JP2000249936A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a moving mechanism of a moving side optical fiber of a mechanical optical switch, more particularly to miniaturize the optical switch 20 when the number of cores of the stationary side optical fiber is small. SOLUTION: The optical switch 20 is used to switch and connect, for example, one piece of the moving side optical fiber 4 to the desired stationary side optical fiber 3 by moving the moving side optical fiber in the arraying direction (arrow (a) direction) of a plurality of the stationary side optical fibers 3. The stationary side optical fibers 3 are housed and fixed into the plural positioning grooves 22 on a positioning groove base 21. As the moving mechanism 23 for moving the moving side optical fiber 4, the free ends of two pieces of cantilevered flexible links 25 parallel with each other using lamination type piezoelectric elements are connected to each other by a connecting member 26 and the front end side part of the moving side optical fiber 4 is fixed to the connecting member 26. A drive circuit 27 for applying deflection and deformation to the lamination type piezoelectric elements (flexible links 25) is disposed. When the lamination type piezoelectric elements (flexible links 25) are deflected and deformed, the connecting member 26 moves in parallel and the moving side optical fiber 4 moves in the arraying direction in the state of maintaining the parallel state, by which the moving side optical fiber 4 may be located at the position of the desired stationary side optical fiber 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for positioning a plurality of fixed optical fibers fixed in a line in parallel by moving a movable optical fiber facing the fixed optical fibers in a direction in which the fixed optical fibers are arranged. The present invention relates to a mechanical type optical switch that switches and connects to a fixed-side optical fiber in a groove.

[0002]

2. Description of the Related Art In an optical communication system, an optical line test system for monitoring whether the optical line is functioning properly, and performing maintenance and management is used. A mechanical optical switch can be used. As a mechanical optical switch of this type, ferrule-type optical connectors are attached to the ends of the fixed-side optical fiber and the moving-side optical fiber, respectively, and the switching connection between the moving-side optical fiber and the fixed-side optical fiber is performed by switching the optical connector. There is a method to do it. However, since this method has a complicated structure, a method has been developed in which optical fibers are directly butt-connected to each other in a selected positioning groove. FIG. 7 shows a conventional optical switch of this kind. The optical switch 5 includes a plurality of fixed optical fibers 3 in positioning grooves 2 such as a plurality of V grooves provided in positioning groove base 1.
Is fixed with an adhesive or the like, and the movable optical fiber 4 to be selectively connected to these fixed optical fibers 3 is aligned with the fixed optical fibers 3 in the arrangement direction (the groove arrangement direction of the positioning groove base 1). : Arrow (a) direction in FIG. 7).

Conventionally, as a moving mechanism for moving the moving side optical fiber 4 in the direction in which the fixed side optical fibers 3 are arranged, for example, as shown in the drawing, a moving head 6 to which the moving side optical fiber 4 is fixed with an adhesive or the like is used as a straight line. A linear motion guide 7 such as a guide shaft for guiding
A moving mechanism or the like in which a ball screw 9 that is rotated and driven by a nut is screwed into a nut portion 6a of the moving head 6 is adopted. In this optical switch 5, when connecting the movable optical fiber 4 to the desired fixed optical fiber 3, the ball screw 9 is driven to rotate by the pulse motor 8 to move the movable head 6 along the linear motion guide 7, Moving side optical fiber 4
Is positioned on the desired positioning groove 2. This state is shown in FIG. Next, the distal end of the movable optical fiber 4 is dropped into the positioning groove 2 by, for example, pressing down with a clamp 11 and fitted thereinto.
To connect.

[0004]

In the above conventional optical switch 5, a moving head 6 includes a linear motion guide 7 and a ball screw 9 as a moving mechanism for moving the moving side optical fiber 4 in the direction in which the fixed side optical fibers 3 are arranged. In this case, the moving mechanism occupies a large space, and the apparatus becomes large.
When the fixed optical fiber side has a large number of cores such as 800 cores, the size of the moving mechanism portion does not particularly matter relatively, but in the case of a small number of cores such as 8 cores and 16 cores, The size of the moving mechanism is too large for the necessary moving amount of 1 mm to 2 mm, which is an obstacle to downsizing the entire optical switch.

Further, the present mechanical optical switches including the optical switch 5 do not have a configuration in which a large number of inputs and a large number of outputs can be arbitrarily and quickly switched and connected. Although it cannot be used for such purposes, it is preferable if a switchboard or the like can be constituted by a mechanical optical switch.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional drawbacks. The present invention has been made to reduce the size of the moving mechanism for moving the moving-side optical fiber, and to reduce the size of the optical switch when the fixed-side optical fiber has a small number of fibers. In addition, for a mechanical multi-fiber connection that can be switched arbitrarily and quickly between many inputs and many outputs by combining this miniaturized optical switch. It is an object of the present invention to realize an optical switch.

[0007]

In order to solve the above-mentioned problems, the present invention provides a plurality of fixed optical fibers housed and fixed in a plurality of mutually parallel positioning grooves, and a movable optical fiber opposed to the fixed optical fibers. In a mechanical type optical switch that is moved in the direction in which the optical fibers are arranged and is switched and connected to the fixed-side optical fiber in the selected positioning groove, as a moving mechanism that moves the moving-side optical fiber in the direction in which the fixed-side optical fibers are arranged. Connecting the free ends of two cantilevered flexible links parallel to each other using a laminated piezoelectric element in which bending deformation occurs in the arrangement direction when a voltage is applied to at least one of the flexible links by a connecting member; It is characterized in that a driving circuit for fixing the distal end side portion of the moving side optical fiber to the member and for giving a bending deformation to the laminated piezoelectric element is provided.

According to a second aspect of the present invention, in the optical switch according to the first aspect, a strain gauge is attached to at least one of the flexible links, and the amount of flexure of the flexible link detected based on the amount of strain detected by the strain gauge. Is fed back to the drive circuit to control the position of the moving-side optical fiber.

A third aspect of the present invention is an optical switch constructed by combining a plurality of the optical switches according to the first aspect, wherein each of the optical switches has the configuration of the optical switch according to the first aspect. M first optical switches comprising fixed optical fibers, and n second optical switches comprising one moving optical fiber and m fixed optical fibers are arranged opposite to each other, and The n fixed-side optical fibers of each of the first optical switches are distributed and connected to the fixed-side optical fibers of the n second optical switches, respectively, and m of each of the n second optical switches is m. The fixed optical fibers are distributed and connected to the fixed optical fibers of the m first optical switches.

[0010] Here, the laminated piezoelectric element is, for example, a structure in which a metal elastic plate is used as a central electrode and two thin plates of the piezoelectric element are bonded together, and a bending deformation occurs when a voltage is applied to the electrodes of the piezoelectric element. Which is generally called a piezoelectric bimorph. However, the present invention is not necessarily limited to a two-layer structure including two piezoelectric elements, and includes a three-layer or more piezoelectric element.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a plan view of an optical switch 20 according to one embodiment of the present invention, and FIG. 2 is an AA enlarged cross-sectional view of a main part of FIG. The optical switch 20 of this embodiment is for switching and connecting one moving optical fiber 4 to a plurality of fixed optical fibers 3, and the fixed optical fibers 3 are parallel to each other provided on a positioning groove base 21. The plurality of positioning grooves 22 are housed and fixed with an adhesive or the like such that the tips are located at the centers of the grooves. The positioning groove 22 of the embodiment is a V-shaped groove as shown in FIG. Each of the optical fibers 3 and 4 is a bare fiber having a diameter of 125 μm (or a thin coating thereof may be applied), and the groove pitch of the positioning groove 22 is, for example, 127 μm. In the present invention, the moving side optical fiber 4
Are arranged in the direction in which the fixed-side optical fibers 3 are arranged (the direction of the arrow (a) in FIG. 1). The free end of the cantilevered flexible link 25 is connected by a connecting member 26, and the distal end portion of the movable optical fiber 4 is fixed to the connecting member 26 by, for example, an adhesive or the like. A drive circuit 27 is provided to apply a flexible deformation to the flexible link (that is, the laminated piezoelectric element) 25. Further, a strain gauge 32 for detecting the amount of bending of the flexible link 25 is attached to one surface near the fixed end of one flexible link 25. Although the moving optical fiber 4 is moved to the desired position of the positioning groove 22, the drop fitting means for dropping and fitting the tip of the moving optical fiber 4 into the positioning groove 22 is not shown. For example, a method in which the clamper 11 is provided as in the conventional example, or a method in which the entirety of the flexible link 25 is swung up and down about the fixed end side to lower the distal end side of the movable optical fiber 4. Etc. are optional.

The laminated piezoelectric element (flexible link 25)
Has a structure in which a metal elastic plate 28 is used as a central electrode and two plate-like piezoelectric elements 29 are bonded together, as shown in a detailed cross section in FIG. The piezoelectric element 29 has a configuration in which electrodes (29b, 28 (the metal elastic plate 28 is used as a common electrode)) are attached to both surfaces of a piezoelectric ceramic 29a. And
When a voltage is applied to the electrodes 28 and 29b of each piezoelectric element 29 by a drive circuit 27 connected so that a voltage is applied in reverse polarity as shown in FIG. 1, one piezoelectric element 29 expands and the other piezoelectric element 29 expands. Is shrunk, so that the entire laminated piezoelectric element 24 bends and deforms. In order to cause bending deformation, one must expand and the other needs to contract, so that it basically has a two-layer structure composed of two piezoelectric elements, which is generally called a piezoelectric bimorph. Is not necessarily limited to the two-layer structure as long as it generates the following. In addition, the length of the multilayer piezoelectric element 24 of the embodiment is, for example, about 10 cm.

[0013] As shown in FIG.
A metal resistive material 32a such as a foil or a wire is coated with a film-like base 3 such as a resin.
2b, which is attached to the surface of the object to be measured, and its lead wire 32c is connected to a strain measuring device (not shown) for use.
This is detected as a change in the resistance value a. Note that the amount of bending of the flexible link 25 can be detected by an operation based on the amount of surface distortion of the flexible link 25 in the longitudinal direction.
Then, the bending amount of the flexible link 25 detected based on the strain gauge 32 is fed back to the drive circuit 27 to control the moving amount of the distal end of the flexible link 25, that is, to control the moving-side optical fiber 4. Position control is performed. In the illustrated example, the strain gauge 32 is attached to one surface of the flexible link 25. However, if the strain gauge 32 is attached to both surfaces of the flexible link 25, the difference between the two can be taken to improve the measurement accuracy.

Although FIG. 1 shows the main part of the optical switch 20, in actuality, as shown in FIG. 4, the optical switch 20 is preferably provided in a sealed case 35 filled with an oil-like refractive index matching agent 34. . Thereby, the connection loss between the fixed side optical fiber 3 and the movable side optical fiber 4 in the positioning groove 22 can be reduced.

In the optical switch 20, when a voltage is applied to the laminated piezoelectric element (flexible link 25) from the drive circuit 27, the two flexible links 25 having the same length are similarly bent and deformed. The connecting member 26 at the tip is the fixed side optical fiber 3
Therefore, the distal end portion of the moving side optical fiber 4 moves in the direction in which the fixed side optical fibers 3 are arranged while maintaining the state parallel to the longitudinal direction of the positioning groove 22. In this case, the position control of the movement of the movement-side optical fiber 4 is performed by feeding back a strain detection signal from the strain gauge 32 to the drive circuit 27, thereby controlling the amount of bending of the flexible link 25 and moving the movement. The position of the side optical fiber 4 can be accurately controlled, and the movable side optical fiber 4 can be positioned at a desired position of the positioning groove 22, that is, at the position of the fixed side optical fiber 3 to be connected.

In the above-described embodiment, both of the two flexible links 25 are constituted by laminated piezoelectric elements, but one of the flexible links may be a simple leaf spring. In the above-described embodiment, the number of the movable optical fibers 4 is one, but two or more optical fibers may be provided. That is, two or more moving optical fibers parallel to each other are fixed to a connecting member 26 connecting the flexible links 25 of the moving mechanism 23, and a plurality of moving optical fibers are collectively collected. Switching connection for simultaneous connection to the same number of fixed-side optical fibers as is performed.

The above optical switch 20 is, for example, (m + n)
M × n switching optical switch 4 that can switch and connect m inputs and n outputs in any combination using
0 can be configured. FIG.
Is shown in a schematic plan view, and FIG. 6 schematically shows the same. This optical switch 40 uses m number of 1 × n switchable first optical switches 41 each including one moving-side optical fiber 4 and n fixed-side optical fibers 3.
1G, n second optical switches 42 of 1 × m switching composed of one moving-side optical fiber 4 and m fixed-side optical fibers 3 are used as a second optical switch group 42G. The optical switch groups 41G and 42G face each other as shown, and the fixed-side optical fibers 3 in both optical switch groups 41G and 42G are connected as follows. That is, the n fixed-side optical fibers 3 of each first optical switch 41 of the first optical switch group 41G are connected to the second optical switch group 42G.
Each of the G optical switches 3 is distributed and connected to the fixed optical fibers 3 of the n second optical switches 42. On the other hand, the second optical switch group 42G
The m fixed optical fibers 3 of the n second optical switches 42 are respectively distributed and connected to the fixed optical fibers 3 of the m first optical switches 41 of the first optical switch group 41G. The fixed optical fibers 3 may be connected to each other by fusion splicing.

In the above-mentioned optical switch 40, the m first optical switches 41 and the n second optical switches 42 can be connected in all combinations, and therefore, the m optical switches 41G on the first optical switch group 41G side can be connected. The moving optical fibers 4 are input (I _{1 to} Im in FIG. 6), and the n moving optical fibers 4 on the second optical switch group 42G side are output (O ₁ to O _{m in} FIG. 6).
O _n ), m inputs and n outputs can be connected in any combination. The switching operation of the optical switch 40 is performed by the individual optical switch 20.
The switching operation is performed by a very small distance of, for example, from about 127 μm to about 1 to 2 mm, and the displacement speed when a voltage is applied to the multilayer piezoelectric element is extremely fast. An extremely quick switching operation can be realized. In addition, each optical switch 2
Since 0 is sufficiently small, the density can be easily increased, a large number of optical switches 20 can be mounted, and an arbitrary number of optical fibers can be arbitrarily switched and connected. Therefore, there is a high possibility that it can be used as an exchange in an optical communication network.

The above-mentioned m × n switching optical switch 40 includes a first optical switch group 41G and a second optical switch group 4G.
2G and 2G are manufactured as separate devices.
The fixed optical fibers 3 may be connected to each other by another optical fiber, or the first optical switch group 41G
And the second optical switch group 42G are arranged as one device in the same case, and the fixed optical fiber 3 connecting the two 41G and 42G is replaced by a common fixed optical fiber 3 connecting the two directly. It can also be.

In the above embodiment, the switching is performed by m × n. However, n is set to the same number as m (n = m).
An optical switch of m × m switching using m optical switches 20 may be used. In this case, only one type of optical switch is required, which is advantageous for cost reduction and is often considered appropriate in actual use.

[0021]

According to the optical switch of the first aspect, since the movable optical fiber is supported and moved by the cantilevered flexible link using the laminated piezoelectric element, the movable optical fiber is moved. The size of the moving mechanism can be significantly reduced.Especially, when the fixed optical fiber side has a small number of optical fibers, the optical switch can be easily reduced in size and the structure is simple, so that the optical switch can be manufactured at low cost. Can be manufactured.

According to the second aspect, the amount of flexure of the flexible link is detected by the strain gauge attached to the flexible link, and feedback is provided to a drive circuit that flexibly drives the flexible link (laminated piezoelectric element). Then, since the position of the moving-side optical fiber is controlled, accurate position control of the moving-side optical fiber can be performed.

According to the third aspect, by combining the miniaturized optical switches described above, a mechanical light for multi-core connection can be arbitrarily and quickly switched and connected between a large number of inputs and a large number of outputs. A switch can be realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of an optical switch according to an embodiment of the present invention.

FIG. 2A is an enlarged sectional view taken along the line AA in FIG. 1;
(B) is a sectional view taken along the line CC.

FIG. 3 is a diagram illustrating a strain gauge in FIG. 1;

FIG. 4 is a plan view schematically illustrating the entire configuration of the optical switch of FIG. 1;

FIG. 5 is a schematic plan view of an optical switch according to a third embodiment.

FIG. 6 is a plan view schematically illustrating the configuration of the optical switch of FIG. 5;

FIG. 7 is a plan view of a conventional optical switch.

FIG. 8 is an enlarged BB cross-sectional view of the optical switch of FIG. 7;

[Explanation of symbols]

 Reference Signs List 3 fixed optical fiber 4 movable optical fiber 20 optical switch 21 positioning groove base 22 positioning groove 23 moving mechanism 25 flexible link (laminated piezoelectric element) 26 connecting member 27 drive circuit 28 metal elastic plate 29 piezoelectric element 29a piezoelectric ceramic 29b Electrode 32 Strain gauge 32a Metallic resistance material 32b Film base 32c Lead 34 Refractive index matching agent 35 Case 40 Optical switch 41 First optical switch 42 Second optical switch 41G First optical switch group 42G Second optical switch group

Claims (3)

[Claims] 1. A plurality of fixed optical fibers housed and fixed in a plurality of positioning grooves parallel to each other, and a moving optical fiber opposed to the plurality of fixed optical fibers is moved in a direction in which the fixed optical fibers are arranged. In a mechanical type optical switch that switches and connects to a fixed-side optical fiber in a groove, as a moving mechanism that moves the moving-side optical fiber in a direction in which the fixed-side optical fibers are arranged, at least one of the optical fibers bends in the direction in which the voltage is applied when the voltage is applied. The free ends of two cantilevered flexible links parallel to each other using a laminated piezoelectric element are generated by a connecting member, and the distal end portion of the movable optical fiber is fixed to the connecting member. And an optical switch provided with a drive circuit for applying a bending deformation to the laminated piezoelectric element. 2. A strain gauge is attached to at least one of the flexible links, and the amount of flexure of the flexible link detected based on the amount of strain detected by the strain gauge is fed back to the drive circuit, and 2. The optical switch according to claim 1, wherein the position of the optical fiber is controlled. 3. The optical switch according to claim 1, wherein m first optical switches each comprising one moving-side optical fiber and n fixed-side optical fibers, and one moving switch. N second optical switches each including a side optical fiber and m fixed side optical fibers are arranged to face each other, and the n fixed side optical fibers of each of the m first optical switches are each replaced with the n fixed side optical fibers. The fixed side optical fibers of the second optical switch are respectively distributed and connected, and m fixed side optical fibers of each of the n second optical switches are respectively connected to the fixed side optical fibers of the m first optical switches. An optical switch characterized by being distributed and connected.