JP2007310284A - Optical switch and protection switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make coupling efficiency constant between an incident end optical fiber and an exiting end optical fiber, in an optical switch or a protection switch. <P>SOLUTION: The length of each optical path between a first port and a second port group comprising a plurality of second ports is arranged to be constant respectively. A reflection part installed near the intersection of the optical axis of the first port and that of the second port is switched by an output from the outside, so that the optical axis of any second port and the optical axis of the first port are connected. As a result, a constant optical coupling efficiency is obtained by passing through any optical axis. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical switch and a protect switch in an optical communication device.

  Optical communication technology using optical fiber cables continues to advance for the purpose of high-speed and large-capacity communication. In addition, as a technology that supports stable high-speed and large-capacity communication, many contrivances have been made for methods and technologies related to line switching at the time of failure. For example, when the output side of an input or output port of one line breaks down, it is immediately switched to another output port so that communication is not interrupted to ensure communication safety.

An optical switch or a protect switch is used for such port switching. Patent Document 1 relates to an optical switch for switching a multi-channel optical signal. In the present invention, the optical path changing element is moved by magnetic force in order to select and switch the optical path of the input port and the optical paths of the plurality of output ports. The optical path changing element moves between two fixed magnets using a change in magnetic pole caused by electromagnetic induction. The optical path changing element is fixed by being brought into contact with one of the two magnets by magnetic force, thereby guiding an optical signal to a previously fixed input / output port.
JP 2001-235690 A

  In Patent Document 1, the reflection unit is moved by driving an electromagnet, thereby switching light. And since the some optical fiber was arrange | positioned in parallel in this optical path change part in parallel, there existed a fault that the distance between an incident side optical fiber and any one output side optical fiber was not constant.

  In a configuration in which light is collimated from an incident optical fiber via a collimator lens, and the light is collected by another collimator lens disposed on the optical axis and incident on the optical fiber again, the coupling efficiency is two collimator lenses. Depending on the distance between them, the coupling efficiency is maximized at one point. This is because even if a collimating lens is used, incident light cannot be made completely parallel light. Therefore, if the distance between the collimating lenses in the optical switch is different, there is a drawback that the coupling efficiency changes every time the switching is performed.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical switch and a protection switch whose coupling efficiency does not change even when the switch is switched.

  In order to solve this problem, an optical switch according to the present invention includes a first port that is a collimated beam input / output port and a plurality of collimated beam input / output ports that do not coincide with the optical axis of the first port. A second port group consisting of a plurality of second ports, an optical axis of the first port, and an optical axis of the first port, the optical axis of the first port, A plurality of reflecting portions that are switched by an external input between a first position that does not coincide with the first position and a second position that switches the optical axis of the first port to one of the second ports. The sum of the optical path length from the first port to the reflection position of each of the reflecting portions and the optical path length from the reflection position of each of the reflecting portions to each of the second ports is set to any optical axis of the second port. It is characterized by the fact that it remains constant even when selected

  In order to solve this problem, the protection switch of the present invention includes a first port that is an input / output port of a collimated beam and a plurality of input / output ports of a collimated beam that do not coincide with the optical axis of the first port. A second port group consisting of a plurality of second ports, a third port group consisting of a plurality of third ports facing each optical axis of the second port group, the optical axis of the first port, and the first port A first position which is arranged at an intersection position on each optical axis of two ports and does not coincide with the optical axes of the first and second ports, and the optical axis of the first port is one of the second ports. A plurality of reflecting portions that are switched by an external input to and from a second position that is switched to one optical axis, the optical path length from the first port to the reflecting position of each reflecting portion, and the reflection of each reflecting portion Husband with optical path length from position to each second port It is characterized in that the sum of is constant irrespective of the optical axis.

  Here, the optical path length from the first port to each second port of the second port group may be a predetermined range including the optical path length that maximizes the coupling efficiency.

  Here, the reflection unit may include a mirror and a rotary actuator that rotates the mirror, and may switch between the first position and the second position by an external input.

  According to the present invention having such a feature, since the distance between the collimating lenses is constant even when the optical switch and the protect switch are switched to any port, the light coupling efficiency is made constant. Can do. According to the second and fifth aspects of the invention, since the distance between the collimating lenses is set to the optimum position, an effect that the coupling efficiency can be kept high and constant can be obtained.

(Embodiment 1)
Next, an optical switch according to Embodiment 1 of the present invention will be described with reference to the drawings. In FIG. 1, an optical fiber 11 is an incident optical fiber, and an end thereof is connected to a collimator 12 to constitute a first port. The collimator 12 is a first collimator that makes light emitted from the optical fiber 11 parallel light. On the optical axis, a mirror group 13 including a plurality of, for example, six mirrors 13a to 13f is provided as shown. Each mirror 13a-13f is connected with rotary actuators 14a-14f as shown. The rotary actuators 14a to 14f have a rotation axis in the Z-axis direction perpendicular to the paper surface. The mirrors 13a to 13f are respectively fixed to the rotation axes, and the mirrors are rotated by rotating the axes. is there. Each mirror 13a-13f and rotary actuator 14a-14f comprise the reflection part which switches a reflection direction. Here, each of the mirrors 13a to 13f is assumed to rotate between a first position parallel to the X axis and a second position inclined by 45 ° with respect to the X axis as illustrated. The stoppers 15a to 15f are cylindrical members for holding the mirrors at a position of 45 ° with respect to the X axis by contacting the side walls of the actuators 14a to 14f, and are arranged in parallel to the Z axis. Yes. Here, the optical path length from the end of the first collimator 12 to the reflection point of the mirror 13a is L1a, the optical path length to the reflection point of the mirror 13b is L1b, and so on. The optical path lengths up to are L1c, L1d, L1e, and L1f.

  Then, when the light from the first port is reflected by the mirror in the direction parallel to the Y axis, the collimators 17a to 17f are respectively arranged at positions where the reflected light is received. The plurality of collimators 17a to 17f are parallel to the Y axis, and optical fibers 18a to 18f are connected to the collimators, respectively. Each collimator 17a-17f comprises the 2nd collimator group. Here, the respective optical path lengths from the reflection points from the mirrors 13a to 13f to the collimators 17a to 17f of the respective second collimator groups are denoted by L2a to L2f. The second collimator group is arranged so that the optical path lengths of the respective optical paths, that is, L1a + L2a, L1b + L2b, L1c + L2c, L1d + L2d, L1e + L2e, and L1f + L2f are all equal.

  Next, the operation of this embodiment will be described. As shown in FIG. 2A in the Z-axis direction and in FIG. 2B from the Y-axis direction in the initial state, the actuators are mirrors 13a to 13f. For example, in the state of FIG. To be. In this state, the mirrors 13 a to 13 f do not contact the optical axis from the collimator 12. Then, incident light is transmitted through the optical fiber 11, and parallel light is emitted from the optical collimator 12. Then, any one, for example, the rotary actuator 14c is rotated until it comes into contact with the stopper 15c. Thus, the mirror 13c is held as shown in FIGS. 3A and 3B in a state rotated by 45 ° from the X axis. The other mirrors are kept parallel to the X axis as shown in FIGS. 2A and 2B. In this state, the parallel light from the collimator 12 is reflected by the mirror 13c to become light parallel to the Y axis, and is guided from the collimator 17c to the optical fiber 18c.

  When switching light, the mirror 13c reflecting the light from the first collimator is rotated so as to be parallel to the X axis, and further rotated corresponding to any other mirror, for example, the mirror 13e. The mold actuator 14e is rotated until it contacts the stopper 15e. Then, the parallel light from the collimator 12 is reflected by the mirror 13e to become light parallel to the Y axis, and is guided from the collimator 17e to the optical fiber 18e. Thereby, the optical path of light can be switched.

  In the present embodiment, the optical path length from the first collimator to any one of the second collimator group does not change even if it passes through any optical path. Therefore, the optical coupling efficiency can be made constant regardless of which light path is switched.

FIG. 4 is a graph showing the relationship between the optical path length of the first collimator and the second collimator and the light coupling efficiency. As shown in this figure, the coupling efficiency becomes maximum at the optical path length Lmax. Therefore, if the optical path length from the collimating lens 12 to any one of the collimating lenses 17a to 17f is preferably a predetermined range including the maximum coupling efficiency, for example, the maximum coupling efficiency is 100%, the range L ₁₀ in which the coupling efficiency is 90% or more. ~L within _11, more preferably by keeping the optimum optical path length Lmax, it can also be bonded while maintaining a high coupling efficiency when passing through any route.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Also in the second embodiment, as in the first embodiment, the first position parallel to the X axis emitted from the first collimator, and the second position at 45 ° with respect to the Y axis and the X axis, The rotary actuators 14a to 14f and the mirrors 13a to 13f are arranged so as to rotate between the two. Furthermore, in Embodiment 2, the 3rd collimator group which consists of collimators 20a-20f is provided. Optical fibers 21a to 21f are connected to the collimators 20a to 20f, respectively. Here, the optical axis of the collimator 20a and the optical axis of the collimator 17a, the optical axis of the collimator 20b, the optical axis of the collimator 17b,. The optical path lengths L3a, L3b,... L3f from the reflection points of the mirrors 13a to 13f to the collimators in the third group are set equal to L1a, L1b,. The optical fibers 21a to 21f guide optical signals for six channels to the optical fibers 18a to 18f connected to the second collimator group.

  Next, the operation of the second embodiment will be described. In the second embodiment, incident optical signals for six channels are given to the collimators 20a to 20f via the optical fibers 21a to 21f, respectively. Light emitted from each collimator of the third collimator group enters the optical fibers 18a to 18f through the collimators 17a to 17f of the second collimator group, respectively. If any of the third collimator group and the optical communication device connected to the optical fiber is damaged, it is replaced with the light from the first collimator for backup. For example, when there is some failure in the path of the optical fiber 21b, the optical signal transmitted through the optical fiber 21b is transmitted to the optical fiber 11. Then, the rotary actuator 14b is rotated as shown in FIG. 3, and the reflection surface of the mirror 13b is rotated to a position of 45 ° with respect to the plane parallel to the X axis from the collimator 12. In this way, the light from the optical fiber 11 enters the collimator 17b via the collimator 12 and the mirror 13b, and is further transmitted to the optical fiber 18b. Therefore, a failure can be avoided. Similar processing is performed when another route fails.

  In this case, the optical path lengths L3a + L2a, L3b + 2b,... That pass through the space of light incident on the second group of collimators 17a-17f from the collimators 20a-20f are the same in all paths. Moreover, the distance from the switched first collimator to any one of the second collimators is also the same. Thus even use any path can be made constant optical coupling efficiency. Further, by setting the optical path length to the optimum optical path length Lmax as described above, each path can be configured with low insertion loss.

  In the first embodiment described above, the optical switch is configured such that light enters the second port from the first port. Alternatively, an optical switch may be used in which the incoming and outgoing directions are reversed and the light emitted from the second port is selected and given to the first port. In the second embodiment described above, the protection switch is configured to allow light to enter the second port from the third port. Alternatively, the protection switch may be configured such that the light emitted from the second port is given to the third port by reversing the incident and outgoing.

  Furthermore, in this embodiment, the path is switched by rotating the mirror. However, the path is moved by a minute distance along the Z axis, and the first position from the first port that does not receive the light from the first port and the first port. You may comprise so that arbitrary reflectors, such as a mirror or a prism, may be moved between the 2nd positions which inject light and reflect on the 2nd port side. Further, in each of the embodiments described above, the optical axis of the first port and the optical axis of the second port intersect at an angle of 90 ° on the XY plane, but this angle should also be an arbitrary angle. In this case, it goes without saying that it is necessary to arrange the reflector so that the light from the first port or the light from the second port is switched to the other port.

It is a figure which shows the structure of the optical switch by Embodiment 1 of this invention. It is a figure which shows the state which looked at the rotary actuator and the mirror from the Z-axis direction. It is a figure which shows the state which looked at the rotary actuator and the mirror from the Y-axis direction. It is a figure which shows the state which looked at the rotary actuator and the mirror from the Z-axis direction. It is a figure which shows the state which looked at the rotary actuator and the mirror from the Y-axis direction. It is a graph which shows the optical path length and coupling efficiency of each optical path from a 1st collimator to a 2nd collimator group. It is a figure which shows the structure of the protect switch by Embodiment 2 of this invention.

Explanation of symbols

11, 18a-18f, 21a-21f Optical fiber 12, 17a-17f, 20a-20f Collimator 13a-13f Mirror 14a-14f Rotary actuator 15a-15f Stopper

Claims (6)

A first port which is an input / output port of a collimated beam;
A second port group consisting of a plurality of second ports which are input / output ports of a plurality of collimated beams, each of which does not coincide with the optical axis of the first port;
A first position which is arranged at an intersection position on each optical axis of the first port and the second port and does not coincide with the optical axes of the first and second ports; and the light of the first port A plurality of reflecting portions that are switched by an external input between a second position for switching the axis to one optical axis of the second port;
Select the sum of the optical path length from the first port to the reflection position of each reflection part and the optical path length from the reflection position of each reflection part to each second port, and select any optical axis of the second port An optical switch characterized in that it is constant.   2. The optical switch according to claim 1, wherein the optical path length from the first port to each second port of the second port group is a predetermined range including an optical path length that maximizes coupling efficiency. The reflective portion is
Mirror,
A rotary actuator for rotating the mirror,
3. The optical switch according to claim 1, wherein the first position and the second position are switched by an external input. A first port which is an input / output port of a collimated beam;
A second port group consisting of a plurality of second ports which are input / output ports of a plurality of collimated beams, each of which does not coincide with the optical axis of the first port;
A third port group comprising a plurality of third ports facing each optical axis of the second port group;
A first position that is disposed at an intersection position on the optical axis of the first port and the optical axis of the second port and does not coincide with the optical axis of the first and second ports; and the light of the first port A plurality of reflecting portions that are switched by an external input between a second position for switching the axis to one optical axis of the second port,
The sum of the optical path length from the first port to the reflection position of each reflection portion and the optical path length from the reflection position of each reflection portion to each second port is constant regardless of the optical axis. Protect switch.   5. The protection switch according to claim 4, wherein an optical path length from the first port to each second port of the second port group is a predetermined range including an optical path length that maximizes coupling efficiency. The reflective portion is
Mirror,
A rotary actuator for rotating the mirror,
6. The protection switch according to claim 4, wherein the first position and the second position are switched by an external input.

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