Large-port-number matrix optical switch and optical communication equipment based on prism group

Abstract

The present application belongs to the field of optical fiber communication, and specifically discloses a large-port matrix optical switch and optical communication equipment based on a prism group. Through the present application, a prism group is respectively set in front of the first LCOS chip and the second LCOS chip. The prism group in front of the first LCOS chip applies additional deflection to the two beams of mutually parallel linear polarized light after polarization diversity of each port of the optical front end through refraction on the xz plane, thereby reducing the deflection angle requirement of the first LCOS chip. The prism group in front of the second LCOS chip applies additional deflection to the linear polarized light reflected by the concave reflector through refraction on the xz plane, so that it is corrected to be parallel to each other, thereby offsetting the additional deflection applied by the former, reducing the deflection angle requirement of the second LCOS chip, further increasing the diffraction efficiency, and reducing the loss of the matrix switch. In other words, when the diffraction deflection angle of the LCOS chip is constant, this optical design can realize a matrix switch with a larger number of ports.

Description

Technical Field

[0001] The present application belongs to the field of optical fiber communication, and more specifically, to a large-port matrix optical switch and optical communication equipment based on a prism group. Background Art

[0002] With the promotion and application of 5G communications and the development of mobile Internet, network traffic has grown rapidly. As one of the Internet infrastructures, data centers are becoming larger and larger and their business is becoming busier. After introducing fiber optic interconnection technology, data centers are introducing large-scale matrix optical switches (>100×100 ports) to improve access efficiency. It has a wide range of application needs in data centers and computing centers.

[0003] There are many technical solutions to realize large-scale matrix optical switches, but there are only three technical solutions with practical prospects: 1) DirectLight technology, which drives the optical fiber behind two microlens arrays through piezoelectric materials to realize optical path switching; 2) 3DMEMS technology, which realizes large-scale optical path switching through two MEMS micromirror arrays; 3) Liquid crystal on silicon (LCOS) technology, which realizes beam deflection and optical path switching through two pure phase-modulated LCOS chips. The first solution can realize a matrix switch with a large number of ports, but the drive is complex and the drive voltage is high; the second solution has the advantages of simple optical path and low loss, but the MEMS chip is expensive and has a low yield; the third solution, the LCOS chip that controls the beam deflection is a fully solid-state component, and there is no mechanical moving part in the entire matrix switch, so it has the advantage of high reliability. In addition, the LCOS chip is much cheaper than the piezoelectric driver in the first solution and the MEMS chip in the second solution, and the drive voltage is lower, and the drive design is simpler.

[0004] In the LCOS matrix optical switch, the LCOS chip deflects the light beam through the diffraction effect to achieve optical path switching between ports. The disadvantage of this solution is that the LCOS chip has a slightly smaller deflection angle for the light beam (increasing the deflection angle will reduce the diffraction efficiency and thus increase the loss), which limits the number of ports of the matrix optical switch. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of this application is to provide a large-port-count matrix optical switch and optical communication equipment based on a prism group, aiming to solve the problem that the existing LCOS chip has a slightly small deflection angle of the light beam, which restricts the number of ports of the matrix optical switch.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a large-port-count matrix optical switch based on a prism group, comprising an optical front end, a first prism group, a first LCOS chip, a concave reflector, a second prism group, a second LCOS chip and an optical back end arranged in sequence along a planar W-shaped optical path;

[0007] The first LCOS chip and the second LCOS chip are both arranged on the focal plane of the concave reflector, and the three together constitute a 2F optical system;

[0008] The first prism group and the second prism group have the same structure. The former applies additional deflection to two mutually parallel linear polarized light beams after polarization diversity at each port of the optical front end through refraction on the xz plane, and the latter applies additional deflection to the linear polarized light beams reflected by the concave reflector through refraction on the xz plane, so as to correct them to be mutually parallel.

[0009] Under the premise that no driving voltage is applied to the first LCOS chip and the second LCOS chip, two groups of parallel light beams generated by polarization diversity from each port of the optical front end are refracted by the first prism group, reflected by the first LCOS chip, reflected by the concave reflector and refracted by the second prism group in sequence, and then are incident on the center positions of the upper and lower halves of the second LCOS chip respectively.

[0010] Preferably, the distance between the first prism group and the first LCOS chip is in the range of [0, 1 mm], and the distance between the second prism group and the second LCOS chip is in the range of [0, 1 mm].

[0011] Preferably, in the large-port-count matrix optical switch, the first prism group, the first LCOS chip and the concave reflector need to simultaneously meet the following two conditions:

[0012]

[0013]

[0014] in, is the number of ports in the x direction of the optical front end, is the side length of the pixel area allocated to a single port on the first LCOS chip, is the length of the first LCOS chip, is the focal length of the concave reflector, is the angle between the incident light and the normal of the incident surface of the first prism group, is the angle between the outgoing light and the normal of the outgoing surface of the first prism group, is the refractive index of the first prism group.

[0015] Preferably, the first prism group is formed by gluing two identical quadrangular prisms together. When viewed from the side, the quadrangular prism is a right-angled trapezoid. The right-angled thick ends of the two quadrangular prisms are aligned, and the first prism group is in a roof shape.

[0016] Preferably, the first prism group is composed of two identical triangular prisms. When viewed from the side, the triangular prisms are right-angled triangles. The thin ends of the two triangular prisms are aligned, and the first prism group is V-shaped.

[0017] Preferably, the thickness of the thinnest part of the prism group is not less than 0.3 mm.

[0018] Preferably, the first prism group is a rectangle in a top view, the length of the rectangle is at least 2 mm greater than the length of the first LCOS chip, and the width of the rectangle is at least 2 mm greater than the width of the first LCOS chip.

[0019] Preferably, the optical front end comprises a two-dimensional collimator array, a polarization beam splitter prism, a compensation block and a half-wave plate; wherein,

[0020] The two-dimensional collimator array includes a plurality of ports, each port is used to transform a small spot divergent light beam at the output end of the optical fiber into a large spot collimated light beam, which enters the polarization beam splitter prism;

[0021] The polarization splitter prism is used to transmit p-waves and reflect s-waves, so that after polarization splitting, an incident beam of randomly polarized light is obtained into two beams of linear polarized light that are parallel to each other and have orthogonal polarization states. One of the beams of light passes through a compensation block to compensate for the optical path difference between the two beams of light, and after passing through a half-wave plate, the polarization state is rotated 90°. Finally, the two beams of light are parallel to each other and have the same polarization state, thus realizing polarization diversity.

[0022] Preferably, the maximum diffraction deflection angle in the x direction generated by the corresponding block on the first LCOS chip is , maximum diffraction deflection angle in the y direction ,in, is the focal length of the concave reflector, Indicates the number of ports in the x direction of the optical front end. Indicates the number of ports in the Y direction of the optical front end. is the side length of the pixel area allocated to a single port on the first LCOS chip, is the number of ports of the optical front end, is the size of the pixel area allocated to a single port on the first LCOS chip.

[0023] To achieve the above-mentioned objectives, in a second aspect, the present application provides an optical communication device, comprising a large-port-count matrix optical switch and a circuit control board as described in the first aspect; the circuit control board is used to provide a phase control signal for a first LCOS chip and a second LCOS chip in the large-port-count matrix optical switch.

[0024] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0025] The present application provides a large-port matrix optical switch and optical communication device based on a prism group, wherein a prism group is respectively arranged in front of a first LCOS chip and a second LCOS chip, and the prism group in front of the first LCOS chip applies additional deflection to two mutually parallel linear polarized lights after polarization diversity at each port of the optical front end through refraction on the xz plane, thereby reducing the deflection angle requirement of the first LCOS chip, and the prism group in front of the second LCOS chip applies additional deflection to the linear polarized lights reflected by the concave reflector through refraction on the xz plane, so that the linear polarized lights are corrected to be parallel to each other, thereby offsetting the additional deflection applied by the former, reducing the deflection angle requirement of the second LCOS chip, further increasing the diffraction efficiency, and reducing the loss of the matrix switch. In other words, when the diffraction deflection angle of the LCOS chip is constant, this optical design can realize a matrix switch with a larger number of ports. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a large-port-number matrix optical switch based on a prism group provided in an embodiment of the present application.

[0027] Figure 2 It is a schematic diagram of the optical front-end structure provided in an embodiment of the present application.

[0028] Figure 3 This is a diagram showing the correspondence between pixel partitions and ports on the LCOS chip provided in an embodiment of the present application.

[0029] Figure 4 This is a schematic diagram of the first prism group structure provided in an embodiment of the present application.

[0030] Figure 5 This is a schematic diagram of the second prism group structure provided in an embodiment of the present application.

[0031] Figure 6 This is a schematic diagram of light beam deflection by a first type of prism structure provided in an embodiment of the present application.

[0032] Figure 7 It is an equivalent optical path diagram of the 2F optical system provided in an embodiment of the present application, wherein (a) corresponds to no prism group, (b) corresponds to a prism group of the first structure being set in front of the LCOS chip, and (c) corresponds to a prism group of the second structure being set in front of the LCOS chip.

[0033] Figure 8 This is a comparison diagram of the light spot position on the second LCOS chip provided in an embodiment of the present application, (a) corresponds to no prism group, and (b) corresponds to a prism group set in front of the LCOS chip.

[0034] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0035] 1-optical front end, 2-first prism group, 3-first LCOS chip, 4-concave reflector, 5-second prism group, 6-second LCOS chip, 7-optical back end, 11-two-dimensional collimator array, 12-polarization beam splitter prism, 13-compensation block, 14-half-wave plate. DETAILED DESCRIPTION

[0036] For ease of understanding, the English abbreviations and related technical terms involved in the embodiments of the present application are explained and described below.

[0037] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0038] like Figure 1 As shown, the present application provides a large-port-count matrix optical switch based on a prism group, comprising an optical front end 1, a first prism group 2, a first LCOS chip 3, a concave reflector 4, a second prism group 5, a second LCOS chip 6, and an optical back end 7, which are sequentially arranged along the optical path. The first LCOS chip 3 and the second LCOS chip 6 are both arranged on the focal plane of the concave reflector 4, forming a 2F optical system and a W-shaped optical path.

[0039] The optical front end 1 and the optical back end 7 have the same structure. Each port of the former transforms the small spot divergent light beam of the input optical fiber into a large spot collimated light beam, and after polarization diversity, obtains two parallel linear polarized lights with the same polarization state, which are incident on the first prism group 2. Each port of the latter combines the two parallel linear polarized lights with the same polarization state output from the second LCOS chip 6 into one beam, and then couples it to the output optical fiber.

[0040] The first prism group 2 and the second prism group 5 have the same structure, and both have a wedge angle in the x direction ( Figure 6 In ), thereby generating refraction on the xz plane. The first prism group 2 applies additional deflection to the two mutually parallel linear polarized lights after polarization diversity at each port of the optical front end through refraction on the xz plane, thereby reducing the deflection angle requirement of the first LCOS chip 3; the second prism group 5 applies additional deflection to the linear polarized lights reflected by the concave reflector through refraction on the xz plane, so as to correct them to be parallel to each other, thereby offsetting the additional deflection applied by the former, and reducing the deflection angle requirement of the second LCOS chip 6.

[0041] The first LCOS chip 3 and the second LCOS chip 6 have the same structure, and are respectively used to change the diffraction deflection angle of the light beam by electrical control after applying a driving voltage, so as to realize the optical path switching between different ports.

[0042] Under the premise that no driving voltage is applied to the first LCOS chip 3 and the second LCOS chip 6, two groups of parallel light beams generated by polarization diversity from each port are refracted by the first prism group, reflected by the first LCOS chip, reflected by the concave reflector and refracted by the second prism group in sequence, and then incident on the center positions of the upper and lower halves of the second LCOS chip respectively.

[0043] Preferably, if Figure 2 As shown, the optical front end 1 includes a two-dimensional collimator array 11, a polarization beam splitter prism 12, a compensation block 13 and a half-wave plate 14; wherein,

[0044] The two-dimensional collimator array 11 includes a plurality of ( ) ports, each port is used to transform the small spot divergent beam at the output end of the optical fiber into a large spot collimated beam, which enters the polarization beam splitter prism;

[0045] The polarization splitter prism 12 is used to transmit p-waves and reflect s-waves, so that after polarization splitting, an incident beam of randomly polarized light is obtained into two beams of linear polarized light that are parallel to each other and have orthogonal polarization states. One of the beams of light passes through the compensation block 13 to compensate for the optical path difference between the two beams of light, and the polarization state is rotated 90° after passing through the half-wave plate 14. Finally, the two beams of light are parallel to each other and have the same polarization state, thereby realizing polarization diversity.

[0046] Preferably, the polarization beam splitter prism 12 is a glued prism consisting of a triangular prism and a rhombus prism, and a polarization beam splitter film is coated on the glued surface of the two, which can transmit p-waves (polarized light with the light vector parallel to the paper surface) and reflect s-waves (polarized light with the light vector perpendicular to the paper surface). Since the optical path in the rhombus prism is larger than that in the triangular prism, a compensation block 13 needs to be added after the rhombus prism to compensate for the optical path difference between the two beams of light.

[0047] Therefore, in the optical front end 1, a group of ( After polarization diversity, two groups (each ) parallel beams with the same polarization state.

[0048] The spot radius of the Gaussian beam output from the two-dimensional collimator array 11 is , 99% of the light energy is distributed in the diameter The size of the pixel area allocated to a single port on the first LCOS chip 3 is In order to ensure the diffraction effect of the LCOS chip on the Gaussian beam and avoid mutual interference between ports, the following conditions must be met:

[0049] .

[0050] Since the waist of the Gaussian beam passing through the two-dimensional collimator array 11 is located on the first LCOS chip 3, the spot size at the output end face of the two-dimensional collimator array 11 will be larger than its waist size. Suppose the output spot size is , then the size of the pixel area allocated to a single port on the first LCOS chip 3 is limited to ,exist:

[0051] .

[0052] The light spot sizes on the first LCOS chip 3 and the second LCOS chip 6 are consistent. Figure 3 As shown, the first LCOS chip 3 and the second LCOS chip 6 are each divided into two upper and lower half areas, respectively processing a beam of polarized light separated by polarization diversity. The two half areas on the first LCOS chip 3 correspond to the two groups (each of which is 100 mm) output after polarization diversity through the optical front end 1. The two half areas on the second LCOS chip 6 correspond to the two groups (each of which is output after polarization diversity through the optical back end 7) Since the two-dimensional collimator array 11 has ports, so the size of the two LCOS chips is .

[0053] The pure phase-modulated LCOS chip is a pixelated element that can adjust the refractive index of the liquid crystal layer in each pixel through the electrically controlled birefringence effect, thereby adjusting the phase delay of the reflected light beam of each pixel. The LCOS chip can form a dynamic phase grating by adjusting the phase of each pixel, control the (reflective) diffraction direction of the light beam, and can be adjusted dynamically.

[0054] The LCOS chip consists of multiple blocks, and the pixel area size of each block is , a port of the optical front end of the corresponding matrix switch controls the diffraction direction of a beam of polarized light separated by polarization diversity and guides it to the target output port. The LCOS chip is equivalent to a "reflector" without the application of driving voltage; and under the condition of applying driving voltage, the diffraction deflection angle of the light beam is changed by electrical control to achieve the optical path switching between different ports.

[0055] The first prism group 2 has the same structure as the second prism group 5, and the present application is described with reference to the first prism group 2. The first prism group 2 is preferably designed as follows Figure 4 and Figure 5 Two structures are shown.

[0056] like Figure 4As shown, the first prism group 2 is formed by gluing two identical quadrangular prisms together. When viewed from the side, the quadrangular prism is a right-angled trapezoid. The right-angled thick ends of the two quadrangular prisms are aligned, and the first prism group 2 is a roof-shaped prism. Alternatively, a roof-shaped prism can be directly used instead.

[0057] like Figure 5 As shown, the first prism group 2 is composed of two identical prisms. When viewed from the side, the prisms are right triangles. The thin ends of the two prisms are aligned, and the first prism group 2 is V-shaped.

[0058] After the light beam passes through the first prism group 2, it will produce an additional deflection angle. Figure 4 and Figure 5 The two structures in the figure have the same deflection principle for the light beam, but the slopes are in opposite directions.

[0059] Next, Figure 4 Take the structure shown in the figure as an example to explain how it works. Figure 6 As shown, the inclination angle of the inclined surface of the first prism group 2 is , the refractive index of the material is The light beam is incident vertically on the surface of the first prism group, and the angle between it and the normal line of the inclined surface of the first prism group is , the angle between the light beam and the inclined surface after refraction is , then:

[0060] .

[0061] After being reflected by the first LCOS chip 3, the light beam passes through the inclined surface of the first prism group again, and the angle between the light beam and the normal line of the inclined surface is , by geometric calculation we can get:

[0062] .

[0063] The light beam is refracted by the inclined plane again and then emerges. The angle between the emergent light and the inclined plane is , then:

[0064] .

[0065] The final angle between the outgoing light and the incident light is .

[0066] The present application changes the additional deflection angle ( ), so that the two groups of light beams generated by the polarization diversity of the optical front end 1 are incident on the upper and lower halves of the second LCOS chip 6 respectively under the action of the concave reflector 4.

[0067] Preferably, in the large-port-count matrix optical switch, the first prism group, the first LCOS chip and the concave reflector need to simultaneously meet the following two conditions:

[0068]

[0069]

[0070] in, is the length of the first LCOS chip, is the focal length of the concave reflector, is the angle between the incident light and the normal of the incident surface of the first prism group, is the angle between the outgoing light and the normal of the outgoing surface of the first prism group, is the refractive index of the first prism group.

[0071] It should be noted that if Figure 6 As shown, the light beam has a lateral displacement after passing through the first prism group 2. Assume that the distance from the midpoint of the inclined surface of the first prism group 2 to the first LCOS chip 3 is , then the lateral offset .

[0072] In order to minimize the lateral offset, the first prism group 2 should be as close to the first LCOS chip 3 as possible. In the present application, the distance between the first prism group and the first LCOS chip is preferably in the range of [0, 1mm], and the distance between the second prism group and the second LCOS chip is in the range of [0, 1mm]. The thickness of the first prism group 2 As small as possible, but the thickness of the prism group If the thickness is too small, the processing difficulty will be increased and the prism will be fragile. In the present application, the thickness of the thinnest part of the prism assembly is preferably not less than 0.3 mm.

[0073] Preferably, the first prism group is rectangular in a top-view angle, and the length of the rectangle is greater than the length of the first LCOS chip ( ) is at least 2 mm larger, and the width of the rectangle is greater than the width of the first LCOS chip ( ) at least 2mm larger.

[0074] It should be noted that the present application prefers the above-mentioned length and width conditions to ensure that the first prism group 2 and the second prism group 5 can cover the light beams incident on the first LCOS chip 3 and the second LCOS chip 6 .

[0075] When no prism group is set in front of the LCOS chip, the equivalent optical path is as follows Figure 7 As shown in (a), the concave reflector 4 is equivalent to a lens. The light beams from all input ports are incident on the center position of the second LCOS chip 6 after being reflected by the first LCOS chip 3 and focused by the lens. Figure 8 In order to switch the beam to the edge port (upper left or upper right port), the width of the spot swept in the x direction is , the width swept in the y direction is , the maximum diffraction deflection angle in the x direction generated by the corresponding block on the first LCOS chip 3 is required to be , the maximum diffraction deflection angle in the y direction is .

[0076] When a prism group is added in front of the LCOS chip, and the first prism group 2 and the second prism group 5 adopt Figure 4 When the structure is shown, the equivalent optical path is Figure 7 As shown in (b) in the figure. The two groups of light beams generated by polarization diversity converge to the center of the concave reflector 4 after being refracted by the first prism group and reflected by the first LCOS chip 3. Since the introduction of the first prism group will apply an additional inward deflection to the light beams, the two groups of polarized light beams will no longer be incident on the center of the LCOS chip. The two groups of light beams will cross and respectively be incident on the center of the upper and lower halves of the second LCOS chip 6, as shown in FIG. Figure 8 As shown in (b) in the figure. For the same light beam, it will pass through the opposite half areas of the first LCOS chip 3 and the second LCOS chip 6, that is, pass through the upper half area once and the lower half area once. The second prism group 5 has the same structure as the first prism group 2 to offset the additional deflection applied to the light beam by the first prism group 2 and reduce the deflection angle required by the second LCOS chip 6. Finally, the two groups of light beams are received by the optical back end 7 at an angle parallel to the optical front end 1.

[0077] When the first prism group 2 and the second prism group 5 adopt Figure 5 When the structure is shown, the equivalent optical path is Figure 7 As shown in (c) in the figure. Since the introduction of the first prism group will apply an additional outward deflection to the light beam, the two groups of light beams generated by polarization diversity will be diverged to the upper and lower areas of the concave reflector 4 after being refracted by the first prism group and reflected by the first LCOS chip 3. The two groups of light beams no longer cross and are incident on the center positions of the upper and lower halves of the second LCOS chip 6 respectively, as shown in the figure. Figure 8 As shown in (b) in the figure. For the same light beam, it will pass through the same half area of ​​the first LCOS chip 3 and the second LCOS chip 6, that is, it will pass through the upper half area twice or the lower half area twice. The second prism group 5 has the same structure as the first prism group 2 to offset the additional deflection applied to the light beam by the first prism group 2 and reduce the deflection angle required by the second LCOS chip 6. Finally, the two groups of light beams are received by the optical back end 7 at an angle parallel to the optical front end 1.

[0078] To switch the beam to the edge port, the width of the beam spot in the x direction is , the width swept in the y direction is , the maximum diffraction deflection angle in the x direction generated by the corresponding block on the first LCOS chip 3 is required to be , the maximum diffraction deflection angle in the y direction is ,in, is the focal length of the concave reflector, is the number of ports of the optical front end, is the size of the pixel area allocated to a single port on the first LCOS chip.

[0079] It can be seen that after the prism group is set in front of the LCOS chip, the requirements for the diffraction deflection angle of the LCOS chip are reduced, further increasing the diffraction efficiency and reducing the loss of the matrix switch. In other words, when the diffraction deflection angle of the LCOS chip is constant, this optical design can realize a matrix switch with more ports.

[0080] Taking the 4K LCOS chip as an example, its resolution is 4096×2240, the pixel pitch is 3.6μm, and the overall size is 14.75mm×8.06mm. Since the LCOS chip is divided into two halves, the corresponding size of each half is 7.38mm×8.06mm. Assuming the focal length of the concave reflector is 30mm, the maximum deflection angle at this time is:

[0081]

[0082] therefore, Figure 7 The maximum diffraction deflection angle corresponding to the structure shown in (a) is 7.98°.

[0083] Figure 8 The corresponding method shown in (b) is Figure 7 The structures shown in (b) and (c) are the light spot distribution positions on the second LCOS chip 6, and the two polarized light beams are incident on the middle of the upper and lower halves of the second LCOS chip 6 respectively. At this time, the maximum deflection angle is:

[0084]

[0085] Figure 7 The maximum diffraction deflection angle corresponding to the structures shown in (b) and (c) is 5.20°. Figure 7 The maximum deflection angle of the structure in (a) is reduced by 34.8%.

[0086] When the maximum deflection angle of LCOS remains unchanged, Figure 7 The number of ports corresponding to the structure shown in (a) is 5×11, then Figure 7 The number of ports corresponding to the structures shown in (b) and (c) is 10×11. Figure 7 The number of ports in structure (a) has increased by 100%.

[0087] The present application also provides an optical communication device, comprising the large-port-count matrix optical switch and a circuit control board as described above; the circuit control board is used to provide a phase control signal for a first LCOS chip and a second LCOS chip in the large-port-count matrix optical switch.

[0088] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0089] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0090] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0091] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0092] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A large-port-count matrix optical switch based on a prism group, characterized in that: It includes an optical front end, a first prism group, a first LCOS chip, a concave reflector, a second prism group, a second LCOS chip and an optical back end which are sequentially arranged along a planar W-shaped optical path; The first LCOS chip and the second LCOS chip are both arranged on the focal plane of the concave reflector, and the three together constitute a 2F optical system; The first prism group and the second prism group have the same structure. The former applies additional deflections of the same magnitude and opposite directions to two groups of mutually parallel linear polarized lights after polarization diversity at each port of the optical front end through refraction on the xz plane. The latter applies additional deflections of the same magnitude and opposite directions to the linear polarized lights reflected by the concave reflector through refraction on the xz plane, so as to correct them to be mutually parallel. Under the premise that no driving voltage is applied to the first LCOS chip and the second LCOS chip, two groups of parallel light beams generated by polarization diversity from each port of the optical front end are refracted by the first prism group, reflected by the first LCOS chip, reflected by the concave reflector and refracted by the second prism group in sequence, and then are incident on the center positions of the upper and lower halves of the second LCOS chip respectively.

2. The large-port-count matrix optical switch according to claim 1, characterized in that: The distance between the first prism group and the first LCOS chip is in the range of [0, 1 mm], and the distance between the second prism group and the second LCOS chip is in the range of [0, 1 mm].

3. The large-port-count matrix optical switch according to claim 1, characterized in that: In the large-port-count matrix optical switch, the first prism group, the first LCOS chip and the concave reflector must simultaneously meet the following two conditions: in, is the number of ports in the x direction of the optical front end, is the side length of the pixel area allocated to a single port on the first LCOS chip, is the focal length of the concave reflector, is the angle between the incident light and the normal of the incident surface of the first prism group, is the angle between the outgoing light and the normal of the outgoing surface of the first prism group, is the refractive index of the first prism group.

4. The large-port-count matrix optical switch according to claim 3, characterized in that: The first prism group is formed by gluing two identical quadrangular prisms together. When viewed from the side, the quadrangular prism is a right-angled trapezoid. The right-angled thick ends of the two quadrangular prisms are aligned, and the first prism group is in the shape of a roof.

5. The large-port-count matrix optical switch according to claim 3, characterized in that: The first prism group is composed of two identical prisms. When viewed from the side, the prisms are right triangles. The thin ends of the two prisms are aligned, and the first prism group is V-shaped.

6. The large-port-count matrix optical switch according to claim 1, characterized in that: The thickness of the thinnest part of the prism group is not less than 0.3 mm.

7. The large-port-count matrix optical switch according to claim 1, characterized in that: The first prism group is a rectangle in a top view, the length of the rectangle is at least 2 mm greater than the length of the first LCOS chip, and the width of the rectangle is at least 2 mm greater than the width of the first LCOS chip.

8. The large-port-count matrix optical switch according to claim 1, characterized in that: The optical front end includes a two-dimensional collimator array, a polarization beam splitter prism, a compensation block and a half-wave plate; wherein, The two-dimensional collimator array includes a plurality of ports, each port is used to transform a small spot divergent light beam at the output end of the optical fiber into a large spot collimated light beam, which enters the polarization beam splitter prism; The polarization splitter prism is used to transmit p-waves and reflect s-waves, so that after polarization splitting, an incident beam of randomly polarized light is obtained into two beams of linear polarized light that are parallel to each other and have orthogonal polarization states. One of the beams of light passes through a compensation block to compensate for the optical path difference between the two beams of light, and after passing through a half-wave plate, the polarization state is rotated 90°. Finally, the two beams of light are parallel to each other and have the same polarization state, thus realizing polarization diversity.

9. The large-port-count matrix optical switch according to claim 1, characterized in that: The maximum diffraction deflection angle in the x direction generated by the corresponding block on the first LCOS chip , maximum diffraction deflection angle in the y direction ,in, is the focal length of the concave reflector, Indicates the number of ports in the x direction of the optical front end. Indicates the number of ports in the Y direction of the optical front end. is the side length of the pixel area allocated to a single port on the first LCOS chip.

10. An optical communication device, characterized in that: A large-port-count matrix optical switch and a circuit control board as claimed in any one of claims 1 to 9; The circuit control board is used to provide a phase control signal for the first LCOS chip and the second LCOS chip in the large-port-count matrix optical switch.

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