JP2015055781A - Wavelength selection switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease influences on an unintended port during a non-operation period when a deflection element is not driven.SOLUTION: In a port array 11, a plurality of ports including an input port 11a and output ports 11b to 11f is arranged in an X direction at intervals including a first interval S1 and a second interval S2 wider than the first interval S1. A spectral element spectrally disperses wavelength-multiplexed light input from the input port 11a into a Y direction to output a plurality of wavelength component beams. A deflection element 16 deflects the light output from the spectral element into a predetermined direction. In a non-operation period when the deflection element 16 is not driven, a deflected beam Da deflected by the deflection element 16 based on the light input from the input port 11a is guided to a retreat position P1 to retreat from the plurality of ports 11a to 11f in the X direction. The retreat position P1 is determined in such a manner that a deflected beam Db to Df deflected by the deflection element 16 based on light input from any of the ports 11b to 11f excluding the input port 11a in the non-operation period is not guided to between the ports adjoining to each other at the first interval S1.

Description

  The present invention relates to a wavelength selective switch.

  In the field of wavelength division multiplexing optical communication, a reconfigurable optical add drop multiplexer (ROADM) is known. In this apparatus, a wavelength selective switch (WSS) having a spectroscopic element that splits signal light including a plurality of different wavelength components and a deflecting element that deflects the split wavelength component light in different directions is provided. Used. The wavelength selective switch is arranged at each node constituting the optical network.

  When a failure occurs in a certain node or path, the wavelength selective switch transmits signal light via the node or path in which no failure occurs so that communication of the entire network is not impaired. At this time, in a wavelength selective switch arranged in a node that does not participate in communication or cannot communicate, it is necessary to prevent an unintended network connection state from occurring by disconnecting the connection between the input port and the output port.

  For example, the wavelength selective switch described in Patent Document 1 includes a port array in which a plurality of ports including an input port and an output port are arranged. When the deflecting element is not driven, the light deflected by the deflecting element is guided to a predetermined position where it does not enter the port array, and the optical connection between the input port and the output port is disconnected. .

Japanese Patent No. 4656135 U.S. Patent No. 7826697 International Publication No. 2011/100605 Pamphlet

  When light is input from a port other than the input port for some reason, even when the optical connection between the input port and the output port is cut off when the deflection element is not driven. May cause light coupling to unintended ports.

  An object of the present invention is to provide a technique capable of reducing the influence on an unintended port even in such a case.

In order to achieve the above object, one aspect of the present invention is a wavelength selective switch,
A port array in which a plurality of ports including an input port and an output port are arranged in a first direction including a first interval and a second interval wider than the first interval;
A spectral element that splits wavelength-multiplexed light input from the input port in a second direction different from the first direction, and outputs a plurality of wavelength component lights;
A deflecting element that deflects light output from the spectroscopic element in a predetermined direction,
When the deflecting element is not driven, the first deflected light deflected to the deflecting element based on the light input from the input port is guided to a retreat position that avoids the plurality of ports in the first direction. ,
The retracted position is such that the second deflected light deflected to the deflecting element based on light input from any of the plurality of ports excluding the input port during the non-operation is adjacent to the first interval. It is determined not to be led between a plurality of ports.

  According to such a configuration, the influence on an unintended port can be reduced when the deflecting element is not driven.

It is a figure which shows typically the wavelength selective switch which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the optical system with which a wavelength selection switch is provided. It is a figure for demonstrating the definition of the beam size of deflection | deviation light. It is a schematic diagram which shows the structure of the port array with which the wavelength selective switch which concerns on 1st Embodiment is provided. It is a schematic diagram which shows the structure of the port array which concerns on a 1st comparative example. It is a schematic diagram which shows the structure of the port array with which the wavelength selection switch concerning 2nd Embodiment is provided. It is a schematic diagram which shows the structure of the port array which concerns on a 2nd comparative example.

  Embodiments according to the present invention will be listed and described.

(1): a wavelength selective switch,
A port array in which a plurality of ports including an input port and an output port are arranged in a first direction including a first interval and a second interval wider than the first interval;
A spectral element that splits wavelength-multiplexed light input from the input port in a second direction different from the first direction, and outputs a plurality of wavelength component lights;
A deflecting element that deflects light output from the spectroscopic element in a predetermined direction,
When the deflecting element is not driven, the first deflected light deflected to the deflecting element based on the light input from the input port is guided to a retreat position that avoids the plurality of ports in the first direction. ,
The retracted position is such that the second deflected light deflected to the deflecting element based on light input from any of the plurality of ports excluding the input port during the non-operation is adjacent to the first interval. A wavelength selective switch that is designed not to be routed between multiple ports.

  According to such a configuration, the influence on an unintended port can be reduced when the deflecting element is not driven.

  (2) In the wavelength selective switch according to (1), the retracted position is determined so that the second polarized light is not coupled to two or more of the plurality of ports.

  According to such a configuration, even when the second polarized light is combined with any of the plurality of ports, the influence on the unintended port can be minimized.

  (3): The wavelength selective switch according to (2), wherein the second polarized light guided to a region coupled to any one of the plurality of ports is prevented from coupling to the port. The unit is further provided.

  According to such a configuration, it is possible to reliably avoid a situation in which the second polarized light is combined with an unintended port.

  (4) In the wavelength selective switch according to (3), the number of the attenuation units is smaller than the number of the output ports.

  According to such a configuration, it is possible to minimize the number of attenuation portions, and it is possible to reduce the component cost and reduce the size of the optical system.

  (5): The wavelength selective switch according to (3) or (4), further including a control unit that controls the attenuating unit, wherein the control unit transmits the second polarized light to any of the plurality of ports. When it is led to a position where it is connected to the heel, the attenuating portion is selectively operated.

  According to such a configuration, it is possible to avoid that the deflected light generated during the operation of the deflecting element is hindered by the attenuation unit.

  (6): The wavelength selective switch according to any one of (1) to (5), in which the first deflected light and the second deflected light reenter the condensing optical system.

  According to such a configuration, the path of the subsequent deflected light can be placed under the control of the optical system by intentionally re-entering the deflected light into the condensing optical system. As a result, the path of the deflected light can be easily specified, and the retreat position can be easily managed.

  (7): The wavelength selective switch according to any one of (1) to (6), further including a substrate that supports at least one of a plurality of optical components including the port array and the spectroscopic element, The first polarized light passes through a gap formed between at least one of the optical components and the substrate.

  According to such a configuration, the optical system can be miniaturized by effectively utilizing, for example, a gap formed by the support structure of the optical component in determining the optical path of the deflected light reaching the retracted position.

  A more specific example of an embodiment according to the present invention will be described below in detail with reference to the accompanying drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size.

  FIG. 1 schematically shows a configuration of the wavelength selective switch 1 according to the first embodiment viewed from the X direction as an example of the first direction. FIG. 2 schematically shows the configuration of the wavelength selective switch 1 viewed from the Y direction as an example of the second direction.

  As shown in FIG. 1, the wavelength selective switch 1 includes a port array 11, a collimator array 12, an anamorphic optical system 13, a spectroscopic element 14, a condensing lens 15, and a deflecting element 16.

  As illustrated in FIG. 2, the port array 11 includes a plurality of ports 11a to 11f arranged in the X direction. Each port 11a to 11f is used as an input port or an output port. The input port receives wavelength multiplexed light as input light. The output port outputs predetermined wavelength component light as output light. Each of the ports 11a to 11f includes an optical waveguide such as an optical fiber.

  Which port is assigned to an input port or an output port is arbitrary. In the example shown in FIG. 2, the port 11a arranged at the end of the port array 11 is assigned to an input port, and the remaining ports 11b to 11f are assigned to output ports. A port arranged at a position other than the end of the port array may be assigned to the input port.

  The collimator array 12 is an optical element that collimates the light input from the port array 11. For example, a lens array in which lenses having arbitrary refractive indexes in the X direction and the Y direction are arranged corresponding to the respective ports 11a to 11f.

  The anamorphic optical system 13 converts the cross-sectional shape in the XY plane of the light collimated by the collimator array 12 so as to have different magnifications in the X direction and the Y direction. For example, it includes a pair of prisms 13a and 13b that expand incident light in the Y direction. That is, the cross-sectional shape in the XY plane of the light output from the anamorphic optical system 13 is an ellipse that is flat in the Y direction.

  The anamorphic optical system 13 may reduce incident light in the X direction as long as the cross-sectional shape of the output light in the XY plane is an ellipse that is flat in the Y direction. The anamorphic optical system 13 may be configured by using at least one optical component (such as a cylindrical lens or a cylindrical mirror) having an arbitrary refractive index in the X direction or the Y direction.

  The spectroscopic element 14 is an optical element that splits wavelength-multiplexed input light in the Y direction and outputs a plurality of wavelength component lights. The spectroscopic element 14 is, for example, a transmissive diffraction grating. In the example shown in FIG. 1, the wavelength multiplexed light L0 including the wavelengths λ1, λ2, and λ3 passes through the spectroscopic element 14, so that the light L1 including the wavelength λ1 and the light L2 including the wavelength λ2 are examples of the wavelength component light. , And light L3 including wavelength λ3. These are output at different angles depending on the wavelength in the Y direction.

  A condensing lens 15 as an example of a condensing optical system is disposed between the spectroscopic element 14 and the deflecting element 16. The condenser lens 15 is configured to couple each wavelength component light output from the spectroscopic element 14 to the deflection element 16.

  At this time, the light expanded in the Y direction by the anamorphic optical system 13 is reduced in the Y direction by the condenser lens 15. When light is reduced in the X direction by the anamorphic optical system 13, the condenser lens 15 expands incident light in the X direction. In any case, the cross-sectional shape in the XY plane of each wavelength component light in the deflection element 16 is an ellipse that is flat in the X direction.

  The deflecting element 16 includes deflecting units 16 a to 16 e arranged in the Y direction, and is provided corresponding to each wavelength component light dispersed by the spectroscopic element 14. Each of the deflecting units 16a to 16e can independently deflect each wavelength component light. In the example shown in FIG. 1, the deflecting units 16a, 16b, and 16c are arranged at positions where they are combined with the light beams L1, L2, and L3 of the respective wavelength component lights including the wavelengths λ1, λ2, and λ3, respectively.

  The wavelength selective switch 1 includes a drive unit 17 that is communicably connected to the deflection element 16. The drive unit 17 independently controls the direction (deflection angle) of light deflected by each of the deflecting units 16a to 16e. For example, the drive unit 17 is electrically connected to the deflection units 16a to 16e, and controls the deflection angles by independently controlling the applied voltages to the deflection units 16a to 16e.

  In the present embodiment, the deflection element 16 is, for example, a mirror array, and each of the deflection units 16a to 16e is a reflecting surface of a movable mirror. Each movable mirror is, for example, a MEMS (micro-electro-mechanical systems) mirror. The movable mirror rotates around the X axis and the Y axis, and the tilt angle of the reflecting surface can be controlled. By changing the direction of the reflecting surface in the X direction and the Y direction, the traveling direction of the deflected light can be changed independently.

  The deflection element 16 is not limited to a MEMS mirror. Use a reflective liquid crystal element such as LCOS (Liquid Crystal on Silicon), a transmissive liquid crystal element, or a DMD (Digital Mirror Device) that can change the traveling direction of the deflected light at least in the X direction depending on the applied voltage. Is possible.

  The wavelength component lights L1, L2, and L3 deflected by the deflecting units 16a, 16b, and 16c pass through the condensing lens 15, the spectroscopic element 14, the anamorphic optical system 13, and the collimator array 12, respectively. 11 is input. In the example shown in FIG. 2, the light L1 enters the port 11c, the light L2 enters the port 11d, and the light L3 enters the port 11e.

  Therefore, as a result of the wavelength multiplexed light L0 including at least the wavelengths λ1, λ2, and λ3 being input to the port 11a, the light L1 including the wavelength λ1, the light L2 including the wavelength λ2, and the light L3 including the wavelength λ3 are respectively connected to the port 11c. , 11d and 11e.

  As indicated by a one-dot chain line in FIG. 2, the light Lb deflected by the deflecting element 16 based on the light input from the port 11a when the deflecting element 16 is not driven (when the power is turned off) is not X direction. Are guided to a retracted position P that avoids the ports 11a to 11f.

  More specifically, when the power supply to the drive unit 17 is cut off, the orientation of the reflecting surfaces of the deflecting units 16a to 16e is in the initial state. This initial state corresponds to the state of the reflecting surfaces of the deflecting units 16a to 16e that guide the deflected light Lb based on the light input from the port 11a to the retracted position P. In other words, the retracted position P is a position that ensures that the deflected light Lb based on the light input from the port 11a as an example of the input port is not coupled to any port included in the port array 11. A light absorbing member may be disposed at the retracted position P.

Here, the shape and arrangement of the condenser lens 15 are determined so that the light Lb deflected by the deflecting element 16 in the non-driven state based on the light input from the port 11a reenters the condenser lens 15. ing. It should be noted that the part where the deflected light Lb is incident on the condenser lens 15 is configured to be different from the part where the wavelength component lights L1 to L3 are incident.

  In this way, the deflected light Lb is intentionally re-incident on the condenser lens 15, so that the path of the subsequent deflected light Lb is placed under the control of the optical system. As a result, the path of the deflected light Lb can be easily specified, and the retreat position P can be easily managed.

  Each of the port array 11, the collimator array 12, the anamorphic optical system 13, and the spectroscopic element 14 is supported so as to form a gap G with the optical substrate 20 by an appropriate support structure. The light Lb deflected by the deflection element 16 passes through the gap G and reaches the retracted position P.

  According to such a configuration, since the gap G formed by the support structure of the optical component can be effectively used for guiding the deflected light Lb to the retracted position P, the optical system can be downsized.

  Next, a configuration in which the wavelength selective switch according to the present embodiment prevents light coupling to an unintended port will be described. As shown in FIG. 3, the deflected light has a spread in which the intensity changes depending on the distance from the beam center. “Light coupling” refers to a state in which light having a threshold intensity (for example, an intensity at which the optical attenuation with respect to the maximum light intensity is 25 Da) or more enters one of the ports. For example, when the beam size BS is defined as twice the value obtained from the intersection of the threshold intensity and the light intensity distribution curve, “light coupling” means the outer edge of the port (for example, the effective diameter of each lens constituting the collimator array 12). This indicates a state in which the distance between the outer edge to be determined and the beam center is equal to or less than half of the beam size BS.

  As shown in FIG. 4, the port array 11 includes a plurality of ports 11a to 11f arranged in the X direction including a first interval S1 and a second interval S2 wider than the first interval S1. Here, the “interval” corresponds to a distance between centers of adjacent ports in the X direction.

  Reference numeral P1 indicates that the deflected light Lb deflected by the non-driven deflecting element 16 based on the light incident from the port 11a used as the input port passes through the ports 11a to 11f in the middle of the path to the retracted position P. It represents the position that intersects the connecting straight line. The distance between the center of the adjacent port 11f in the X direction and the position P1 is defined as a third interval S3.

  A circle indicated by a broken line represents the beam size BS of the deflected light at the port array 11 or the position P1. That is, when at least a part of the circle indicated by the broken line overlaps with the circle indicating the port, it indicates that the deflected light corresponding to the broken line is coupled to the port.

  As described above, when the deflecting element 16 is not driven, the light incident from the port 11a used as the input port is guided to the retreat position P that avoids the ports 11a to 11f. In other words, the posture of the deflecting element 16 during non-operation is determined so that the light incident from the port 11a can be guided to the position P1. Therefore, if light is unexpectedly input to 11b to 11f used as output ports at this time, the light deflected by the deflecting element 16 in a non-operating state may be combined with an unintended output port. is there.

  Therefore, in the present embodiment, the light input from any of the ports 11b to 11f in a state where the deflected light (an example of the first deflected light) based on the light input from the port 11a is guided to the retracted position P. The retracted position P is determined so that the deflected light based on the above (an example of the second deflected light) is not guided between the adjacent ports at the first interval S1. That is, the light Db to Df deflected to the deflecting element 16 based on the light input from any of the ports 11b to 11f excluding the port 11a used as the input port is between the ports 11a and 11b and between the ports 11c and 11d. The position P1 is determined so as not to be led between the ports 11e and 11f.

  This will be described more specifically. In the state where the deflected light Da based on the light input from the port 11a is guided to the position P1, when there is an unintended light input from the port 11b used as the output port, the deflecting element 16 in the non-operating state. The polarized light Db generated by is guided between the port 11f and the retracted position P (P1). The deflected light Da is not coupled to the port 11f.

  Under the same conditions, when there is an unintended light input from the port 11f used as the output port, the deflected light Df generated by the deflecting element 16 in the non-operating state is guided between the port 11b and the port 11c. It is burned. The deflected light Df is coupled only to the port 11b.

  Under the same conditions, when there is an unintended light input from the port 11e used as the output port, the deflected light De generated by the deflecting element 16 in the non-operating state is guided between the port 11b and the port 11c. It is burned. The deflected light De is coupled only to the port 11c.

  Under the same conditions, when there is an unintended light input from the port 11d used as the output port, the deflected light Dd generated by the deflecting element 16 in the non-operating state is guided between the port 11d and the port 11e. It is burned. The deflected light Dd is coupled only to the port 11d.

  Under the same conditions, when there is an unintended light input from the port 11c used as the output port, the deflected light Dc generated by the deflecting element 16 in the non-operating state is guided between the port 11e and the port 11f. It is burned. The deflected light Dc is coupled only to the port 11e.

  Under the same conditions, when there is an unintended light input from the port 11b used as the output port, the deflected light Db generated by the deflecting element 16 in the non-operating state is between the port 11f and the retracted position P. Led. The deflected light Db is coupled only to the port 11f.

  That is, even when unintended light is input from any of the ports 11b to 11f used as output ports when the deflecting element 16 is not driven, the deflected light generated based on the light is transmitted from the ports 11a to 11f. Simultaneous coupling to a plurality of ports of 11f is prevented. As a result, the influence of the deflected light on an unintended port can be reduced. In other words, by permitting coupling to any one port, the port interval is narrowed to reduce the size of the port array 11, while minimizing the influence on unintended ports.

  In the above-described example, each deflected light input from a port used as an output port and generated based on light is coupled to only one of the ports. However, the deflected light may be configured not to be coupled to any port. For example, the second interval S2 may be set to be larger than the beam size BS so as not to be coupled to any adjacent port at the second interval S2.

  FIG. 5 shows a wavelength selective switch 101 according to a first comparative example. In the wavelength selective switch 101, in a state where the deflected light based on the light input from the port 11a used as the input port is guided to the retreat position P, from any of the ports 11b to 11f used as the output port. Part of the deflected light (Dc and De) based on the input light is also guided between adjacent ports at the first interval S1.

  As described above, when the deflected light is guided between the adjacent ports at the interval S1 narrower than the second interval S2, a situation in which the deflected light is combined with a plurality of ports may occur. In that case, the influence on the coupling of the deflected light to the unintended output port becomes large. As in the wavelength selective switch 1 according to the first embodiment, the retreat position P is determined so that the deflected light generated by the deflecting element 16 that is not in operation is not guided between the adjacent ports at the first interval S1. Thus, such a situation can be avoided.

  Next, a wavelength selective switch 1A according to the second embodiment will be described. The wavelength selective switch 1A is different from the wavelength selective switch 1 according to the first embodiment in that the wavelength selective switch 1A includes an attenuation unit 18 and a control unit 19 indicated by broken lines in FIG. The second interval S2 is set to be larger than the beam size BS, and the deflected light guided between adjacent ports at the second interval S2 is configured not to be coupled to any port. Since the other points are the same as those of the wavelength selective switch 1, repeated description is omitted.

  The attenuation unit 18 is an optical element configured to attenuate the intensity of light passing therethrough. The attenuation unit 18 is, for example, a shutter that prevents light from passing (attenuates light intensity to substantially zero), and in addition to a movable shutter that inserts a material made of a material that does not have optical transparency into the optical path, A liquid crystal element or a ferroelectric crystal whose light transmittance can be controlled by applying a polarizing filter or a driving voltage can be used.

  The control unit 19 is communicably connected to the drive unit 17 and can recognize that the deflection element 16 is in a non-operating state. The control unit 19 selects the attenuating unit 18 when the deflected light (an example of the second deflected light) generated by the deflecting element 16 in the non-operating state is led to a position where it is combined with any of the ports 11a to 11f. And is configured to block the coupling of the deflected light to the port. Here, “actuation” means that the attenuating unit is in a state of exhibiting the light attenuating function.

  FIG. 6 shows a state in which the attenuation unit 18 is activated. The deflected light Da based on the light input from the port 11a is guided to the retracted position P (P1). In this state, when there is an unintended light input from the port 11f used as the output port, the deflected light Df generated by the deflecting element 16 in the non-operating state is guided between the port 11b and the port 11c. . The polarized light Df is not coupled to any port.

  Under the same conditions, when there is an unintended light input from the port 11e used as the output port, the deflected light De generated by the deflecting element 16 in the non-operating state enters the attenuator 18. As a result, the coupling of the deflected light De to the port 11c is prevented. As a result, the polarized light De is not coupled to any port.

  Similarly, when there is an unintended light input from the port 11c used as the output port, the input light enters the attenuator 18. As a result, the input light is prevented from reaching the deflecting element 16 and the occurrence of the deflected light Dc is prevented.

  Under the same conditions, when there is an unintended light input from the port 11d used as the output port, the deflected light Dd generated by the deflecting element 16 in the non-operating state is guided between the port 11d and the port 11e. It is burned. The polarized light Dd is not coupled to any port.

  Under the same conditions, when there is an unintended light input from the port 11b used as the output port, the deflected light Db generated by the deflecting element 16 in the non-operating state is between the port 11f and the retracted position P. Led. The polarized light Db is not coupled to any port.

  According to such a configuration, it is possible to avoid the coupling of the deflected light generated by the deflecting element 16 in the non-operating state to an unintended port.

  FIG. 7 shows a wavelength selective switch 101A according to a second comparative example. The wavelength selective switch 101A includes an attenuation unit 18A having a configuration different from that of the attenuation unit 18 included in the wavelength selective switch 1A according to the second embodiment. Other configurations are the same as those of the wavelength selective switch 101 according to the first comparative example. That is, in the state where the deflected light based on the light input from the port 11a used as the input port is guided to the retracted position P, the light input from any of the ports 11b to 11f used as the output port is used. A part of the deflected light (Dc and De) is also guided between the adjacent ports at the first interval S1.

  In such a case, even if the second interval S2 is sufficiently larger than the beam size BS, the deflected light guided between the adjacent ports at the interval S1 narrower than the second interval S2 is combined with the plurality of ports. Things can happen. On the other hand, if the first interval S1 is sufficiently larger than the beam size BS, the size of the port array 11 in the X direction becomes large, and it is difficult to reduce the size of the apparatus.

  For example, in FIG. 7, the deflected light De generated based on the light input from the port 11e is guided between the adjacent ports 11c and 11d at the first interval S1. Therefore, it is necessary to provide the attenuation portion 18A so as to prevent not only the connection to the port 11c but also the port 11d. That is, it is necessary to provide an attenuation unit 18A having a larger number or size than the wavelength selective switch 1A according to the second embodiment.

  In the wavelength selective switch 1A according to the second embodiment, the retracted position P is determined so that the deflected light generated by the deflecting element 16 that is not in operation is not guided between adjacent ports at the first interval S1. Therefore, this situation can be avoided. In other words, it is possible to minimize the number and size of the attenuation portions 18. For example, as shown in FIG. 6, the number of attenuation units 18 may be smaller than the number of ports 11 b to 11 f used as output ports. Therefore, it is possible to reduce the cost of components and downsize the optical system.

  The above embodiment is for facilitating understanding of the present invention, and does not limit the present invention. The present invention can be modified and improved without departing from the spirit of the present invention, and it is obvious that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 1, 1A: Wavelength selection switch 11: Port array 11a-11f: Port 12: Collimator array 13: Anamorphic optical system 13a: Prism 13b: Prism 14: Spectroscopic element 15: Condensing lens 16: Deflection element 16a-16e: Deflection unit 17: Drive unit 18: Attenuation unit 19: Control unit 20: Optical substrate BS: Beam size Da to Df: Deflection light L1: Light including wavelength λ1 L2: Light including wavelength λ2 L3: Light including wavelength λ3 P : Retraction position S1: First interval S2: Second interval S3: Third interval

Claims (7)

A port array in which a plurality of ports including an input port and an output port are arranged in a first direction including a first interval and a second interval wider than the first interval;
A spectral element that splits wavelength-multiplexed light input from the input port in a second direction different from the first direction, and outputs a plurality of wavelength component lights;
A deflecting element that deflects light output from the spectroscopic element in a predetermined direction,
When the deflecting element is not driven, the first deflected light deflected to the deflecting element based on the light input from the input port is guided to a retreat position that avoids the plurality of ports in the first direction. ,
The retracted position is such that the second deflected light deflected to the deflecting element based on light input from any of the plurality of ports excluding the input port during the non-operation is adjacent to the first interval. A wavelength selective switch that is designed not to be routed between multiple ports.   2. The wavelength selective switch according to claim 1, wherein the retracted position is determined so that the second polarized light is not coupled to two or more of the plurality of ports.   The wavelength selective switch according to claim 2, further comprising an attenuating unit that prevents the second polarized light guided to a region coupled to any one of the plurality of ports from coupling to the port.   The wavelength selective switch according to claim 3, wherein the number of the attenuating units is smaller than the number of the output ports. A control unit for controlling the attenuation unit;
5. The wavelength selective switch according to claim 3, wherein the control unit selectively activates the attenuating unit when the second polarized light is guided to a position where it is combined with any of the plurality of ports. 6. Further comprising a condensing optical system for coupling the wavelength component light to the deflection element;
6. The wavelength selective switch according to claim 1, wherein the first deflected light and the second deflected light reenter the condensing optical system. A substrate that supports at least one of a plurality of optical components including the port array and the spectroscopic element;
The wavelength selective switch according to claim 1, wherein the first polarized light passes through a gap formed between at least one of the optical components and the substrate.