JP5861130B2 - Wavelength selective optical cross-connect equipment - Google Patents

Description

  The present invention relates to a wavelength selective optical cross-connect device having a plurality of input / output paths provided in an optical node corresponding to a branch point of an optical network in the optical communication field.

  Wavelength multiplexing optical communication technology is used in high-speed and large-capacity optical networks that support today's advanced information and communication society. In an optical node corresponding to a branch point of an optical network, introduction of a reconfigurable optical add drop multiplexer (ROADM) device having a reconfigurable add / drop function is being promoted. In order to realize a ROADM device, a wavelength selective optical cross-connect device that switches light of an arbitrary wavelength in an arbitrary direction has attracted attention. As the current wavelength selective optical cross-connect devices, as shown in Patent Documents 1 to 3, the number of input routes M is 1, the number of output routes N is 2 or more, or the number of input routes M is 2 or more, and the output routes. The number N is one. In order to realize a future large-capacity network, it is required to improve the node processing capacity. There are a plurality of input routes (M) and a plurality of output routes (N), and any number of wavelengths in the input route. There is a need for a wavelength-selective optical cross-connect device that can select and output the light to the output path.

  In the conventional method, as shown in Patent Documents 1 to 3, M 1 × N wavelength selective switches (also referred to as Wavelength Selective Switches, WSS) connected to the input path, and N outputs each of which are inputs. A wavelength-selective optical cross-connect device that performs M × N switching can be realized using a single M × 1 wavelength selective switch. FIG. 1 is a diagram showing an example of a wavelength selective optical cross-connect device when the number of input routes M is 4 and the number of output routes N is 6. In this figure, the wavelength selective optical cross-connect device has four 1 × 6 wavelength selective switches (WSS) 110-1 to 110-4 connected to input routes Rin1 to Rin4. The outputs of the wavelength selective switches 110-1 to 110-4 are input to six 4 × 1 wavelength selective switches 120-1 to 120-6, respectively, and the selected outputs are output from the output routes Rout1 to Rout6. . Thereby, a wavelength selective optical cross-connect device can be realized.

  However, this wavelength selective optical cross-connect device has to use (N + M) wavelength selective switches. Since the wavelength selective switch has a complicated structure, the harder it can be mounted on the optical transmission mounting board, the larger the device area and the higher the price of the device. Since the configuration of FIG. 1 uses a large number of wavelength selective switches, there are drawbacks in that the failure rate is high and the transmission reliability is low.

  Therefore, in order to realize a small wavelength selective optical cross-connect device with a small number of parts, Patent Documents 1 and 3 propose to use a plurality of wavelength selective switches using the tilt of a micro mirror (MEMS). doing.

  Patent Document 4 discloses a wavelength selective optical cross-connect device in which a wavelength selective switch using an LCOS (Liquid Crystal On Silicon) liquid crystal element is applied to optical communication.

JP 2008-147804 A JP 2008-160401 A JP 2009-33543 A USP 7,787,720

  However, in the conventional method, the sum of the number of input routes M and the number of output routes N, that is, M + N wavelength selective switches, is used. As the number of routes increases, the number of wavelength selective switches increases and the cost increases. The rate also increases and the transmission reliability decreases. Further, when mechanically driving and controlling a mirror such as a MEMS, there is a drawback that it is inherently vulnerable to disturbances such as vibration and impact.

  In addition, the LCOS element disclosed in Patent Document 4 occupies a large panel surface of the LCOS element with respect to one input beam, and thus cannot be applied to a large number of input beams.

  The present invention has been made paying attention to such conventional problems, and without using a large number of wavelength selective switches, MEMS, or other movable parts, is small, reduces the mounting area, and improves transmission reliability. An object of the present invention is to realize a wavelength-selective optical cross-connect device having M inputs and N outputs (M and N are natural numbers of 2 or more).

  In addition, there is a document in which a wavelength-selective optical cross-connect device itself having a plurality of inputs and outputs is called a wavelength-selective switch device.

  In order to solve this problem, in the wavelength selective optical cross-connect device of the present invention, wavelength-multiplexed optical signals of the first to M-th channels (M is a natural number of 2 or more) are added to M input paths, respectively. A wavelength-selective optical cross that outputs N wavelength-multiplexed optical signals (N is a natural number equal to or greater than 2) by selecting a signal of at least one wavelength from the input wavelength-multiplexed optical signals A connecting device that separates each incident light of the incident M channel according to the polarization component of the incident light into first and second light beams, and rotates the polarization direction of one of them to change the polarization direction. And a first polarization diversity unit that uses 2M light beams, and a 2M wavelength multiplexed light that has passed through the first polarization diversity unit is spatially dispersed in accordance with the respective wavelengths. Wavelength dispersive element and wave Is arranged at a position for receiving 2M input lights developed on the xy plane composed of the x-axis direction developed in accordance with the y-axis direction and the y-axis direction perpendicular to the x-axis direction, and arranged in a grid pattern on the xy plane. A first spatial modulation element having a pixel and changing a reflection direction for each wavelength of each channel by changing a refractive index characteristic of the pixel by changing a phase of a plurality of pixels continuous in the y-axis direction; Is arranged at a position to receive light applied with inputs from the 2N first spatial modulation elements developed in the xy plane composed of the x-axis direction developed according to the y-axis direction and the y-axis direction perpendicular thereto. , Having a large number of pixels arranged in a grid on the xy plane, and changing the phase of a plurality of pixels continuous in the y-axis direction to change the refractive index characteristics of the pixels and reflect each wavelength of each channel Second space that changes direction A tuning element, a wavelength synthesizing element that synthesizes 2N spatially dispersed wavelengths of light from the second spatial modulation element into 2N wavelength multiplexed light, and 2N reflections synthesized by the wavelength synthesizing element. A second polarization diversity unit that rotates one polarization direction of the light of the same channel of the light to combine the 2N channel light into the N channel, and the xy direction of the first and second spatial light modulators; A spatial modulation element driving unit that changes the phase characteristics for each wavelength by driving the electrodes of the arranged pixels and reflects light in a different direction for each wavelength.

  Here, the beam switching functions of the first and second spatial modulation elements may be realized by changing the refractive index of the liquid crystal in a triangular wave shape.

  Here, the first and second spatial modulation elements may be LCOS elements.

  Here, the first and second spatial modulation elements may be two-dimensional liquid crystal array elements.

  Here, the first and second spatial modulation elements may have a liquid crystal driving mode of VA.

Here, the first and second spatial modulation elements may use an IPS system as a liquid crystal driving mode.
Is.

  As described above in detail, according to the present invention, the M-channel input light is added to the wavelength dispersive element as 2M parallel light beams by the polarization diversity unit, and the wavelength is dispersed by the wavelength dispersive element. Input to the spatial modulation element. In the first spatial modulation element, incident light is reflected in different directions for each wavelength of the same channel and guided to the second spatial modulation element. The second spatial modulation element controls the reflection direction so that light of a plurality of wavelengths in the same channel is in the same direction, passes through the second polarization diversity unit, becomes an N-channel output beam, and combines the wavelengths. Is output. Therefore, a cross-connect device can be realized by moving a plurality of input signals in each wavelength band to an arbitrary position of an arbitrary output port. In this case, by using the first and second spatial modulation elements, a flexible optical network can be formed without being affected by vibration or impact. Further, the wavelength band can be arbitrarily changed, and an effect that a highly flexible cross-connect device can be realized is obtained.

FIG. 1 is a block diagram showing an example of a conventional wavelength selective optical cross-connect device having four input routes and six output routes. FIG. 2 is a block diagram showing an example of a wavelength selective optical cross-connect device according to the first embodiment of the present invention. FIG. 3 is a perspective view showing the configuration of the main part of the wavelength selective optical cross-connect device according to the first embodiment of the present invention. FIG. 4A is a diagram showing an optical arrangement of the wavelength selective optical cross-connect device according to the second embodiment of the present invention viewed from the y-axis direction. FIG. 4B is a diagram illustrating an optical arrangement of two LCOS elements according to the second embodiment. FIG. 5A is a diagram showing an LCOS element used in the wavelength selector according to the present embodiment. FIG. 5B is a diagram showing the alignment state in the liquid crystal when the voltage of the liquid crystal material in the vertical alignment (VA) mode of the LCOS element used in this embodiment is not applied. FIG. 5C is a diagram showing the alignment state in the liquid crystal when a voltage in the vertical alignment mode of the LCOS element used in this embodiment is applied. FIG. 6A is a diagram showing a front surface and a light receiving region of the LCOS element 38 used in the present embodiment. FIG. 6B is an enlarged view showing details of the light receiving region R1 of the LCOS element 38. FIG. FIG. 7 is a diagram showing a light receiving region of the LCOS element 40 according to the second embodiment of the present invention. FIG. 8 is a graph showing changes in the phase angle in the y-axis direction of the LCOS element according to the second embodiment of the present invention and the conventional LCOS element. FIG. 9 is a diagram showing an optical arrangement of the wavelength selective optical cross-connect device according to the third embodiment of the present invention viewed from the y-axis direction.

(First embodiment)
FIG. 2 is a configuration diagram of a wavelength selective optical cross-connect device 1A according to the basic configuration of the present invention, and FIG. 3 is a perspective view showing its main part. The wavelength selective optical cross-connect device 1A has M (M is a natural number of 2 or more) input routes Rin1 to RinM and N (N is a natural number of 2 or more) output routes Rout1 to RoutN. Here, the optical signal of the first channel input to the input route Rin1 is a wavelength multiplexed optical signal (hereinafter referred to as a WDM signal) in which optical signals of λ ₁₁ to λ _L1 (L is a natural number of 2 or more) are multiplexed. To do. Similarly, the optical signal of the second channel input to the input route Rin2 is also a WDM signal in which optical signals of wavelengths λ ₁₂ to λ _L2 are multiplexed. In general, the input route Rin (j
The WDM signal of the jth channel input to) is a WDM signal (j = 1 to M) in which optical signals of wavelengths λ _{1j to} λ _Lj are multiplexed. Here, the same first suffix (1-L) represents the same wavelength, and the second suffix (1-M) represents a channel. The M-channel WDM signal is input to a collimating lens array including collimating lenses 12-1 to 12-M via optical fibers 11-1 to 11-M. A polarization diversity unit 13 is provided on the output side of each of the collimating lenses 12-1 to 12-M. The polarization diversity unit 13 is one of a polarization beam splitter that separates the wavelength multiplexed light at each input port into first and second light beams of s-polarized component and p-polarized component, and a separated light beam at each input port. It has a wave plate for converting one polarization direction into the other polarization direction, and the WDM light of each channel is made into two parallel light beams. Two light beams of each channel are given to the wavelength dispersion element 14. The wavelength dispersion element 14 disperses light in different directions depending on the wavelength of 2M input light from the polarization diversity unit 13 and can be realized by a diffraction grating, for example. The output from the wavelength dispersion element 14 is guided to the first spatial modulation element 15 through a condensing means or the like. The first spatial modulation element 15 receives the dispersed light of each channel and each wavelength and outputs it to any channel from 1 to N of the second spatial modulation element 16 for each channel and each wavelength. It is an element that changes its direction and reflects. The second spatial modulation element 16 performs direction conversion for outputting the reflected lights from different directions dispersed in the two wavelengths for each of the first to N-th channels in a predetermined direction. It is an element. A controller 17 is connected to the first and second spatial modulation elements 15 and 16. Then, the output from the second spatial modulation element 16 is given to the wavelength synthesizing element 18 through an appropriate condensing element. The wavelength synthesizer 18 synthesizes 2N different wavelength components into one wavelength component, condenses them in the same direction and outputs them, and is realized by a diffraction grating, for example. A polarization diversity unit 19 is provided on the output side of the wavelength combining element 18. The polarization diversity unit 19 is configured to rotate one polarization direction of the light of the same channel among the 2N reflected lights synthesized by the wavelength synthesizing element and synthesize the 2N channel light into the N channel, respectively. Collimating lenses 20-1 to 20 -N and output fibers 21-1 to 21 -N are connected to the output side of the polarization diversity unit 19. These have a symmetric structure with the input optical fibers 11-1 to 11 -M, the collimating lens arrays 12-1 to 12 -M, and the polarization diversity unit 13.

  Next, the spatial modulation elements 15 and 16 will be described. In the first embodiment, when incident light is dispersed on the xz plane according to the wavelength and is incident on the spatial modulation element 15 as band-shaped light, the incident areas are rectangular areas R1 to RM shown in FIG. Suppose that In the wavelength selective optical switch device according to the first embodiment, the direction of reflection is selected for each wavelength of each channel, and is incident on the same wavelength band portion of any one of R1 to RN of the spatial modulation element 16. To do. The second spatial modulation element 16 receives light from different directions for each wavelength band of each channel, and reflects the light in the same direction to output it to the wavelength synthesis element 18. In this way, light having an arbitrary wavelength can be selected by controlling the reflection directions of the first and second spatial modulation elements 15 and 16. The controller 17 determines the reflection direction of light on the xy plane according to the selected wavelength. The controller 17 constitutes a spatial modulation element driving unit that controls the characteristics of the pixels at predetermined positions in the x-axis and y-axis directions by driving the electrodes of the pixels arranged in the xy direction of the spatial modulation elements 15 and 16. ing. In FIG. 3, two light beams of the same channel are described together, but actually, the reflection directions of the two parallel light beams are simultaneously switched and switched.

(Second Embodiment)
Next, a more specific embodiment of the present invention will be described. FIG. 4A is a diagram illustrating a configuration of a main part of an 8-input 8-output (M = N = 8) wavelength selective optical cross-connect device 1B according to the second embodiment. In the drawing, eight optical fibers 31 are arranged in parallel in the y-axis direction, and a collimating lens of a collimating lens array 32 is connected to each optical fiber 31. A polarization diversity unit 33 is disposed on the output side, and a mirror 34 is provided on the optical axis. A diffraction grating 35, which is a wavelength dispersion element, is provided at a position where the light reflected by the mirror 34 is received. The diffraction grating 35 has the same function as the wavelength dispersion element 14 of the first embodiment, and is connected to the first LCOS element 38 via the y-axis direction condensing lens 36 and the x-axis direction condensing lens 37. Given. The LCOS element 38 corresponds to the first spatial modulation element 15 of the first embodiment. A second LCOS element 40 is provided via an x-axis direction condensing lens 39 at a position facing the LCOS element 38. The LCOS element 40 corresponds to the second spatial modulation element 16 of the first embodiment. The light reflected by the LCOS element 40 is given to a diffraction grating 43 which is a wavelength synthesizing element via an x-axis direction condensing lens 41 and a y-axis direction condensing lens 42. The diffraction grating 43 synthesizes wavelength-dispersed light in each direction into 16 light beams, and the output is given to the polarization diversity unit 45 and the collimating lens array 46 via the mirror 44. An output optical fiber 47 is connected to the collimating lens array 46. The polarization diversity units 33 and 45 correspond to the polarization diversity units 13 and 19 of the first embodiment.

  Next, a detailed configuration of the LCOS elements 38 and 40 used in the wavelength selective optical cross-connect device 1B according to the second embodiment will be described. Since the LCOS elements 38 and 40 have a liquid crystal modulation driver built in the back of each pixel, the number of pixels can be increased, and the LCOS elements 38 and 40 can be composed of a large number of lattice-like pixels. FIG. 5A is a schematic diagram showing the LCOS elements 38 and 40, and an alignment layer 55 including an AR layer 51, a transparent common electrode 52, a liquid crystal 53, and a large number of back reflection electrodes 54 along the z axis from the light incident surface, A silicon layer 56 is laminated.

FIG. 6A is a front view of the LCOS element 38 according to the second embodiment. Here, assuming that the wavelength dispersion direction is the x-axis direction shown in FIG. 6A, a large number of pixels arranged in the y-axis direction correspond to the respective wavelengths. Light beams are incident on the LCOS element 38 at different positions for each channel and for each wavelength. That is, the light applied to the incident region Rj is light obtained by developing WDM light on the xy plane according to the wavelength band λ _ij (i = 1 to L, j = 1 to M). In the second embodiment, the number of input ports M and the number of output ports N are both 8. At each input port, two beams are dispersed for each wavelength by the diffraction grating 35 and applied to the LCOS element 38. For example, incident light of s-polarized light and p-polarized light at the first port is wavelength-dispersed and added to the region R1 shown in FIG. 6A. Similarly, the incident light of the s-polarized light and the p-polarized light from the second port to the eighth port is wavelength-dispersed and added to the regions R2 to R8, respectively. FIG. 6B shows the region R1 in an enlarged manner. The wavelength dispersion of the s-polarized component at the upper part and the p-polarized component at the lower part thereof, and light of wavelengths λ _{11 to} λ _L1 respectively enter different positions. Here, the LCOS element 38 uses an element with a diagonal of 0.7 inches (16.127 × 9.071 mm), and is an element in which 1920 elements in the x direction and 1080 pixels in the y direction are arranged in a grid pattern. . At this time, 135 pixels (pxl) correspond to the y-axis direction for λ _ij (i = 1 to L, j = 1 to 8) in which the two input lights at the port positions in the y-axis direction are wavelength-dispersed. . Furthermore, as shown in FIG. 6B, 67 pixels correspond to the light beams of the respective polarization components. The setting unit 57 and the driver 58 constitute a spatial modulation element driving unit, which controls the emission direction of incident light.

  Since the LCOS element 40 also has an output port number N of 8, the light receiving regions R1 to R8 are set as shown in FIG. Also in this case, the emission direction of the incident light is controlled by the setting unit 57 and the driver 58.

  Next, the beam polarization method of the LCOS element will be described. As a method for controlling the refractive index distribution of a conventional crystal element, as shown in Patent Document 4, an optical phase array (Optical phase array: OPA method) is known. In this method, as indicated by reference symbol A in FIG. 8, a refractive index distribution is formed periodically like a sawtooth wave with a phase modulation amount of 2π rad, and beam switching polarization is performed by a diffraction effect. In the OPA system, in order to obtain a high beam diffraction efficiency, it is necessary to increase the beam diameter and repeat the sawtooth wave refractive index distribution.

  In contrast, in this embodiment, a liquid crystal beam deflection method (hereinafter referred to as an LCBD method) is used. In the LCBD method, beam refraction can be performed in a small space by increasing the amount of phase modulation as indicated by symbol B in FIG. Therefore, as shown in FIG. 6A and FIG. 7, even if the surface of one LCOS element is divided into a plurality of regions R1 to R8 and each region is irradiated with a light beam, the light in each direction is different for each wavelength. Can be reflected. Unlike the OPA method, the LCBD method does not form a sawtooth-like phase change on the LCOS surface, and therefore has no flyback effect and less high-order diffracted light. In the case of using the LCBD method, it is necessary to increase the thickness of the liquid crystal cell to 5 to 200 μm as compared with the liquid crystal cell thickness (1 to 10 μm) with the OPA method in order to obtain a necessary refractive index gradient. .

  In the second embodiment, when switching light having a certain wavelength received in the region R1 shown in FIG. 6A toward the region R8 of the second LCOS element 40, for example, the maximum deflection angle is required. . In the second embodiment, as shown in FIG. 4B, the first LCOS element 38 and the second LCOS element 40 have a distance of 100 mm through the lens. In this case, a deflection angle of about 4.6 ° is required.

The LCOS elements 38 and 40 according to the second embodiment use a vertical alignment (VA) type liquid crystal material having a refractive index anisotropy of 0.2. Thus, the vertically incident light is diffracted and reflected by an angle θ. The angle θ is expressed by the following equation when the crystal cell thickness is d.
θ = 2d · (dn / dy)
Here, when the crystal cell thickness d is 108 μm, the beam deflection angle θ is about 0.09 (rad) and the maximum angle is 4.9 °, and the light received in the region R1 is the region of the second LCOS element 40. It is possible to obtain a deflection angle that exceeds the beam deflection angle of 4.6 ° required when switching toward R8.

Therefore, by applying different voltages to a large number of pixels in the y-axis direction on which the light λ _ij having a certain wavelength of the LCOS element 38 is incident, a change in the refractive index represented by a triangular wave phase shift function as shown in FIG. Can be realized. Thus, the reflection direction can be varied by changing the refractive index. Here, by appropriately selecting the phase shift function, the refraction angle of the incident light can be changed in different directions for each wavelength, so that the LCOS elements 38 and 40 can be considered as variable characteristic diffraction gratings. . Therefore, by applying a voltage between the transparent electrode 52 and the back reflecting electrode 54, the diffraction angle of each wavelength component is controlled independently, and the input light of a specific wavelength is reflected in a desired direction, or other wavelength components of Light can be diffracted as unnecessary light and reflected in a direction not emitted.

Or switching This way for example the incident light lambda ₁₁ of LCOS device 38 shown in FIG. 6A to the position of the wavelength lambda ₁₈ area R8 of the second LCOS element 40 shown in FIG. 7, the incidence of lambda ₃₁ of LCOS element 38 Light can be incident on λ ₃₇ in the region R 7 of the LCOS element 40. However, it is assumed that the setting unit 57 controls the light receiving regions of the second LCOS element 40 in advance so that a plurality of lights having the same wavelength are not incident on the same position. The 16 incident lights having the same wavelength λ _{11 to} λ ₁₈ are incident on any position of λ _{11 to} λ ₁₈ in the second LCOS element, and are not incident on other regions. If it does so, it can control so that all the light which injected with the 2nd LCOS element may be reflected in the same direction, and it can synthesize | combine with the diffraction grating 44 and can convert it into 16 light beams.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 9 is a diagram showing a configuration of a main part of an 8-input 8-output (M = N = 8) wavelength selective optical cross-connect device 1C according to the third embodiment. In the drawing, eight optical fibers 61 are arranged in parallel in the y-axis direction, and a collimating lens of a collimating lens array 62 is connected to each optical fiber 61. A polarization diversity unit 63 is disposed on the output side, and a magnifying prism 64 is disposed on the optical axis. A diffraction grating 65 which is a wavelength dispersion element is provided at a position where the light magnified by the magnification prism 64 is received. The diffraction grating 65 has the same function as the wavelength dispersion element 14 of the first embodiment, and is given to the LCOS element 67 through the y-axis direction condensing lens 66. The LCOS element 67 corresponds to the first spatial modulation element 15 of the first embodiment. An LCOS element 69 is provided at a position facing the LCOS element 67 via x-axis direction condensing lenses 66 and 68. The LCOS element 69 corresponds to the second spatial modulation element 16 of the first embodiment. The light reflected by the LCOS element 69 is given to a diffraction grating 70 which is a wavelength synthesizing element via an x-axis direction condenser lens 68. The diffraction grating 70 synthesizes wavelength-dispersed light in each direction into 16 light beams, and the output is given to the polarization diversity unit 72 and the collimating lens array 73 via the magnifying prism 71. An output optical fiber 74 is connected to the collimating lens array 73. The polarization diversity units 63 and 72 correspond to the polarization diversity units 13 and 19 of the first embodiment.

  In this embodiment, 0.7 inch LCOS elements are used for the two LCOS elements 67 and 69 as in the second embodiment, and the resolution is 1920 × 1080 pixels. The interval between the two LCOS elements is 200 mm. In this embodiment, the liquid crystal driving mode uses an IPS (In-Plane Switching) mode having excellent wide viewing characteristics. In addition, since a liquid crystal material having a refractive index anisotropy of 0.2 is used and the LCOS interval is doubled here, the beam deflection angle is 2 as compared with the second embodiment even if the same LCOS element is used. A deflection angle of 3 ° is sufficient. Therefore, the thickness of the LCOS elements 67 and 69 can be halved of the LCOS elements 38 and 40 of the second embodiment, and the crystal cell thickness is 54 μm. This embodiment is also superior in mounting efficiency compared to the conventional example and can be arranged in a small size.

  In each of the above-described embodiments, two LCOS elements are used. However, the area of one LCOS element is divided into two to be the first and second areas, and the first area is defined by using an appropriate mirror. The first LCOS element and the second region can be used as the second LCOS element. In this way, a wavelength selective optical cross-connect device can be realized using one LCOS element.

  In the second and third embodiments, the LCOS elements 38, 40, 67, and 69 are described as the spatial modulation elements. As another example, a liquid crystal having a reflective two-dimensional electrode array that does not have an LCOS structure. An element can be used. In the case of the LCOS element, a liquid crystal driver is built in the back of the pixel, but in the two-dimensional electrode array liquid crystal element, a driver for liquid crystal modulation is provided outside the element. Other configurations are the same as those of the LCOS element, and deflection control by the LCBD method described above can be realized.

  In this embodiment, since a spatial modulation element having a large number of pixels in a lattice shape is used, the wavelength width of each channel band can be arbitrarily set. Therefore, if the width of a specific wavelength band is wide, the number of pixels in the x-axis direction in FIGS. 6A and 7 is increased, or if the wavelength band is narrow, the number of pixels in the x-axis direction is decreased. Pixels can be set as appropriate in accordance with the width of.

  In this embodiment, the WDM signal light is used as the input signal. However, the present invention can be applied not only to the WDM signal light but also to light on which many wavelengths are superimposed.

  The present invention can be suitably used as a wavelength-selective optical cross-connect device for an optical node that is provided at a branch point of an optical network and switches a large number of WDM lights for each wavelength.

1A, 1B, 1C Wavelength selective optical cross-connect device 12-1 to 12-M, 20-1 to 20-N Collimate lens 13, 19, 33, 45, 63, 72 Polarization diversity unit 26, 37, 39, 41 , 42, 66, 68 Lens 14 Wavelength dispersion element 15, 16 Spatial modulation element 17 Controller 18 Wavelength synthesis element 31, 48, 61, 74 Optical fiber 32, 47 Collimating lens array 35, 43, 65, 70 Diffraction grating 38, 40 , 67, 69 LCOS element 57 Setting section 58 Driver

Claims (6)

Wavelength multiplexed optical signals of the first to M-th channels (M is a natural number of 2 or more) are added to M input paths, and a signal of at least one wavelength is selected for each input wavelength multiplexed optical signal. N wavelength (N is a natural number greater than or equal to 2) wavelength-multiplexed optical signals, and output from N output paths;
Each of the incident light of the incident M channel is separated according to the polarization component of the incident light to form the first and second light beams, and the polarization direction is aligned by rotating one of the polarization directions. A first polarization diversity unit as a beam;
A first wavelength dispersion element that spatially disperses each of the 2M wavelength multiplexed lights that have passed through the first polarization diversity unit according to the wavelength;
A large number of 2M input lights developed on an xy plane composed of an x-axis direction developed according to the wavelength and a y-axis direction perpendicular to the x-axis direction are arranged in a grid pattern on the xy plane. A first spatial modulation element that changes the refractive index characteristic of the pixel by changing the phase of a plurality of pixels that are continuous in the y-axis direction and changes the reflection direction for each wavelength of each channel;
Arranged at a position to receive light applied with inputs from the 2N first spatial modulation elements developed in the xy plane composed of the x-axis direction developed according to the wavelength and the y-axis direction perpendicular thereto. A plurality of pixels arranged in a grid on the xy plane, and changing the phase of a plurality of pixels continuous in the y-axis direction to change the refractive index characteristics of the pixels for each wavelength of each channel. A second spatial modulation element that changes the reflection direction;
A wavelength combining element that combines 2N spatially dispersed wavelengths of light from the second spatial modulation element into 2N wavelength multiplexed light;
A second polarization diversity unit that rotates one polarization direction of the light of the same channel among the 2N reflected lights synthesized by the wavelength synthesizing element to synthesize the 2N channel light into the N channel, respectively;
Spatial modulation that changes the phase characteristic for each wavelength by driving the electrodes of each pixel arranged in the xy direction of the first and second spatial modulation elements and reflects light in a different direction for each wavelength A wavelength selective optical cross-connect device comprising: an element driving unit;   2. The wavelength selective optical cross-connect device according to claim 1, wherein the beam switching functions of the first and second spatial light modulators are realized by changing the refractive index of the liquid crystal in a triangular wave shape.   The wavelength selective optical cross-connect device according to claim 1, wherein the first and second spatial modulation elements are LCOS elements.   2. The wavelength selective optical cross-connect device according to claim 1, wherein the first and second spatial modulation elements are two-dimensional liquid crystal array elements.   4. The wavelength selective optical cross-connect device according to claim 3, wherein the first and second spatial modulation elements use a VA mode liquid crystal driving mode.   4. The wavelength selective optical cross-connect device according to claim 3, wherein the first and second spatial modulation elements have an IPS liquid crystal driving mode. 5.

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