JP2015059978A - Wavelength selective switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength selective switch capable of reducing a quantity of leaked light to a port other than an output port to be coupled.SOLUTION: A wavelength selective switch 1 includes: an input/output optical system 18 including an input port 11 and output ports 12a to 12d; a spectral element 15 that spectrally divides light L and outputs wavelength components L21 to L23; a light deflecting element 17 that deflects the wavelength components L21 to L23; a condensing element 16 that couples the wavelength components L21 to L23 to the light deflecting element 17; and a control unit 20 that controls a deflection angle and thereby controls a threshold of optical coupling efficiency of a predetermined wavelength component L22 to a predetermined output port 12c. The control unit 20 sets a maximum in the threshold of optical coupling efficiency of the light L22 to be different from an optimal coupling state.

Description

  The present invention relates to a wavelength selective switch.

  In Patent Document 1, in a wavelength selective switch (WSS), the angle of a movable mirror that reflects light is shifted in the spectral direction or the like, and the beam optical axis at the output port is shifted in the X-axis direction and the Y-axis direction. Thus, a technique for attenuating the intensity of output light is disclosed.

JP 2009-047917 A

  The wavelength selective switch has a problem that the beam is expanded at the output port of the coupling destination due to the defocusing of the light at the output port, and the light is coupled to other ports. If the interval between the output ports is increased, the amount of such leakage light can be reduced, but the arrangement density of the ports cannot be increased, and it becomes difficult to downsize the wavelength selective switch.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wavelength selective switch that can reduce the amount of leakage light to ports other than the output port of the coupling destination.

  As one aspect of the present invention, an input / output optical system including at least one input port and a plurality of output ports, and a spectroscopic element that splits light input from the input port for each wavelength component and outputs the wavelength component An optical deflecting element that deflects each wavelength component output from the spectroscopic element and sets a deflection angle so as to be coupled to a predetermined output port; and the wavelength component output from the spectroscopic element is the light. A condensing optical system coupled to a deflecting element; and a control unit that controls a threshold of optical coupling efficiency of the predetermined wavelength component to the predetermined output port by controlling the deflection angle. The unit is a wavelength selective switch that sets a maximum value of the threshold value of the optical coupling efficiency different from the optimum coupling state.

  ADVANTAGE OF THE INVENTION According to this invention, the wavelength selective switch which reduced the quantity of the leakage light with respect to ports other than the output port of a connection destination can be provided.

It is a top view which shows roughly the structure of the wavelength selective switch which concerns on one Embodiment of this invention. It is a sectional side view along the II-II line of the wavelength selective switch shown in FIG. It is a figure which shows typically the control which reduces leakage light in the input-output port of the wavelength selective switch shown by FIG. It is a figure for demonstrating the control method for reducing leakage light in a wavelength selective switch. It is a figure which shows typically another control which reduces leakage light in the input-output port of a wavelength selective switch. It is a figure for demonstrating an example of the control method for reducing the leak light from two adjacent ports. It is a figure which shows typically another control which reduces leakage light in the input-output port of a wavelength selective switch. It is a figure which shows the example of the two-dimensional arrangement | sequence of the input / output port of a wavelength selection switch. It is a figure which shows typically the control which reduces leakage light in the input-output port arranged two-dimensionally. It is a figure which shows LCOS as an example of an optical deflection | deviation element.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.

  As one aspect of the present invention, an input / output optical system including at least one input port and a plurality of output ports, and a spectroscopic element that splits light input from the input port for each wavelength component and outputs the wavelength component An optical deflecting element that deflects each wavelength component output from the spectroscopic element and sets a deflection angle so as to be coupled to a predetermined output port; and the wavelength component output from the spectroscopic element is the light. A condensing optical system coupled to a deflecting element; and a control unit that controls a threshold of optical coupling efficiency of the predetermined wavelength component to the predetermined output port by controlling the deflection angle. The unit is a wavelength selective switch that sets a maximum value of the threshold value of the optical coupling efficiency different from the optimum coupling state.

  In the wavelength selective switch, the optical coupling efficiency to each output port changes in a quadratic function shape (parabolic shape) depending on the port position (see FIG. 4). Therefore, in controlling the threshold value of the optical coupling efficiency to the predetermined output port, the maximum value is set to be different from the optimum coupling state, so that the light input to the predetermined output port (for example, FIG. 4). The attenuation amount of light (for example, the adjacent port in FIG. 4) input to the adjacent port can be made larger than the attenuation amount with respect to the optimum coupling state of the coupling destination port). For this reason, it is possible to provide a wavelength selective switch in which the amount of leakage light with respect to ports other than the output port of the coupling destination is reduced.

  In the wavelength selective switch, the output port includes an optical waveguide member and an optical coupling member that couples the wavelength component to an end surface of the optical waveguide member, and the control unit is coupled to the optical coupling member. The maximum value is set by setting the deflection angle so that the optical axis of the wavelength component and the optical axis of the optical coupling member are shifted from each other, and further, the predetermined output port and the other output ports The deflection angle of the predetermined wavelength component may be controlled along a virtual straight line connecting the output port adjacent to the predetermined output port. In this case, in the wavelength selective switch in which each port is uniaxially arranged, it is possible to reduce the amount of leakage light with respect to ports other than the output port of the coupling destination.

  In the wavelength selective switch, the output port includes an optical waveguide member and an optical coupling member that couples the wavelength component to an end surface of the optical waveguide member, and the control unit is coupled to the optical coupling member. The maximum value is set by setting the deflection angle so that the optical axis of the wavelength component and the optical axis of the optical coupling member are shifted from each other, and further, the predetermined output port and the other output ports The deflection angle of the predetermined wavelength component may be controlled along a straight line orthogonal to a virtual straight line connecting the output port adjacent to the predetermined output port. In this case, it is possible to reduce the amount of light leaked to a plurality of ports adjacent to the output port of the coupling destination.

  In the wavelength selective switch, the control unit may perform the predetermined wavelength component so as to optically couple on a line having the same distance from two output ports adjacent to the predetermined output port among the plurality of output ports. The deflection angle may be controlled. In this case, it is possible to minimize the amount of light leaked to the port adjacent to the output port of each connection destination.

  In the wavelength selective switch, the control unit is configured to perform predetermined optical coupling so that leakage light amounts of the other wavelength components input to the two output ports adjacent to the predetermined output port are equal. The deflection angle of the wavelength component may be controlled. In this case, for example, if the ports are arranged at equal intervals, the maximum value in the threshold value of the optical coupling efficiency is obtained by monitoring the amount of light leaked from two ports adjacent to the output port of the coupling destination. Can be adjusted easily.

  In the wavelength selective switch, the plurality of output ports have two end surfaces arranged in a two-dimensional manner, and the control unit has three adjacent output ports adjacent to the predetermined output port as vertices. The deflection angle of the predetermined wavelength component may be controlled in the outer direction of the triangle.

  In the wavelength selective switch, it is preferable that the control unit controls the deflection angle so that the predetermined wavelength component is separated from the output port closest to the predetermined output port. In this case, the amount of light leaked to the nearest output port with the largest amount of light leaked can be effectively reduced.

[Details of the embodiment of the present invention]
A specific example of a wavelength selective switch according to an embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and it is intended that all the changes are included within the meaning and range equivalent to the claim.

  FIG. 1 is a plan view schematically showing a configuration of a wavelength selective switch according to an embodiment of the present invention. FIG. 2 is a side sectional view taken along line II-II of the wavelength selective switch shown in FIG. For easy understanding, FIGS. 1 and 2 show an XYZ orthogonal coordinate system. The wavelength selective switch 1 has a substantially rectangular parallelepiped shape having an upper surface and a bottom surface along the YZ plane and four side surfaces along the X-axis direction.

  As shown in FIGS. 1 and 2, the wavelength selective switch 1 includes an input / output optical system 18 including at least one input port and a plurality of output ports. As shown in FIG. 2, the input / output optical system 18 includes, for example, one input port 11 and four output ports 12a to 12d. Light L1 including a plurality of wavelength components is input to the input port 11 from the outside of the wavelength selective switch 1. The light L1 is signal light used for wavelength multiplexed optical communication, for example. The wavelength selective switch 1 splits the light L1 input to the input port 11 for each wavelength component, and outputs each wavelength component from each of the output ports 12a to 12d. In FIG. 1, three wavelength components L21, L22, and L23 and four output ports 12a to 12d are illustrated as an example. Each of the three wavelength components L21, L22, and L23 is output from each of the three output ports 12b, 12c, and 12d among the four output ports 12a to 12d.

  The input port 11 and the output ports 12a to 12d are arranged in a line in the X-axis direction. This arrangement direction is the same as the light deflection direction by the light deflection element 17 described later. The input port 11 is preferably configured by an optical waveguide member such as an optical fiber 21 and a microlens 31 (see FIG. 3) that collimates the light L1 input from the optical fiber 21. Each of the plurality of output ports 12a to 12d couples, for example, optical waveguide members such as optical fibers 22a to 22d, light L21 to L23 deflected by the optical deflection element 17, and the like to the end faces of the optical fibers 22a to 22d. It is comprised by the microlenses 32a-32d (refer FIG. 3). In the present embodiment, the microlenses 31 and 32a to 32d are integrated as the collimator lens 13, but each may be a separate body.

  The wavelength selective switch 1 further includes an anamorphic optical system 14, a spectroscopic element 15, a condensing element 16, a light deflecting element 17, and a control unit 20.

  The anamorphic optical system 14 receives the light L <b> 1 through the collimator lens 13. The anamorphic optical system 14 includes, for example, prisms 14a and 14b. The anamorphic optical system 14 converts the light L1 so that a cross-sectional shape perpendicular to the optical axis of the light L1 becomes an elliptical shape extending in the Y-axis direction. The beam shape of the light output from the anamorphic optical system 14 is such that the width of the light L1 is increased so that the width of the light L1 is increased in the Y-axis direction. Is an elliptical shape extending in the Y-axis direction. The anamorphic optical system 14 only needs to convert the cross section of the output light into an elliptical shape that is flat in the Y direction. In other words, the light may be reduced in the X direction so that the magnification in the Y direction is larger than the magnification in the X direction. Such an anamorphic optical system 14 includes, in addition to an optical system including a pair of prisms, an optical component having a refractive power in the X direction or the Y direction (for example, a cylindrical lens or a cylindrical mirror) alone or in combination. It may be configured.

  The spectroscopic element 15 splits the light L1 input from the input port 11 and having the beam shape converted by the anamorphic optical system 14 into the respective wavelength components L21 to L23. The spectroscopic element 15 of the present embodiment receives the light L1 via the collimator lens 13 and the anamorphic optical system 14. The spectroscopic element 15 is configured by, for example, a plate-like member having a diffraction grating formed on the surface. The wavelength components L21 to L23 of the light L1 split by the spectroscopic element 15 travel in different optical axis directions according to the wavelengths. In the present embodiment, the wavelength components L21 to L23 are dispersed in the above-described spectral direction (Y-axis direction).

  The condensing element 16 (condensing optical system) is disposed on the optical path between the spectroscopic element 15 and the light deflection element 17, and optically connects the spectroscopic element 15 and the light deflection element 17. The condensing element 16 is composed of, for example, a condensing lens, and condenses the wavelength components L21 to L23 that have passed through the spectroscopic element 15 toward the light deflection element 17. That is, the condensing element 16 couples each of the wavelength components L21 to L23 dispersed by the spectroscopic element 15 to the light deflecting element 17. At this time, the light expanded at a predetermined magnification in the Y direction in the anamorphic optical system 14 is reduced in the Y direction at the magnification in the light collecting element 16 (or in the X direction in the anamorphic optical system 14). The light reduced at the predetermined magnification is expanded in the X direction by the magnification at the light condensing element 16), so that the X direction magnification is larger than the Y direction magnification at the light deflection element 17. ing. The condensing element 16 collimates the wavelength components L21 to L23 deflected by the light deflecting element 17 toward the spectroscopic element 15.

  The optical deflecting element 17 is preferably composed of, for example, a MEMS mirror, receives each of the wavelength components L21 to L23 input from the input port 11 and dispersed by the spectroscopic element 15, and outputs the respective wavelength components L21 to L23 at a predetermined variable angle. As the light deflection element 17, in addition to a MEMS mirror, a reflection type liquid crystal element such as LCOS (Liquid Crystal on Silicon), a transmission type liquid crystal element, DMD (Digital Mirror Device), or DLP (Digital Light Processing) is applied. An element whose deflection angle is controlled by a voltage to be applied may be used.

  The MEMS mirror is a plurality of minute light reflecting surfaces manufactured by micromachine technology. The plurality of light reflecting surfaces are elastically supported, and are configured so that the angles thereof can be individually changed according to the magnitude of a control voltage applied to an actuator provided in each of the light reflecting surfaces. The light reflecting surfaces corresponding to the respective wavelength components are arranged in an array along the Y-axis direction. Each MEMS mirror rotates around an axis in the Y-axis direction, for example, and the deflection angle is controlled by the control unit 20 for each light of each wavelength component. The light reflected by the MEMS mirror passes through the condensing element 16, passes through the spectroscopic element 15, and is coupled to any one of the predetermined output ports 12 a to 12 d.

  FIG. 10 shows a case where LCOS is used as the light deflection element 17. The LCOS 90 includes a pixel electrode group 92 that is a reflective layer, a liquid crystal layer 93 that is a deflection layer, an alignment film 94, a transparent electrode 95, and a cover glass 96 on a silicon substrate 91 on which a drive circuit is formed. Consists of. An alignment film may also be provided between the pixel electrode group 92 and the liquid crystal layer 93 as necessary. The pixel electrode group 92 is configured so that a large number of pixels arranged in a predetermined direction correspond to light of a predetermined wavelength component, and periodically applying different voltages from each pixel electrode to the liquid crystal layer. As shown in FIG. 4, a step-like phase shift function is provided, and a change in the refractive index having a saw shape as a whole can be realized. By repeating this change periodically, a function equivalent to a blazed diffraction grating is realized. Thus, a multilevel optical phased array can be realized by changing the refractive index, and the reflection direction can be made different by a diffraction phenomenon. By adjusting the voltage applied to the pixel electrode group and appropriately selecting this phase shift function, the refraction angle of incident light can be changed in different directions for each wavelength, so the diffraction angle of each wavelength component can be changed. It can control independently and the input light of a specific wavelength can be reflected in a desired direction.

  The control unit 20 controls the angle of light deflected by the light deflection element 17, that is, the deflection angle. The control unit 20 controls the wavelength components L21 to L23 deflected in the X-axis direction by the light deflecting element 17 to the predetermined output ports 12b to 12d corresponding to the wavelength components L21 to L23, respectively, via the condensing element 16. The deflection angle of the optical deflecting element 17 is controlled so that they are coupled. The control unit 20 controls the threshold value of the optical coupling efficiency of the predetermined wavelength components L21 to L23 to the predetermined output ports 12b to 12d by controlling the deflection angle. It is preferable that the maximum value in the threshold value of the optical coupling efficiency in the predetermined output ports 12b to 12d is set so that the leakage light to the output port adjacent to the certain output port is sufficiently reduced.

  Here, a method for setting the maximum value of the threshold value of the optical coupling efficiency at the coupling destination port so that the leakage light to the adjacent port is sufficiently reduced by the deflection angle control by the control unit 20 will be described with reference to FIGS. The description will be given with reference. Note that, in FIG. 3, the main parts are emphasized for easy understanding of the present embodiment. The same applies to FIGS.

  As shown in FIG. 3, in this embodiment, as an example, a case will be described in which the output port 12c including the lens 32c is a coupling destination port, and the output ports 12b and 12d including the lenses 32b and 32d are adjacent ports. . In this case, the interval between the centers of the output ports 12b and 12c (hereinafter referred to as “pitch”) and the pitch of the output ports 12c and 12d are unequal, and the output port 12d is the output port 12c that is the coupling destination port. The closest port to In some cases, part of the light (wavelength component L22) input to the output port 12c, which is the coupling destination port, leaks to the closest port 12d.

  This state is shown in FIG. 4 as an example. FIG. 4 illustrates a case where the horizontal axis is the port arrangement direction (X direction), the connection destination port 12c is arranged at the coordinate 0, and the nearest port 12d is arranged at the coordinate 1.2. In FIG. 4, the vertical axis indicates the light intensity (dB), and the intensity distribution in the X direction of the wavelength component L22 coupled to the coupling destination port 12c. In FIG. 4, the light intensity distribution of the wavelength component L22 when the optical axis shift is not performed on the coupling destination port 12c (conventional) is indicated by the dotted line, and the light of the wavelength component L22 when the optical axis shift is performed (this embodiment). The intensity distribution is indicated by a dashed line.

  As shown in FIG. 4, by using the light intensity distribution of the wavelength component L22 when the optical axis shift is not performed, the optical axis shift is performed by referring to the light intensity of the wavelength component L22 corresponding to the predetermined coordinate in the X direction. In this case, the light intensity at which the wavelength component L22 is coupled to the coupling destination port 12c can be obtained. Then, referring to the light intensity of the wavelength component L22 at the coordinates where the nearest port 12d is located using the light intensity distribution of the wavelength component L22 when performing the optical axis shift, the wavelength component L22 when performing the optical axis shift. Can be determined as the light intensity coupled (leaked) to the nearest port 12d. Therefore, by determining the ratio of the light intensity of the wavelength component L22 at the predetermined position in the X direction to the maximum light intensity of the wavelength component L22, the coupling destination when the optical axis of the wavelength component L22 is positioned at the predetermined position in the X direction. The optical coupling efficiency of the wavelength component L22 for the port 12c and the nearest port 12d can be obtained.

  Such threshold setting of the optical coupling efficiency, particularly the threshold value of the intensity of light coupled to the coupling destination port 12c, is set in a range where the optical axis of the light is positioned when coupling the light to the coupling destination port 12c (control use). This is done by setting the range. Since the optical axis shift is not performed in the conventional setting of the light intensity threshold, the wavelength at which the light intensity threshold is coupled to the coupling destination port 12c, as shown by “control use range (conventional)” in FIG. The range in which the optical axis can be positioned was set so as to be in the control usage range of 0 dB to −15 dB including the parabolic peak (light intensity 0 dB) indicated by the component L22. That is, in the conventional threshold setting, a range in which the optical axis can be positioned is set so that the maximum value of the light intensity threshold includes a value (light intensity 0 dB) in which the optical coupling at the coupling destination port 12c is in an optimal coupling state. Was.

  On the other hand, in the setting of the threshold value of the light intensity in the present embodiment, the output port 12c is shifted by, for example, 0.2 mm in the direction away from the closest port 12d (left side in the figure) of the optical axis of the light input to the coupling destination port 12c. The lens 32c is coupled. This is because the control unit 20 controls the deflection angle of light in the light deflecting element 17 so that the optical axis of the wavelength component L22 coupled to the coupling destination port 12c and the optical axis of the coupling destination port 12c are shifted from each other. Can be controlled. Specifically, for example, as shown in FIG. 3, the control unit 20 moves toward the output port 12 b side away from the closest output port 12 d along the virtual straight line D1 connecting the output port 12 c and the output port 12 d. The deflection angle is controlled so as to shift the optical axis of the wavelength component L22.

  In order to perform such an optical axis shift, in the setting of the threshold value of the light intensity in the present embodiment, the threshold value of the light intensity is set to the wavelength component L22 as shown in “control use range (this embodiment)” in FIG. The range in which the optical axis can be positioned is set so as to be within the control usage range of -0.2 dB to -15.2 dB without including the parabolic peak indicated by. The maximum value -0.2 dB in the threshold value of the light intensity is the same as the wavelength component L22 when the optical axis of the wavelength component L22 that is coupled to the coupling destination port 12c by shifting the optical axis of the light is not shifted. The light intensity corresponding to the intersected value. Further, the lower limit value of the light intensity threshold value of -15.2 dB is set so that the upper limit (maximum value) is 0.2 dB, which is reduced from the optimum coupling state (0 dB), and the range of the control use range becomes the same as the conventional range. This is a value reduced with respect to the lower limit value of the conventional control use range. Thus, in the present embodiment, the maximum value of the light intensity threshold value does not include a value (light intensity 0 dB) at which the optical coupling at the coupling destination port 12c is in the optimum coupling state, that is, the optimum coupling state. The range in which the optical axis can be positioned is set differently.

  As described above, the light intensity in the X direction of the wavelength component L22 when the optical axis shift is performed and when the optical axis shift is not performed both changes in a quadratic function shape (parabolic shape) depending on the position coordinates in the X direction. Therefore, the intensity of light decreases with a steep inclination as it goes to both sides in the X direction with the parabolic peak indicated by the wavelength component L22 as the center. In the example of the present embodiment, the light intensity is decreased by −0.2 dB when the optical axis shift is performed at the connection destination port 12c (coordinate 0) as compared with the case where the optical axis shift is not performed. In the port 12d (coordinate 1.2), the light intensity −23 dB when the optical axis shift is not performed can be significantly reduced to the light intensity −32 dB by performing the optical axis shift. That is, by the above-described threshold control of the light intensity, the decrease amount of the light intensity leaking to the nearest port 12d can be greatly increased with respect to the decrease amount of the light intensity coupled to the coupling destination port 12c. As a result, according to the present embodiment, for example, when the practical target value of the intensity of leaked light is −30 dB, the amount of leaked light has a practical problem with the above-described method for setting the maximum value of the threshold value of light intensity. It is possible to reduce the value to less than the value with no.

  Even if the optical axis of the light L22 incident on the coupling destination port 12c is shifted from the predetermined port position in the optimum coupling state as described above, as described above, the wavelength component L22 input to the coupling destination port 12c. The light intensity threshold value is slightly changed from the conventional control use range “0 dB to 15 dB” to the control use range “−0.2 dB to −15.2 dB”. For this reason, since the setting of the control use range in which the optical axis of the light is positioned can be performed in the same manner as in the prior art, the coupling efficiency of the light L22 incident on the coupling destination port 12c is not a problem in practice.

  In this way, the control unit 20 sets the maximum value different from the optimum coupling state when controlling the threshold value of the optical coupling efficiency to the predetermined output port 12c, thereby inputting the threshold value to the predetermined output port 12c. The amount of attenuation of light input to the adjacent port 12d can be made larger than the amount of attenuation with respect to the optimal coupling state of the light to be performed. For this reason, it is possible to reduce the amount of leakage light with respect to the port 12d other than the output port 12c to be combined. In addition, since the amount of light leaked from the light (wavelength component L22) input to the adjacent port 12d or the like can be efficiently reduced, the interval between the output ports 12a to 12d can be shortened as compared with the prior art. It is also possible to further reduce the size.

  Further, in the wavelength selective switch 1, the control unit 20 sets the deflection angle so that the optical axis of the wavelength component L22 coupled to the lens 32c and the optical axis of the lens 32 are shifted from each other, so that the threshold of optical coupling efficiency is set. Further, the deflection angle of the wavelength component L22 is controlled along an imaginary straight line D1 connecting the output port 12c and the adjacent output port 12d. For this reason, in the wavelength selective switch 1 in which the ports 12a to 12d are uniaxially arranged, it is possible to reduce the amount of leakage light with respect to the ports 12d other than the output port 12c that is the coupling destination.

  In the wavelength selective switch 1, the control unit 20 controls the deflection angle so that the predetermined wavelength component L22 is separated from the output port 12d closest to the output port 12c. For this reason, it becomes possible to effectively reduce the amount of light leaked to the nearest output port 12d with the largest amount of light leaked.

  In the case of the port arrangement arranged at unequal pitches as described above, the shift amount of the optical axis is controlled on the side where the pitch interval is wide, while the side where the pitch interval is narrow is provided to reduce the size of the entire port. Therefore, in the wavelength selective switch including ports arranged at unequal pitches, the amount of light leaked to the nearest port can be reduced, and the wavelength selective switch can be further miniaturized.

  Although one embodiment of the wavelength selective switch according to the present invention has been described above, the present invention is not necessarily limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the case where the output port 12c is the coupling destination port has been described as an example. However, the same attenuation control may be applied even when the other output ports 12a, 12b, and 12d are the coupling destination ports. it can.

  In the above embodiment, the case where the pitches of the output ports 12a to 12d are unequal has been described as an example. However, as shown in FIG. The light leaked from the port can be attenuated. In this case, for example, the control unit 20 sets the deflection angle so that the optical axis of the wavelength component L22 coupled to the lens 32c and the optical axis of the lens 32 are shifted from each other, thereby setting the threshold of the optical coupling efficiency. A maximum value is set, and the optical axis of the predetermined wavelength component L22 is shifted along a straight line D2 orthogonal to a virtual straight line D1 connecting the output port 12c and the output ports 12b and 12d adjacent to the output port 12c. The deflection angle of the wavelength component L22 may be controlled. As a result, the amount of light leaked to the plurality of ports 12b and 12d adjacent to the output port 12c to be combined can be reduced.

  In the above-described case, the control unit 20 indicates that the leakage light amounts of the different wavelength components L21 and L23 input to the two output ports 12b and 12d adjacent to the predetermined output port 12c are as shown in FIG. The deflection angle of the wavelength component L22 may be controlled so that the optical axis of the predetermined wavelength component L22 is shifted so that optical coupling is performed at a position smaller than and equal to the predetermined target value (−30 dB). In this case, for example, if the ports 12b to 12d are arranged at equal intervals, the light coupling efficiency is monitored by monitoring the amount of light leaked from the two ports 12b and 12d adjacent to the output port 12c to be coupled. It can be easily adjusted to be the maximum value in the threshold value.

  In the above embodiment, the polarization angle is controlled so as to shift the optical axis of the predetermined wavelength component L22 along the virtual straight line D1 connecting the output ports 12c and 12d. However, as shown in FIG. 20 controls the deflection angle of the predetermined wavelength component L22 so that optical coupling is performed on a line having the same distance d from the two output ports 12b and 12d adjacent to the predetermined output port 12c among the plurality of output ports 12b to 12d. May be. In this case, the amount of light leaked to the ports 12b and 12d adjacent to each output port 12c to be combined can be minimized.

  In the above embodiment, the case where the input / output ports 11 and 12a to 12d are arranged in a line in a one-dimensional manner has been described as an example. However, as shown in FIG. 8, there are two input / output ports 11 and 12a to 12i. In the wavelength selective switch including the input / output optical system 18a arranged in a dimension, the above-described attenuation control may be applied. As an attenuation control method in this case, for example, as shown in FIG. 9, when the output port 12c is a connection destination port and the output ports 12a, 12b, and 12d surrounding the output port 12c in a triangular shape are the adjacent ports, the control unit No. 20 also controls the deflection angle so that the optical axis of the predetermined wavelength component L22 is shifted in the direction of the outer center C of the triangle having the three output ports 12a, 12b, 12d adjacent to the predetermined output port 12c as vertices. Good. As a result, the amount of leaked light from the coupling destination port 12c can be attenuated in the adjacent ports 12a, 12b, and 12d described above.

  DESCRIPTION OF SYMBOLS 1 ... Wavelength selection switch, 11 ... Input port, 12a-12d ... Output port, 13 ... Collimator lens, 15 ... Spectral element, 16 ... Condensing element, 17 ... Light deflection element, 18 ... Input / output optical system, 20 ... Control Part, 21, 22a-22d ... optical fiber, 31, 32a-32d ... lens, L1 ... light, L21-L23 ... wavelength component.

Claims (7)

An input / output optical system including at least one input port and a plurality of output ports;
A spectroscopic element that splits the light input from the input port for each wavelength component and outputs the wavelength component;
An optical deflection element that deflects each wavelength component output from the spectroscopic element and sets a deflection angle so as to be coupled to the predetermined output port;
A condensing optical system for coupling the wavelength component output from the spectroscopic element to the light deflection element;
A control unit that controls a threshold of optical coupling efficiency of the predetermined wavelength component to the predetermined output port by controlling the deflection angle; and
The said control part is a wavelength selective switch which sets the maximum value in the said threshold value of the said optical coupling efficiency so that it may differ from an optimal coupling state. The output port includes an optical waveguide member and an optical coupling member that couples the wavelength component to an end surface of the optical waveguide member,
The control unit sets the maximum value by setting the deflection angle so that an optical axis of the wavelength component coupled to the optical coupling member and an optical axis of the optical coupling member are shifted from each other, Further, the deflection angle of the predetermined wavelength component is controlled along a virtual straight line connecting the predetermined output port and the output port adjacent to the predetermined output port among the other output ports.
The wavelength selective switch according to claim 1. The output port includes an optical waveguide member and an optical coupling member that couples the wavelength component to an end surface of the optical waveguide member,
The control unit sets the maximum value by setting the deflection angle so that an optical axis of the wavelength component coupled to the optical coupling member and an optical axis of the optical coupling member are shifted from each other, Further, the deflection angle of the predetermined wavelength component is set along a straight line perpendicular to a virtual straight line connecting the predetermined output port and the output port adjacent to the predetermined output port among the other output ports. Control,
The wavelength selective switch according to claim 1. The control unit controls the deflection angle of the predetermined wavelength component so as to optically couple on a line having the same distance from two output ports adjacent to the predetermined output port among the plurality of output ports. ,
The wavelength selective switch according to claim 2 or 3. The control unit sets the deflection angle of the predetermined wavelength component so that optical coupling is performed at a position where the leakage light amounts of the other wavelength components input to the two output ports adjacent to the predetermined output port are equal. Control,
The wavelength selective switch according to any one of claims 1 to 4. Each of the plurality of output ports is arranged two-dimensionally at each end face,
The control unit controls the deflection angle of the predetermined wavelength component in the outer-center direction of a triangle having apexes of the three adjacent output ports adjacent to the predetermined output port.
The wavelength selective switch according to any one of claims 1 to 5. The control unit controls the deflection angle so that the predetermined wavelength component is separated from the output port closest to the predetermined output port;
The wavelength selective switch according to any one of claims 1 to 6.