JPH02162311A - Optical fiber switch array - Google Patents

Abstract

PURPOSE:To obtain the high-reliability optical fiber switch array with low insertion loss by arranging lens systems which function to increase the diameters of light beams emitted from optical fibers at every optical fiber on the opposite end surface sides of the optical fibers corresponding to the respective optical fibers. CONSTITUTION:When connections are switched by respective optical fiber switches so as to form optical paths of optical fibers 11A-1 and 11B-2, 11B-4 and 11A-3, 11A-5 and 11B-6, and 11B-8 and 11A-7 a stopper 161 is moved up by a movement quantity control part 16 to separated from a long groove formed of grooves 124-1 and 133 for positioning, thereby allowing a movable optical fiber array 12 to move as shown by an arrow A. The movement quantity control part 16 moves down the stopper 161 to insert the stopper into the long groove formed of grooves 124-2 and 133 for positioning. At this time, both fibers 11A and 11B can be matched with the matching parts of the optical fibers 11A and 11B through lens systems 17A and 17B which increases the spot diameters of the light beams with position accuracy of <=2mum.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an optical fiber switch array used in the fields of optical communication and optical information processing, and in particular, the present invention relates to an optical fiber switch array used in the fields of optical communication and optical information processing, and in particular, the present invention relates to an optical fiber switch array used in the fields of optical communication and optical information processing. It can be done in combination (
This invention relates to an optical fiber switch array in which optical fiber switches (lxN) are arranged into an array.

(Prior art) Fig. 2 is a diagram schematically showing the configuration of a conventional (IXN) optical fiber switch, in which (a) is a top view of the cylinder, and (b) is a simplified cross-section. (H, Yamamoto
and 11.0g1vara, ”Moving
optical-flcrswitch experi
ment”, Appl, opt, Vol 17.p
p 3675-3678. (1978)).

In FIG. 2, 1 is a movable optical fiber, 2 is a movable pipe holding the movable optical fiber, 3-1 to 3N are fixed optical fibers, 4-1 to 4-N are V grooves for positioning the movable pipe 2, and 5 -1 to 5-N are connection V grooves into which one end of the movable optical fiber 1 is inserted or removed, and 6-1 to 6-N are connections in which one ends of the fixed optical fibers 31 to B-N are buried respectively. It is a V-groove for use.

Next, in such a configuration, for example, a connection switching operation for forming an optical path between the movable optical fiber 1 and the fixed optical fiber 3-2 will be explained with reference to FIG.

First, as shown in FIG. 2(a), the movable pipe 2 is rotated in the direction of the arrow a using one end of the movable pipe 2 as a fulcrum, and a positioning groove corresponding to the fixed optical fiber 32 to be connected is formed. 4-2 and connecting V-groove 5-2 are selected. Next, as shown in FIG. 2(b), the movable pipe 2 is pressed in the direction indicated by the arrow in the figure (downward in the figure), and the fixed optical fiber is pushed in the direction indicated by the arrow C in the figure, that is, the fixed optical fiber 32 and abut the end surfaces of the movable optical fiber 1 and the fixed optical fiber 3-2 to switch the connection.

In fact, the above-mentioned configuration (I
X9) In the prototype optical fiber switch, the connection loss was 0.3.
d13 has been obtained.

(Problem to be Solved by the Invention) However, according to the above-mentioned optical fiber switch, when switching connections, the movement of the movable optical fiber 1 consists of rotational movement for positioning, and This is a complicated motion consisting of vertical movement of the optical fiber and sliding movement to bring the end faces of the optical fibers together.This is necessary to achieve splice loss of 1d13 or less due to deflection caused by the elasticity of the optical fiber. It is almost impossible to achieve position accuracy of 1 μm or less with good reproducibility. Therefore, there is no problem when using a multimode optical fiber with a large core diameter of several tens of μm, but a single mode with a core diameter of 10 μm or less requires strict alignment adjustment accuracy when abutting the optical fiber end faces. There was a problem in that it was not possible to use optical fibers.

In addition, with the above configuration, it is difficult to manufacture an array of (IXN) optical fiber switches in an integrated structure, and furthermore, since the rotational movement of the optical fiber is used, it is difficult to miniaturize the switch. There was a problem with this.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an optical fiber switch array that can switch connections with a simple operation, greatly reduce positional accuracy when moving optical fibers, and further reduce the size. be.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a plurality of optical fibers arranged in parallel at predetermined intervals in a two-dimensional manner,
Two optical fiber arrays are arranged such that one end of each optical fiber faces each other, and one of these optical fiber arrays is parallel to the plane where the optical fibers are arranged parallel to each other, and a moving mechanism section that moves the optical fiber array in a direction perpendicular to the fiber axis; and a moving amount regulating section that regulates the moving amount of the one optical fiber array according to the spacing between the optical fibers, the opposing end surfaces of each of the optical fibers; On the side, a lens system having a function of enlarging the diameter of the light beam emitted from each optical fiber was arranged for each optical fiber.

(Function) According to the present invention, for example, -
The light that has propagated through the optical fiber is emitted from one end surface of the optical fiber, and the emitted light passes through a lens system to expand its light beam diameter. Next, this expanded light beam is focused by opposing lens systems, enters one end face of the opposing optical fiber of the other optical fiber array, and is propagated.

Next, to switch the connection of the optical path in order to propagate the light propagating through the - optical fiber of one optical fiber array to the other optical fiber of the other optical fiber array, first,
Release the movement amount restriction of one optical fiber array by the movement amount restriction section. Next, one of the optical fiber arrays is moved by a desired distance according to the spacing between the optical fibers by the moving mechanism. Next, the movement amount regulating section restricts the movement amount of one optical fiber array, thereby completing the connection switching.

(Embodiment) FIG. 1 is a perspective view showing an embodiment of an optical fiber switch array according to the present invention. In FIG. 1, 10 is a substrate, 11A, 1], and B are predetermined intervals, for example, 150 μm to
Eight single-mode optical fibers (hereinafter referred to as optical fibers) are arranged in parallel two-dimensionally with a desired value within a range of 1 mm at equal intervals. 12 is a movable fiber that can be moved in the direction of arrow A in the figure. an optical fiber array; 13 is a fixed optical fiber array;
Reference numeral 14 indicates a guide section for the movable optical fiber array 12 extending in the direction of arrow A in the figure, 15 indicates a moving mechanism section for the movable optical fiber array 12, and 16 indicates the amount of movement of the movable optical fiber array 12 in parallel with the optical fiber IIA. This is a movement amount regulating section that regulates according to the set interval.

FIG. 3 is an explanatory diagram of movable and fixed optical fiber arrays,
(a) of the same figure is a partially omitted cutaway perspective view, and (b) of the same figure is a simplified sectional view. The movable optical fiber array 12 includes a base 121 whose lower surface side convex portion is fitted into the guide portion 14 fixed on the substrate 10, and optical fiber fixing grooves (in this embodiment, optical fiber fixing grooves formed at predetermined intervals on the upper surface of the base 121). 8 pieces) 12
An optical fiber IIA whose one end is buried in 1a and a lens fixing groove 121b connected to the tip of each optical fiber fixing groove 121a and having a function of enlarging the spot diameter of the light beam, for example, a sphere. A lens system 17A consisting of lenses, etc., and these lens systems 17A and an optical fiber IIA
It consists of a fiber lens fixing jig 122 for fixing the fiber lens, and a protrusion 123 (FIG. 1) connected to the actuator 151 of the moving mechanism section 15. On the upper surface of the base 121, a stopper 161 of the movement amount regulating section 16, which will be described later, is provided.
three positioning grooves 124- into which the
1, 124-2, 124-3 are formed at predetermined intervals.

The fixing optical fiber array 13 includes a base 131 fixed on the substrate 10, and an optical fiber fixing groove 131a formed on the upper surface of the base 131 at a predetermined interval (same as the interval for fixing optical fibers?+M121a). For fixing the optical fiber IIB with its one end fixed, the lens system 17B fixed in the lens fixing groove 131b connected to the tip of each optical fiber fixing groove 131a, and the lens system 17B and the optical fiber IIB. It consists of a fiber lens fixing jig 132. On the top of Beth 131,
One positioning groove 133 is formed into which a stopper 61, which will be described later, is inserted or removed.

The movable optical fiber array 12 and the fixed optical fiber array 13 are arranged so that the end surfaces of the lens systems 17A and 17B are butted against each other. Regarding alignment of the optical fibers, when the movable optical fiber array 12 is not movable and is in the initial state as shown in FIG. 1, the optical fibers IA1 and IIB-1, IIA-2 and IIB-2
, . . , matching is performed so that an optical path is formed between 11A-8 and IIB-8.

The moving mechanism section 15 is composed of, for example, a solenoid type actuator, and the actuator 151 is connected to the protruding section 123 of the movable optical fiber array 12 as described above. The movable optical fiber array 12 moves a desired distance ( In this embodiment, the optical fibers are moved by a distance equal to the distance between the parallel optical fibers and twice that distance.

FIG. 4 is an explanatory diagram of the movement amount regulating section 16, and (a) of the figure
is a perspective view showing a state in which the amount of movement of the movable optical fiber array 12 is not regulated, and (b) of the figure is a perspective view showing a state in which the amount of movement of the movable optical fiber array 12 is regulated. The movement amount regulating section 16 is a base 13 of the fixed optical fiber array 13.
The actuator includes a solenoid type actuator that is provided on the top surface of the device and moves in a direction perpendicular to the top surface, that is, in a vertical direction.

The stop 161 consisting of this actuator has an oval shape, and the lower surface of its longitudinal part is formed by the positioning groove 124.
-1 or 124-2 or 124-3 and the positioning groove 133 to facilitate insertion into the long groove.

Next, based on FIG. 5, the array configuration of the optical fiber switch array shown in FIG. 1 will be explained.

In addition, in Fig. 5, ◎ indicates the input side, O indicates the output side, and II
A-1 to IIA-8 and 11B-1 to 11B-8 are optical fibers.

As can be seen from FIG. 5, the optical fiber switch array of FIG. 1 has a configuration in which four (IX3) optical fiber switches are integrated. That is, the optical fiber main board IIA-
1 and optical fiber IIB-1゜2.3, optical fiber IIB
-4 and optical fiber 11A-4, 3, 2, optical fiber II
A-5 and optical fiber IIB-5, 6, 7, optical fiber I
It has a 4-array configuration in which four (IX3) optical fiber switches constituted by IB-8 and optical fibers IIA-8, 7, and 6 are integrated.

Next, from the state shown in FIG. 1, in each optical fiber switch, optical fiber IIA-1 and optical fiber 11B-2, optical fiber IIB-4 and optical fiber 11A-3, optical fiber 1], A-5 and optical A connection switching operation for forming an optical path with the fiber 11B-6, the optical fiber 11B-8, and the optical fiber 11A-7 will be described.

First, the stopper 161 is moved upward by the movement amount regulating section 16 to separate from the long groove formed by the positioning grooves 124-1 and 133, and the movable optical fiber array 12
is made movable in the direction of arrow A in FIG. Next, the actuator 151 is caused to protrude by a stroke corresponding to the spacing between the optical fibers by the moving mechanism section 15. As a result, the protrusion 12 of the movable optical fiber array 12
3 is pushed (toward the near side in FIG. 1), the base 121 of the movable optical fiber array 12 is guided by the guide portion 14, and is at the position shown in FIG. 4(a), that is, the positioning groove 124-
2 is located approximately below the stopper] 61, and moves to a position where a long groove is formed by the positioning groove 124-2 and the positioning groove 133.

Next, the stopper 161 is moved downward by the movement amount regulating section 16 and inserted into the long groove.

At this time, since the lower surface side of the stopper 161 is V-shaped, it is inserted smoothly, thereby restricting the amount of movement of the movable optical fiber array 12 (see (b) in FIG. 4).
state), the connection switching of the optical path is completed.

By the way, in the mechanical connection switching as described above, 2μ
Optical fiber 11A with position accuracy of less than m.

It is very difficult to move 11B with good reproducibility.

Furthermore, the normally required (-)20°C to (+)60°C
The base 121 and base 131 on which the optical fibers IIA and 11B are mounted and the substrate 10 that supports them are deformed due to thermal expansion due to temperature changes. It is also difficult to maintain the position accuracy below. However, as mentioned above, since the lens systems 17A and 17B, which are made of spherical lenses and have the function of enlarging the spot diameter of the light beam, are arranged at the matching parts of the optical fibers IIA and IIB, their positional accuracy (axis (misalignment) is significantly alleviated, and low-loss optical transmission is performed.

Next, the lens systems 17A and 17B will be explained in more detail.

Figure 6 is a graph showing the relationship between the axis misalignment between optical beams and the resulting excess loss, using the spot diameter 2ω at the optical fiber connection end as a parameter, where the horizontal axis is the axis misalignment and the vertical axis is the excess loss. The wavelength is 1.3 μm, the axial distance between opposing optical fibers is 10 μm, and the optical fiber end face is coated with an anti-reflection coating.

As is clear from FIG. 6, when the spot diameter 2ω is increased, the axis misalignment tolerance is significantly relaxed. for example,
When using a single mode optical fiber with a spot diameter 2ω of 10 μm under the condition that the allowable value of excess loss is 0.5 dB,
The axis misalignment tolerance is 1.6 μm, but by setting the spot diameter 2ω to 20 μm, the axis misalignment is 3.3 μm.
Further, by setting the spot diameter 2ω to 30 μm, the axis deviation is allowed to be up to 5 μm.

Therefore, by arranging a lens system for each optical fiber that has the function of enlarging the spot diameter of the light beam on the light input/output end face of the optical fiber, the movement position accuracy caused by the mechanical connection switching operation described above can be greatly alleviated. become.

FIG. 7 and FIG. 8 are diagrams showing an example of the configuration of a lens system having the above-described functions.

FIG. 7(a) shows ball lenses 17A-a and 17 made of glass or sapphire as lens systems 17A and 17B.
An example using B-a, (b) in the same figure is a glass (m +
1/4) pitch rod lens 17A-b, 17113
An example using a normal GRIN rod lens manufactured by external diffusion of -b, e.g. Tj) or a rod lens made of a multimode graded index optical fiber (here, m = 0.1.2...), (e) of the same figure shows glass Fresnel convex lenses 17A'-c and 17B-c.
An example using each is shown.

In these lens systems, (a) and (b) in Fig. 7
In the case of
-c, 17B-c, and the optical fiber I
The light emitted from the end faces of IA and IIB is transmitted through these ball lenses 1.
7A-a, 17Ba and Fresnel convex lens 17A-c,
After passing through 17BC, it is configured to become a parallel beam.

In addition, in the lens system of FIG. 7(b), the end surfaces of optical fibers IIA and IIB are connected to rod lenses 17Ab and 17B.
-b, respectively, or arranged with a slight gap between them.

In the case of FIG. 7(a), the ball lens 17A-a.

Letting the radius of 17B-a be γ, it is determined by f=γ 2 (n-1). Here, assuming that the spot diameter of the light beam at the end faces of the optical fibers IIA and IIB is 2ω0, the spot diameter 2ω of the light beam immediately after passing through the spherical lenses 17A-a and 17B-a is determined by the following equation.

Actually, in the configurations shown in FIGS. 1 and 3, the lens system 1
As a result of using spherical lenses with a diameter of 100 μm as 7A and 17B, the spot diameter of the light beam at the end face of the optical fibers IIA and IIB is expanded from 10 μm to 27 μm, and the transmission loss is 0.
The movement position accuracy of the optical fibers increased by 5 dB, that is, the movement position accuracy of the movable optical fiber array 12 was significantly improved from about 1.8 μm to 4.6 μm.

In addition, as the lens systems 17A and 17B, the focusing parameter g
As a result of using a rod lens cut into a 5/4 pitch multimode optical fiber with a diameter of 5.8+nn+-', the spot diameter of the light beam at the end faces of optical fibers IIA and IIB is 10μ.
m was expanded to 27 μm, and the moving position accuracy of the optical fiber with an increase of 0.5 dB in excess loss, that is, the moving position accuracy of the movable optical fiber array 12 was significantly improved from about 1.6 μm to 3.6 μm.

Furthermore, the lens systems 17A and 17B have a focal length of 15
As a result of using a 0 μm Fresnel convex lens, the spot diameter of the light beam at the end faces of the optical fibers 11A and IIB could be expanded from 10 μm to 27 μm, as in the case of using a spherical lens.

In addition, FIG. 8 shows that the wavelength range used is, for example, 1.3 μm-
An example is shown in which an achromatic lens system with improved chromatic aberration is configured to be applied to a wide range such as 1.6 μm.

In FIG. 8(a), the spherical lenses 17A-a, 17Ba and concave lenses 18A-'a, 18B-a are combined, so the focal length of the spherical lenses 17A-a, 17B-a is f 1
Let Atsbe's number be ν1, and the focal length of concave lens 1■ 8A-a and 18B-a be f 1 Atsbe's number be ν
Chromatic aberration is improved by determining the lens material and lens shape so as to satisfy the relationship f < f , ν × ν2. As the lens material, ball lens 17A-a,
17B-a has a crown glass, concave lens 18A-a
, 18B-a uses flint glass. As is well known, the focal length F of such a combination lens is expressed by the following formula: 1/F = l/f + l/L.

■ is required.

Moreover, (b) of FIG. 8 shows the rod lenses 17Ab, 17
B-b is combined with concave lenses 18A-b and 1.8Bb. Here, concave lenses 18A-b, 18B-b
The Atsube number is higher for rod lenses 17A-b and 17B-b.
is selected so that it is larger than the Atsbe number. Also, depending on the focal length of the concave lenses 18A-b and 18B-b, the rod lenses 17A-b and 17B-b are (m + 1/4)
It is slightly longer than the pitch.

FIG. 8C shows a Fresnel convex lens 17A-c.

17B-c and Fresnel concave lenses 19A-c, 19B-c
The focal length and Atsube number of each are selected in the same way as in the case of (a) of the same figure described above.

As described above, according to this embodiment, the movable optical fiber array 12 is moved only in one direction by the moving mechanism section 15, that is,
Optical path connections can be switched by moving only in the direction parallel to the parallel plane of the optical fibers IIAO and perpendicular to the optical fiber axis, and moreover, the end faces of the optical fibers 11A and 1.1B facing each other can be switched. , each optical fiber 11A.

Lens systems 17A and 17B, which have the function of enlarging the spot diameter of the light beam emitted from the end face of optical fiber 11B, are arranged for each optical fiber, thereby greatly reducing the accuracy of the movement position of movable optical fiber array 12 when switching connections. This enables the realization of a highly reliable optical fiber switch array with low insertion loss.

Further, since the optical fibers IIA and IIB fixed to the movable and fixed optical fiber arrays 12 and 13 can be closely arranged at regular intervals to integrate a plurality of optical fiber switches, it is possible to achieve miniaturization.

In this embodiment, the configuration is such that four (IX3) optical fiber switches are integrated, but the present invention is not limited to this. For example, to configure an M array of (IXN) fiber optic switches, if M is an even number, ((1+
N) (1+M) /21 optical fiber array,
Also, if M is an odd number, ((1+N)(1+M)/2
-1] All you need to do is prepare an optical fiber array.

In addition, in order to improve temperature stability, the bases 121, 131 of the component parts of the movable and fixed optical fiber arrays 12, 13, the fiber lens fixing jigs 122, 132, etc. are made of quartz glass or amber, which has a small coefficient of thermal expansion. It is desirable to use the following.

Furthermore, in this example, the single mode destination fiber switch array is configured using a single mode optical fiber as the optical fiber, but the present invention is not limited to this. Of course, a system optical fiber switch array can also be constructed.

(Effects of the Invention) As explained above, according to the present invention, one optical fiber array can be moved in one direction only, that is, parallel to the parallel plane of the optical fibers and along the optical fiber axis. Optical path connections can be switched by moving only in the vertical direction.Moreover, on the end faces of the optical fibers of each optical fiber array facing each other, the diameter of the light beam emitted from the end face of each optical fiber is enlarged. Since a functional lens system is placed for each optical fiber, the movement position accuracy of one optical fiber array when switching connections can be greatly reduced, resulting in a highly reliable optical fiber switch array with low insertion loss. can be realized.

In addition, since one optical fiber array can be moved in one direction and the optical fibers fixed to each optical fiber array can be arranged densely at predetermined intervals, it is possible to
) Fiber optic switch arrays can be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an optical fiber switch array according to the present invention, FIG. 2 is a simplified configuration diagram of a conventional optical fiber switch, and FIG. 3 is an explanation of movable and fixed optical fiber arrays according to the present invention. 4 is an explanatory diagram of the movement amount regulating section according to the present invention, FIG. 5 is an explanatory diagram of the array configuration of the optical fiber switch array of FIG. 1, and FIG. 6 is an explanatory diagram of the optical beam spot diameter and axis deviation Graphs showing the relationship of excess loss, and FIGS. 7 and 8 are diagrams showing an example of the configuration of a lens system according to the present invention. In the figure, 10... substrate, IIA, IIB... single mode optical fiber, 12... movable optical fiber array, 13...
... Fixed optical fiber array, 121, 131 ... Beth, 122, 132 ... Fiber lens fixing jig, 12
3... Projection, 124-1, 124-2, 124-3
．． 133... Positioning groove, 14... Guide portion, 15
...Movement mechanism section, 151...Actuator, 16
...Movement regulating section, 161...Stopper, 17A. 17B...Lens system. Patent Applicant Nippon Telegraph and Telephone Corporation Agent Patent Attorney Yoshi 1) Seiko L h4) Figure 8

Claims (1)

[Scope of Claims] Two optical fiber arrays, each consisting of a plurality of optical fibers arranged two-dimensionally side by side at a predetermined interval, and arranged so that one end surface of each optical fiber faces each other; A moving mechanism unit that moves one of these optical fiber arrays in a direction parallel to the parallel plane of the optical fibers and perpendicular to the optical fiber axis; a movement amount regulating section that regulates the amount of movement according to the spacing between the optical fibers, and a lens system that has a function of enlarging the diameter of the light beam emitted from each optical fiber on the opposite end surface side of each optical fiber. An optical fiber switch array characterized by being arranged in.