JP2002236262A - Optical switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the irradiation situation of a light beam changed during line connection cannot be confirmed by a conventional optical switch. SOLUTION: Four light receiving elements 30 are provided in the outer peripheral part of a mirror 14 for changing an optical path in a desired direction in response to a light beam, and each light intensity incident on these four light receiving elements is measured. Thereby, the center of the optical axis of a beam made incident on the mirror 14 is detected, and the posture of the mirror of a preceding stage which performs irradiation towards the mirror 14 is controlled so that the center of the optical axis coincides with the center of the mirror.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switch for switching an optical signal between a plurality of optical fibers by changing an optical path.

[0002]

2. Description of the Related Art FIG. 21 shows the configuration of an "optical connection module" disclosed in Japanese Patent Laid-Open No. 5-107485. 113 is an optical fiber attached to the array substrate A, 114 is an end of each optical fiber 113, that is, a micro lens located on the array substrate A, and 118 is an opening 116 provided on the array substrate A. The rotating reflection mirrors are positioned so that the reflection angles can be changed in two axial directions.

The array substrate B is also structurally the same as the array A. The two array substrates A and B are fixed so as to face each other at a fixed distance, and emerge from the microlenses of one of the array substrates. The beam is incident on a rotating reflection mirror on the other array substrate.

As can be seen from the optical path 5 shown in FIG. 21, by controlling the rotation angle of the rotary reflecting mirror 118, an optional optical fiber on one array substrate is connected to an optional optical fiber on the other array substrate. Alternatively, an optional optical fiber on one array substrate side can be connected to another optional optical fiber on the same array substrate side.

[0005]

This configuration is a method of calculating the rotation angle of a rotary reflecting mirror in order to change the optical path of a beam at a desired angle. It cannot be detected directly. For this reason, even in the case where the attitude control of the optical path switching element needs to be corrected due to disturbance or the like, such correction cannot be performed.

The present invention provides an optical switch that can directly detect the state of light even during actual line connection.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an optical switch for optionally connecting at least one incident-side optical fiber and at least one output-side fiber, the optical switch being connected to the incident-side optical fiber. An incident port for converting the incident light into a parallel beam by a lens, an exit port for condensing the parallel beam by a lens and guiding it to an exit fiber, and an optional entrance port by changing the optical path of the parallel beam. And a light-receiving element for detecting the amount of received light at the light-path switching element or the condenser lens at the output port portion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows a configuration diagram of an optical switch according to an embodiment of the present invention. Reference numeral 1 denotes an incident port array having a large number of incident ports 11 arranged in an array. Each incident port 11 is connected to an incident fiber 21. Reference numeral 2 denotes an output port array having a large number of output ports 12 arranged in an array. Each output port 12 is connected to an output fiber 22.

Reference numeral 3 denotes an incident-side mirror array, which includes a number of incident-side mirrors 13 in an array. Reference numeral 4 denotes an emission-side mirror array, which includes a large number of emission-side mirrors 14 in an array. The entrance side mirror 13 and the exit side mirror 14 correspond to the above-described optical path switching element and the second optical path switching element.

The outgoing port array 2 is located at the upper right of the incident port array 1 in the drawing, and the incoming mirror array 3 is located at the right of the incoming port array 1 so as to face the outgoing mirror. Array 4 is the output port array 2
Is located on the left side of. As shown in FIG.
If an optical path 23 through which the beam from the incident side fiber 21 enters the exit port array 1 via the entrance side mirror array 3 and the exit side mirror array 4 is ensured, these 4
The arrangement in the two arrays 1, 2, 3 and 4 is not limited to FIG.

FIG. 2 shows the details of the incident port array 1 and the incident side mirror array 3, and the same elements are denoted by the same reference numerals. In FIG. 2, the incident port array 1 is shown in order to show the collimating lens 73 described below.
The angle of one's own is shown. In the entrance port array 1, each entrance port 11 is located as an array 11A, and each entrance port 11 has a collimating lens 7
3 is provided, and converts light from the incident side fiber 21 into a parallel light beam.

In the incident side mirror array 3, each of the incident side mirrors 13 is also positioned as an array 13A, and the optical axis 76 of the beam from each of the collimating lenses 73 so that the beam enters each of the incident side mirrors 13. The entrance side mirror 13 is located on the extension of the above. The configuration relationship between the output port array 2 and the output-side mirror array 4 in FIG.

The entrance-side mirror array 3 and the exit-side mirror array 4 are formed by, for example, a process such as film formation and etching on a silicon substrate, that is, a so-called micromachining technique. It is possible to change the posture to an arbitrary posture with respect to each array substrate surface. These mirrors 1
Reference numerals 3 and 14 are formed by, for example, forming a metal film. Then, as shown in FIG. 3, for example, mirrors 13 and 14 are attached to the substrates of arrays 3 and 4 by a double gimbal mechanism 27.
a, 27b, and the gimbal mechanism 27
If the rotation shafts 28a and 28b of the a and 27b are orthogonal to each other, the mirrors 13 and 14 can be controlled to an arbitrary posture.

As shown in FIG. 4, the incident side mirror array 3
, Each incident port 11 from the incident port array 1
Beam 23 changes the optical path by controlling the attitude of the incident side mirror 13 facing each port,
As shown in FIG. 5, the light is made incident on the output side mirror 14 corresponding to the output side fiber 22 of the connection destination, and the output side mirror 1
In step 4, the optical path 23 is controlled so that the incident beam enters the output port 12 of the output port array 2.

As described above, by controlling the positions of the incident side mirror 13 on the incident side mirror array 3 and the exit side mirror 14 on the exit side mirror array 4, an arbitrary incident port 11 in the incident port array 1 can be controlled. The incident beam is transmitted through the incident side mirror 13 and the exit side mirror 14,
Light can enter any output port 12 in the output port array 2.

For example, when connecting the incoming line connected to the i-th input port Pai and the outgoing line connected to the j-th outgoing port Pbj, the i-th line placed opposite to the Pai If the incident side mirror is Mai and the jth outgoing side mirror arranged opposite Pbj is Mbj, Mai's posture is such that the optical axis center of the reflected light from Pai is the mirror center of Mbj. Is controlled, and the attitude of Mbj is controlled so that the center of the optical axis of the reflected light from Mai becomes the center of the port of Pbj.

FIG. 6 shows the intensity distribution of the beam in the radial direction at the time of spatial propagation, and shows the relative intensity with the intensity at the center of the beam as 1. As can be seen from this intensity distribution, the intensity is strongest at the center of the beam and weaker at the periphery. In the present invention, the center of the optical axis of the beam is detected using the characteristics of the intensity distribution.

As shown in FIG. 7, four light-receiving elements 30 having a 90 ° angle and having a wavelength of incident light as a light-receiving sensitivity region are formed on the periphery of the exit-side mirror 14 so that a part of the incident light is applied. The amount of light that strikes each light receiving element 30 differs depending on the center position of the beam entering from the incident side mirror 13. Further, the emission side mirror 14 is provided near the emission port 12.
Similarly, if the light receiving elements are formed so that a part of the light from the light receiving element strikes, the amount of light applied to each light receiving element differs depending on the position of the center of the optical axis.

For example, a photodiode is used as the light receiving element 30, and a photocurrent generated by the light received by the photodiode is detected, or a resistance change due to the received light is detected by using a photoconductive effect of a semiconductor. Can be known. For example, 1.3 [u
For the [m] band and 1.5 [um] band, configurations such as a Ge photodiode and an InGaAs photodiode, and for the 0.8 [um] band, a Si photodiode can be considered. Can be formed.

In a mirror in which the light receiving element 30 is integrally formed, as shown in FIG.
Are shifted, the respective light receiving elements 3
1, 32, 33 and 34, the amount of incident light PDx1, PD
x2, PDy1, and PDy2 are different from each other as shown in FIG. On the other hand, when the center of the optical axis coincides with the center of the mirror as shown in FIG. 10, there is no difference in the amount of light incident on each light receiving element as shown in FIG. That is,
The optical axis can be made to coincide with the mirror center by controlling the optical axis center position so that the detection amounts of the respective light receiving elements become equal.

A case is considered in which the attitude control of the incident side mirror 13 is performed independently by rotating axes 61 and 62 orthogonal to each other as shown in FIG. When the incident side mirror 13 is rotated about the rotation axis 61 in the situation shown in FIG. 1 as shown in FIG.
In 4, it is assumed that the optical axis center of the beam has moved along the line 64 '. In this case, the incident side mirror 13 is rotated about the rotation axis 62 such that the center of the optical axis moves on a line 64 passing through the center of the exit side mirror 14. Doing the same, line 6 orthogonal to line 64
3 is determined. Alternatively, a line that passes through the center of the emission side mirror 14 and is orthogonal to the line 64 may be determined.

Next, the output side mirror 14 is set on the output side mirror array 4 so that the above-mentioned light receiving elements 31 to 34 are located on both lines 63 and 64. As described above with reference to FIGS. 8 to 11, by switching the light receiving element on the path around the optical axis that is moved by each rotation axis, the light receiving element is switched by the incident side mirror 13 of the incident side mirror array 3. The center of the optical axis of the emitted beam can be accurately matched with the mirror center of the desired output side mirror 14 in the output side mirror array 4.

Similarly, a collimating lens provided at the output port 12 for irradiating the center of the optical axis of the beam switched by the output mirror 14 to the center of the corresponding output port 12 on the output port array 2. The light receiving element described above is also provided for.

As described above, by using a part of the signal light of the line to be switched and using the information of the amount of light received by the light receiving element for the attitude control of the incident side mirror or the exit side mirror, the discrepancy between the optical axis and the mirror center is obtained. , It is possible to reduce the loss of the switch, and to realize an optical switch with low loss. In addition, since the change in the connection state of the line can always be known even during the line connection, there is an effect that a change in loss is small even with external vibrations and the like, and a switch having high resistance to line disconnection can be realized.

Although the first embodiment shown in FIG. 1 has a plurality of incident side fibers 21 and a plurality of exit side fibers 22, an optical switch having the same effect can be constituted with one or two fibers.

Second Embodiment In the first embodiment, a mirror is used as an optical path switching element. However, the optical path switching element is not limited to a mirror, but may be a configuration using a lens, a variable refractive index element, or the like, as shown in FIG. As described above, the incident side mirror array 5 and the exit side mirror array 6
In addition, by switching the connection line by transmission of the lenses 15 and 16 instead of reflection by the mirror, and by integrally forming these lenses and the light receiving element, the same effect as in the previous embodiment can be obtained. In this case, the incident side fiber 2
Since the beam from 1 proceeds toward the output side fiber 22, the input port array 1, the input side mirror array 5, the output side mirror array 6, and the output port array 2 are not three-dimensionally configured as shown in FIG. , Can be arranged in a line.

Third Embodiment In the first embodiment, the light receiving element is provided on the outer periphery of the mirror. However, as shown in FIGS. 15 and 16, a translucent reflecting mirror 41 is provided on the light receiving portion 30 on the substrate 42. The same effect can be obtained by providing a part of the light incident on the reflection mirror 41 to the light receiving part 30. In this configuration, there is an effect that the reflection mirror 41 does not affect the beam shape on the emission side.

Fourth Embodiment In the first embodiment, a total of four light receiving elements are arranged in two pairs in correspondence with the driving axis of the incident side mirror. However, as shown in FIG. May be individual,
Naturally, the number may be five or more. In any case, the optical axis center position can be calculated based on the detection amount of the light receiving element, and the optical axis center can be made to coincide with the mirror center.

Fifth Embodiment In the first embodiment, the light receiving element is used in which the wavelength of the signal light of the line to be switched is set to the light receiving sensitivity range. As shown in FIG. 18, the light source 1 outputs control light 26 in a wavelength range different from the signal light 25.
01, and a multiplexer 102 is provided in the optical path on the incident side of the incident port 11. In the multiplexer 102, the control light 26 is multiplexed with the signal light 25. In the optical switch 103 according to the first embodiment (other embodiments are also possible), a light receiving element having a wavelength range of the control light 26 as a light receiving sensitivity area is used, and the light distribution of the control light 26 is measured by the light receiving element. Thus, the center of the optical axis of the signal light 25 is known. The signal light 25 and the control light 2 that have passed through the optical switch 103
6 is passed through the filter 104 so that only the signal light 25 is selectively passed.

If the control light 26 of another wavelength range is used for controlling the attitude of the mirror as described above, the loss of the original signal light 25 can be reduced, and the beam shape on the emission side is not affected. This has the effect.

Sixth Embodiment In the first to fifth embodiments, the light receiving element is formed in a series of processes for forming the lens array and the mirror array. However, the light receiving element is separately formed and the lens array and the mirror array are formed. The same effect can be obtained if both are integrated into an array by laminating the two after the formation.

Seventh Embodiment In the first to sixth embodiments, the light from the incident side mirror array is directly applied to the outgoing side mirror. However, as shown in FIG. An input port 11 in the input port array 1 and an output port 12 in the output port array 2 are formed, and one mirror array 9 is provided with the input side mirror 13 and the output side mirror array in the input side mirror array 3 of FIG. 4 and the exit side mirror 14 are formed. Then, the beam from the entrance port 11 is reflected by the entrance side mirror 13, further reflected by the total reflection mirror 7 provided separately, enters the exit side mirror 14 like the optical path 23, and is reflected by the exit side mirror 14. The emitted beam is guided to the emission port 12.

As described above, one substrate 8 and 9
The same effect can be obtained when a kind of port or mirror is formed.

Eighth Embodiment In the first to sixth embodiments, the incident-side lens array and the exit-side mirror array, and the incident-side mirror array and the exit-side lens array are separate arrays. As shown in FIG. 20, the array 91 includes the input port 11 of the input port array 1 of FIG. 1 and the output mirror 14 of the output millet array 4 in a mixed manner.
The output port 12 in the output port array 2 of FIG. 1 and the incident-side mirror 13 in the incident-side millet array 3 may be mixedly provided in the array 92 provided so as to be opposed to 1.

As can be seen from FIG. 20, the same effects as those described above can be obtained with a simple structure.

[0036]

According to the optical switch of the present invention, a light receiving element is provided at a movable portion or an output port of the optical path switching element, and by detecting the amount of light incident on the light receiving element, the light path switching element and the light path switching element can be connected even during line connection. The state of the light beam entering the exit port can be monitored directly and constantly. The output of the light receiving element can be applied to the control of the optical axis switching direction of the preceding optical path switching element on the incident side of the light receiving element, thereby reducing the insertion loss of the switch due to the mismatch between the optical axis and the mirror center. This has the effect of realizing a low-loss optical switch. further,
Since the change in the connection state of the line can always be known even during the line connection, the optical path switching element can be accurately controlled even in response to external vibration or the like, thereby preventing line disconnection.

Since three or more light receiving elements are arranged on the outer periphery of the light path switching element or the outgoing port, the beam center position of the light incident on the light path switching element can be determined by comparing the amounts of light incident on each light receiving element. It can be detected accurately.

By arranging the light path switching element as a translucent mirror and arranging a plurality of light receiving elements below the light path switching element, a part of the incident light can be received by the light receiving element, and the light on the emission side from the light path switching element can be received. There is an effect that the influence on the beam shape can be reduced. In addition, it is possible to accurately calculate the beam center position of the incident light from the comparison of the amounts of light incident on the respective light receiving elements.

By having the wavelength of the signal light of the line to be switched by the light receiving element in the light receiving sensitivity range, the beam center position of the light entering the optical path switching element can be provided without providing a separate light source in addition to the signal light entering the switch. There is an effect that a part of the signal light can be used when calculating.

The control light having a wavelength different from that of the original optical signal is multiplexed with the optical signal, and the intensity of the control light is detected by a light receiving element having light receiving sensitivity in the wavelength region of the control light. This has the effect of suppressing the signal loss of the signal light incident on the switch at the optical path switching element and reducing the influence on the beam shape of the light at the exit side from the optical path switching element.

By arranging the light receiving elements corresponding to the directions in which the movement of the beam center by each drive system can be controlled, it is possible to easily control the drive systems by comparing the outputs of the light receiving elements corresponding to each drive system. Can do.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical switch showing a first embodiment of the present invention.

FIG. 2 is a detailed view of an incident port array and an incident side mirror array in FIG.

FIG. 3 is a diagram showing a mirror mounting mechanism.

FIG. 4 is a diagram showing optical path switching of each mirror in the incident side mirror array.

FIG. 5 is a diagram showing the operation of each mirror in the exit-side mirror array.

FIG. 6 is a diagram showing a distribution of light intensity in a beam spot.

FIG. 7 is a diagram of a mirror having a light receiving element.

FIG. 8 is a diagram showing a state where a beam center is deviated from a mirror center.

9 is a graph showing the amount of incident light of each light receiving element in the situation of FIG.

FIG. 10 is a diagram showing a state in which a beam center coincides with a mirror center.

11 is a graph showing the amount of incident light of each light receiving element in the situation of FIG.

FIG. 12 is a diagram showing a rotation axis in a mirror;

FIG. 13 is a diagram showing a moving direction of an optical axis center on a mirror.

FIG. 14 is a schematic configuration diagram of an optical switch showing a second embodiment of the present invention.

FIG. 15 is a configuration diagram of a mirror used in a third embodiment of the present invention.

FIG. 16 is a configuration diagram of a mirror used in a third embodiment of the present invention.

FIG. 17 is a configuration diagram of a mirror having three light receiving elements used in a fourth embodiment of the present invention.

FIG. 18 is a control block diagram for multiplexing control light, which is employed in the fifth embodiment of the present invention.

FIG. 19 is a schematic configuration diagram of an optical switch showing a seventh embodiment of the present invention.

FIG. 20 is a schematic configuration diagram of an optical switch showing an eighth embodiment of the present invention.

FIG. 21 is a schematic configuration diagram of a conventional optical switch.

[Explanation of symbols]

Reference Signs List 1 entrance port array, 2 exit port array, 3 entrance mirror array, 4 exit mirror array, 7 total reflection mirror, 8 port array, 9 mirror array, 11
Input port, 12 output port, 13 input side mirror,
14 Exit-side mirror array, 15, 16 lens, 21
Input fiber, 22 Output fiber, 23 Optical path, 25 Optical signal, 26 Control light, 27a, 27b Gimbal mechanism, 30, 31, 32, 33, 34 Light receiving element, 4
1 translucent reflection mirror, 50 optical axis center, 61, 62
Rotation axis, 73 collimating lens, 76 optical axis, 91,
92 array, 101 control light source, 102 multiplexer, 1
04 Filter

Claims (6)

[Claims] 1. At least one incident side optical fiber,
An optical switch for interconnecting arbitrary fibers with at least one output fiber, an input port for converting incident light guided from each input optical fiber into a parallel beam, An output port for guiding light to each output side fiber, an optical path switching element for connecting between an optional input port and an optional output port by changing the optical path of a parallel beam, and an optical path by an optical path switching element. An optical switch, comprising: a light-receiving element for detecting a light-receiving amount provided at an output port or a second optical path switching element for receiving the changed parallel beam. 2. The light receiving element according to claim 1, wherein three or more of the light receiving elements are arranged on an outer peripheral portion of the output port or the second optical path switching element.
An optical switch as described. 3. The optical path switching element is a translucent mirror,
The optical switch according to claim 1, wherein the optical switch is arranged on a plurality of light receiving elements. 4. The optical switch according to claim 1, wherein the light receiving element has a wavelength of the optical signal in a light receiving sensitivity range. 5. A control light having a wavelength different from that of an optical signal is multiplexed with the optical signal, and the intensity of the control light is detected by a light receiving element having a light receiving sensitivity in a wavelength region of the control light. 4. The optical switch according to any one of 3. 6. The light-receiving element according to claim 1, wherein the plurality of light-receiving elements are arranged in a direction that can be controlled by a drive system for switching the optical axis direction of the optical path switching element in the preceding stage. Light switch.