned to be driven by the drive signal provided to the fiber optic switching module and directed to be emitted from the companion fiber optic collimator assembly. A light beam deflector which is reflected by the light beam deflector and is thereby provided with a pair of light beam deflectors. Selected by the issue,
When oriented, at least one quasi-parallel between a pair of fiber optic collimator assemblies, one fixed to one of the collimator receivers and the other fixed to another collimator receiver. A fiber optic switching module configured to establish a coupling of light beams. 2. The first group is provided with only one collimator receiver, and the second group
A group of remaining collimator receivers, one optical fiber collimator assembly that can be fixed to the single collimator receiver and an optical fiber collimator assembly that can be fixed to the second group of collimator receivers. The fiber optic switching module of claim 1, wherein the fiber optic switching module is configured to establish an optical connection with the other one. 3. The fiber optic switching module of claim 1, wherein the individual collimator receivers are conical in shape and are configured to receive a mating conical fiber optic collimator assembly. 4. The fiber optic switching module according to claim 1 , wherein an optical housing surrounds an optical path through which the light propagates. 5. The fiber optic switching module of claim 4, wherein the fiber optic switching module is configured to provide temperature regulation to maintain a stable operating environment of the fiber optic switching module. 6. The fiber optic switching module of claim 4, wherein the dry gas is allowed to flow through the environmental housing to prevent atmospheric air surrounding the environmental housing from entering the fiber optic switching module. 7. The fiber optic switching module of claim 4 configured to pressurize the environmental housing to prevent atmospheric air surrounding the environmental housing from entering the fiber optic switching module. 8. The fiber optic switching module of claim 4, wherein the environmental housing comprises an unsaturated micro dryer and is configured to prevent condensation within the fiber optic switching module. 9. The fiber optic switching module of claim 4, wherein the electrical feedthrough through which the drive signal flows is configured to extend through a wall of the environmental housing. 10. The fiber optic switching of claim 1 wherein the light beam deflector is configured to substantially converge in one dimension (1D) when reflected from the light beam deflector when not energized. module. 11. The fiber optic switching of claim 1 wherein the light beam deflector is configured to substantially converge in two dimensions (2D) when reflected from the light beam deflector when not energized. module. 12. The orientation of the collimator receiver converges to a first dimension and the orientation of the collimator receiver converges to a second dimension when the light beam deflector is not energized. 11. The optical fiber switching module according to item 11. 13. The first or second set of light beam deflectors when they are not energized, the light reflected therefrom is substantially convergent at a point located behind the bifurcation of both sets of light beam deflectors. The optical fiber switching module according to claim 1, wherein the optical fiber switching module is configured to: 14. The first or the second set of light beam deflectors when they are not energized, so that the light reflected from them is substantially converged at a point located at a branch point of both the light beam deflector sets. The optical fiber switching module according to claim 1, wherein the optical fiber switching module is configured as described above. 15. A first or second set of light beam deflectors that requires a maximum movement to reflect ## EQU1 ## to either the second set or the first set of beam deflectors has a non-biased orientation of such light beam deflectors. 2. The fiber optic switching module of claim 1, wherein the fiber optic switching module is configured to exhibit substantially equal rotation angles in a clockwise direction and a counterclockwise direction. 16. A first or a second set of optical beam deflectors which require a maximum movement to reflect a to either the second or the first set of beam deflectors are rotated about two non-parallel axes. And configured to exhibit rotational angles substantially equal to the clockwise and counterclockwise directions about at least one of the axes from the biased orientation of the light beam deflector. Optical fiber switching module. 17. A first or second set of light beam deflectors that requires a maximum movement to reflect ## EQU1 ## to either the second set or the first set of beam deflectors, wherein the unbiased orientation of such light beam deflectors is 2. The fiber optic switching module of claim 1 configured to exhibit substantially equal bipolar rotation angles from. 18. A first or a second set of optical beam deflectors which require a maximum movement to reflect ## EQU1 ## to either the second or the first set of beam deflectors, rotating about two non-parallel axes. And a fiber optic switching module according to claim 1 configured to exhibit substantially equal bipolar rotation angles about at least one of the axes from the biased orientation of the light beam deflector. 19. A first or second set of light beam deflectors that requires a maximum movement to reflect to either the second set or the first set of beam deflectors is an unbiased orientation of such light beam deflectors. 2. The fiber optic switching module of claim 1, wherein the fiber optic switching module is configured to exhibit a substantially minimum rotation angle. 20. The fiber optic switching module of claim 1, wherein the orientation of only the collimator receiver is configured to converge. 21. The optical fiber switching module according to claim 1, wherein the orientation of only the light beam deflector when deenergized is configured to converge. 22. The drive signal provided to the fiber optic switching module for activating the orientation of each light beam deflector is configured to be responsive to a signal generated by an orientation sensor coupled to the light beam deflector. Item 1. The optical fiber switching module according to Item 1. 23. The drive signal provided to the fiber optic switching module for activating the orientation of each deflector is responsive to a signal generated by an orientation sensor independent of a light beam capable of being reflected from the light beam deflector. The optical fiber switching module according to claim 1, wherein 24. The light beam deflector is supported by a torsion hinge from the frame side, and each frame, the torsion hinge and the light beam deflector are made of single crystal silicon. 1. The optical fiber switching module described in 1. 25. An optical fiber switching module comprising: (a) at each end of a free space optical path of an optical fiber receiver, each of which is suitable for receiving and securing one end of an optical fiber. First group and second group separated from each other
Group, and (b) one lens is fixed to each of the optical fiber receivers of the first group and the second group, and one end of an optical fiber that can be fixed to the optical fiber receiver faces the lens fixed thereto. A lens suitable for receiving each of the lenses can be emitted from opposite ends of an optical fiber and emitting a quasi-parallel light beam into an optical path of a fiber optic switching module; and (c) the two fiber optic receivers. A first set and a second set of reflected light beam deflectors, both of which are arranged in the optical path between the groups; A beam incident mirror, each of the first or second sets of light beam deflectors being associated with one of the lenses fixed to each of the optical fiber receivers. A quasi-parallel light beam that can be emitted from the light beam deflector,
A quasi-parallel light beam positioned to be reflected and capable of being emitted from the follower lens when energized by a drive signal supplied to the optical fiber switching module, the quasi-parallel light beam also Two or a first set of light beam deflectors, which may be oriented to reflect out of a selected one of the light beam deflectors, whereby a pair of light beam deflectors is provided. Selectable by drive signal,
When oriented, at least one quasi-parallel light beam between a pair of lenses, one of which is fixed to one of the optical fiber receivers and the other of which is fixed to another optical fiber receiver. A fiber optic switching module configured to establish a connection. 26. The first group is provided with only one optical fiber receiver, the second group is provided with the remaining optical fiber receivers, and one lens is fixed to the single optical fiber receiver. 26. The fiber optic switching module of claim 25, wherein the fiber optic switching module is configured to establish an optical connection with one of the lenses fixed to the second group of fiber optic receivers. 27. The fiber optic switching module of claim 25, further configured to include an environmental housing surrounding an optical path through which the light propagates. 28. The environmental housing is configured to provide temperature regulation to maintain a stable operating environment for the fiber optic switching module.
The optical fiber switching module described in 1. 29. The fiber optic switching module of claim 27, wherein the fiber optic switching module is configured to allow a dry gas to flow through the environmental housing to prevent atmospheric air surrounding the environmental housing from entering the fiber optic switching module. 30. The fiber optic switching module of claim 27, wherein the environment housing is pressurized to prevent atmospheric air surrounding the environment housing from entering the fiber optic switching module. 31. The environmental housing comprises an unsaturated microdryer and is configured to prevent condensation within the fiber optic switching module.
Optical fiber switching module. 32. The fiber optic switching module of claim 27, wherein the electrical feedthrough for the drive signal is configured to extend through a wall of the environmental housing. 33. The fiber optic switching module of claim 25, wherein the light beam deflector is configured to substantially converge in 1D when reflected from the light beam deflector when not energized. 34. The fiber optic switching module of claim 25, wherein the light beam deflector is configured to substantially converge in 2D when reflected from the light beam deflector when not energized. 35. The fiber optic receiver orientation is configured to focus in a first dimension, and the orientation is focused in a second dimension when the light beam deflector is not energized. Item 35. The optical fiber switching module according to Item 34. 36. When the first and second sets of light beam deflectors are not energized, the light reflected from them is located behind the bifurcation of the second or first set of light beam deflectors. 26. The fiber optic switching module of claim 25, configured to substantially converge at a point. 37. When the first and second sets of light beam deflectors are not energized, the light reflected from the first and second sets is converged at a point located at the branch point of both sets of light beam deflectors. 26. The fiber optic switching module of claim 25. 38. A first or second set of light beam deflectors which requires a maximum movement to reflect to either the second set or the first set of beam deflectors has a non-biased orientation of such light beam deflectors. 26. The optical fiber of claim 25, wherein the optical fiber is configured to exhibit substantially equal rotation angles in a clockwise direction and a counterclockwise direction.
Switching module. 39. A first or a second set of optical beam deflectors which require a maximum movement to reflect ## EQU1 ## to either the second or the first set of beam deflectors rotates about two non-parallel axes. 26, and configured to exhibit substantially equal rotation angles in clockwise and counterclockwise directions about at least one of the axes from the unbiased orientation of such a light beam deflector. Optical fiber switching module. 40. A first or second set of light beam deflectors that requires a maximum movement to reflect ## EQU1 ## to either the second set or the first set of beam deflectors, wherein the light beam deflector is in a non-biased orientation. 26. The fiber optic switching module of claim 25, configured to exhibit substantially equal bipolar rotation angles from. 41. A first or a second set of optical beam deflectors, which requires a maximum movement to reflect ## EQU1 ## to either the second or the first set of beam deflectors, rotates about two non-parallel axes. 26. The fiber optic switching module of claim 25, further configured to exhibit substantially equal bipolar rotation angles about at least one of the axes from the unbiased orientation of the light beam deflector. 42. A first or second set of light beam deflectors that requires a maximum movement to reflect ## EQU1 ## to either the second set or the first set of beam deflectors is an unbiased orientation of such light beam deflectors. 26. The fiber optic switching module of claim 25, wherein the fiber optic switching module is configured to exhibit a substantially minimum angle of rotation. 43. The fiber optic switching module of claim 25, wherein the orientations of only the fiber optic receiver and the lens are configured to achieve convergence of. 44. The fiber optic switching module of claim 25, wherein the orientation of only the light beam deflector when deenergized is configured to converge. 45. The drive signal provided to the fiber optic switching module for activating the orientation of each light beam deflector is configured to be responsive to a signal generated by an orientation sensor coupled to the light beam deflector. Item 25. The optical fiber switching module according to Item 25. 46. The drive signal provided to the fiber optic switching module for activating the orientation of each light beam deflector is responsive to a signal generated by an orientation sensor independent of the light beam deflector's reflectivity. 26. The fiber optic switching module of claim 25. 47. The light beam deflector is supported by a torsion hinge from the frame side, and each frame, the torsion hinge and the light beam deflector are made of single crystal silicon. 25. The optical fiber switching module described in 25. 48. An end of an optical fiber that can be received in an optical fiber receiver emits a light beam at an angle to a centerline of the optical fiber, and the respective first surfaces of the lenses associated therewith are the axis of the lens. 26. The fiber optic switching module of claim 25, wherein the fiber optic switching module is oriented at a tilt angle with respect to each other and is configured to be substantially aligned with the axis of the lens within each lens. 49. The focal point of each lens is substantially on its tilt angle surface, and the end of the optical fiber which can be received by the associated optical fiber receiver is positioned within one Rayleigh range from the tilt angle surface. 49. The fiber optic switching module of claim 48 configured to be. 50. The optical fiber that can be received by the optical fiber receiver is a compound optical fiber, and the lenses respectively associated with them are further oriented at an inclination angle with respect to the axis of the lens and have a first surface thereof. There is a second surface that intersects and is not parallel so that two exits / enters in each lens from / to one end of each associated compound lens at different angles to the optical fiber centerline. 49. The fiber optic switching module of claim 48 configured to align with the axis of the lens. 51. The fiber optic switching module of claim 50, wherein the two are configured to propagate in opposite directions through the duplex optical fiber. 52. The fiber optic switching module of claim 50, wherein the two are configured to propagate in one direction through the duplex optical fiber. 53. From a small diameter outer surface located proximal to one end of the optical fiber that can be received in a respective associated fiber optic receiver, and from one end of the optical fiber that can be received in a respective associated fiber optic receiver. 26. The optical fiber of claim 25 configured to have a larger diameter outer surface located further distally formed on the lens.
Switching module.