A wavelength selective switch

Abstract

The present invention provides a wavelength selection switch, which is applied in the field of optical communication and optical signal processing technology. The key points of the technical solution are: it includes an optical fiber array, a polarization processing optical group, a beam expansion and deflection auxiliary optical group, a beam compensation element, a dispersion optical element, a focusing optical group and a deflection engine. The optical fiber array emits a first light beam in a YZ plane and a second light beam in an XZ plane, respectively, so that the entire optical path is a double-pass optical path; the technical effect is: through the design of the optical path structure, it can meet the requirement of applying the same grating on the deflection engine, and diffracted light of different wavelengths can be returned to the same target optical fiber through the processing of the optical path structure, so that the complexity of the algorithm of the deflection engine can be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communication and optical signal processing, and in particular to a wavelength selection switch. Background Art

[0002] With the rapid development of optical communication technology, wavelength selective switch (WSS), as a core electronic component, has become an indispensable part of the intelligent all-optical switching network with its flexible wavelength selection and scheduling capabilities. And the wavelength selective switch realizes the precise selection and flexible scheduling of the wavelength of the optical signal through precise optical structure and control mechanism. Its basic principle is to use the diffraction effect of the grating and the switching function of the optical switch. When the optical signal emitted by the optical fiber first passes through a collimating lens to keep the light wave in a parallel state; then, the light wave is filtered by a grating or arrayed waveguide grating (AWG), and light waves of different wavelengths are separated; the separated light waves are sent to the optical switch array, and the optical switch returns the specified light wave to the corresponding output port according to the control signal to realize the selection and scheduling of the wavelength.

[0003] At present, the Chinese invention with the announcement number CN107976748A, the patent name is a multi-port wavelength selective switch based on polarization beam splitting double diffraction grating and its method, which discloses "the cylindrical mirror converts the light of different wavelengths after dispersion of the first light beam and the second light beam into parallel light beams parallel to each other, and narrows the circular light spot of the single wavelength light in the light beam into an elliptical light spot, which is projected onto the liquid crystal spatial light modulator, and the parallel light beams of different wavelengths in the same light beam are projected onto different pixel areas of the liquid crystal spatial light modulator, and the light beams of the same wavelength in the first and second light beams are projected onto the same pixel area of ​​the liquid crystal spatial light modulator. pixel area; load phase holographic gratings on pixel areas corresponding to different wavelengths of the liquid crystal spatial light modulator through the liquid crystal graphic loading control system, so that the reflected light of light beams of different wavelengths produces a diffraction effect on the yz plane, and the angle of the diffraction angle of the first-order light in the reflected light is changed by loading different phase holographic gratings; the first-order diffracted light of the first light beam of different wavelengths after the diffraction angle is adjusted returns along the direction where the second light beam reaches the liquid crystal spatial light modulator; the first-order diffracted light of the second light beam of different wavelengths after the diffraction angle is adjusted returns along the direction where the first light beam reaches the liquid crystal spatial light modulator.

[0004] However, in the existing wavelength selective switch, light beams of different wavelengths projected on the liquid crystal spatial light modulator return to the output fiber port, and different phase holographic gratings need to be loaded to change the diffraction angle of the first-order light in the reflected light. When a large number of phase holographic gratings need to be loaded, the algorithm of the wavelength selective switch system will become very complicated. Summary of the invention

[0005] The object of the present invention is to provide a wavelength selective switch, which has the advantage of being able to greatly reduce the complexity of the algorithm of the deflection engine.

[0006] To achieve the above objectives and other related objectives, the present invention provides the following technical solutions:

[0007] A wavelength selective switch includes a YZ plane and an XZ plane, including

[0008] An optical fiber array, wherein the optical fiber array emits a first light beam in a YZ plane and a second light beam in an XZ plane;

[0009] A polarization processing optical group, wherein the polarization processing optical group is used to separate the first light beam into two parallel light beams according to the polarization direction;

[0010] A beam expansion and deflection auxiliary optical group, which is used to expand the spot size of the two parallel light beams and the spot size of the second light beam to a desired size respectively;

[0011] A beam compensation element, the beam compensation element is used to compensate the light spots of the two beams of parallel light emitted from the beam expansion and deflection auxiliary optical group, and is used to compensate the light spot of the second light beam emitted from the beam expansion and deflection auxiliary optical group;

[0012] a dispersive optical element, the dispersive optical element being used to disperse the two beams of parallel light into two groups of first single-wavelength light including a plurality of different wavelengths along a dispersion direction, and being used to reflect the second light beam;

[0013] A focusing optical group, the focusing optical group is used to focus a plurality of first single wavelength lights of different wavelengths and to collimate a second light beam onto a deflection engine;

[0014] The first single wavelength lights of multiple different wavelengths are separated according to the wavelength size and focused on the deflection engine. After being reflected by the deflection engine, the first single wavelength lights of multiple different wavelengths return to the optical fiber along the original path.

[0015] The second light beam is collimated and incident on the deflection engine. Since a number of identical gratings are applied to the deflection engine, the second light beam undergoes a diffraction effect through the gratings. The diffracted light of different wavelengths has different angles with the Z axis. The diffracted light of multiple different wavelengths can be processed by a focusing optical group, a dispersive optical element, a beam compensation element, a beam expansion and deflection auxiliary optical group, and a polarization processing optical group and can return to the optical fiber of the same target.

[0016] In one embodiment of the present invention, a microlens array and a microprism array are disposed between the optical fiber array and the polarization processing optical group;

[0017] The microprism array comprises a first microprism array and a second microprism array, wherein the microprisms in the first microprism array are provided with an upper inclined surface inclined downward; and the microprisms in the second microprism array are provided with a lower inclined surface inclined upward;

[0018] The first microprism array is used to make the second light beam entering the upper microprism and originally propagating along the Z axis produce a downward deflection angle;

[0019] The second microprism array is used to make the second light beam entering the lower microprism and originally propagating along the Z axis produce an upward deflection angle.

[0020] In one embodiment of the present invention, the first micro-prism array is disposed above the second micro-prism array or the first micro-prism array is disposed below the second micro-prism array.

[0021] In one embodiment of the present invention, the polarization processing optical group includes a collimating cylindrical lens, a beam splitting crystal and a half-wave plate;

[0022] The first light beam enters the collimating cylindrical lens and then enters the spectroscopic crystal, which splits the first light beam into S polarized light and P polarized light. The half-wave plate is used to convert the S polarized light or the P polarized light so that the two polarized states of light become light of the same polarization state.

[0023] In one embodiment of the present invention, the beam expansion and deflection auxiliary optical group includes a YZ cylindrical lens a, an XZ cylindrical lens a, an XZ cylindrical lens b, an XZ cylindrical lens c, a YZ cylindrical lens b, and an XZ cylindrical lens d;

[0024] After the two beams of parallel light pass through the YZ cylindrical lens a and the YZ cylindrical lens b, the spot size is expanded to a desired size;

[0025] The second light beam converts the spot size to a desired size after passing through XZ cylindrical lens a, XZ cylindrical lens b, XZ cylindrical lens c, and XZ cylindrical lens d.

[0026] In one embodiment of the present invention, the beam compensation element is a compensation prism.

[0027] In one embodiment of the present invention, the dispersive optical element comprises a prism and a blazed grating disposed on one side of the prism;

[0028] Two beams enter the prism in parallel and reach the blazed grating. After being dispersed by the blazed grating, two groups of first single-wavelength lights including multiple different wavelengths are dispersed. The multiple first single-wavelength lights with different wavelengths are refracted out of the prism at different angles.

[0029] The second light beam enters the prism and reaches the blazed grating, and is reflected by the blazed grating and then refracted out of the prism.

[0030] In one embodiment of the present invention, the focusing optical group is a lens group composed of a plurality of concave lenses and convex lenses, and the deflection engine is located on the rear focal plane of the lens group combined optical system.

[0031] In one embodiment of the present invention, the focusing optical group includes two single-sided convex lenses, one single-sided concave lens and one double-sided concave lens, wherein the single-sided convex lens, the double-sided concave lens, the single-sided convex lens and the single-sided concave lens are arranged in sequence from the side of the dispersion optical element to the side of the deflection engine.

[0032] In one embodiment of the present invention, the deflection engine is one of a micro-electromechanical system MEMS, a liquid crystal on silicon LCOS, and a spatial light modulator.

[0033] As described above, a wavelength selective switch of the present invention has the following beneficial effects:

[0034] 1. On the YZ plane, the first light beam is emitted from the optical fiber array, separated by the polarization processing optical group, expanded by the beam expansion and deflection auxiliary optical group, compensated by the beam compensation element, dispersed by the dispersion optical element, and focused by the focusing optical group, so that light spots of different wavelengths are focused at different positions of the deflection engine, and after being reflected by the deflection engine, the first single wavelength light of different wavelengths returns to the optical fiber along the original path;

[0035] 2. On the XZ plane, the second light beam is emitted from the optical fiber array, and after passing through the microprism array, a deflection angle is generated for the second light beam originally propagating along the Z axis, and the beam expansion and deflection auxiliary optical group is converted, and the beam compensation element is compensated, and the dispersion optical element is reflected, and the focusing optical group is collimated, so that the second light beam is collimated and incident on the grating and a diffraction effect occurs. Multiple diffracted lights of different wavelengths have different angles with the Z axis. After being processed by the focusing optical group, the dispersion optical element, the beam compensation element, the beam expansion and deflection auxiliary optical group, and the polarization processing optical group, the diffracted lights of different wavelengths can return to the same target optical fiber;

[0036] Since the diffraction angles of light of different wavelengths diffracted on the same grating are different, in the prior art, in order for light of different wavelengths to return to the same target optical fiber, different gratings need to be applied to the light of different wavelengths, which greatly increases the complexity of the algorithm of the deflection engine. However, the wavelength selective switch, through the design of the optical path structure, can satisfy the requirement of applying the same grating on the deflection engine, and the diffracted light of different wavelengths can also return to the same target optical fiber through the processing of the optical path structure, thereby greatly reducing the complexity of the algorithm of the deflection engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the overall optical path structure in the YZ plane of an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of the positions of the optical fiber array, microlens array, and microprism array in the XZ plane according to an embodiment of the present invention;

[0039] Figure 3 is a side view of a microprism array according to an embodiment of the present invention;

[0040] Figure 4 is a schematic structural diagram of a polarization processing optical group in a YZ plane according to an embodiment of the present invention;

[0041] Figure 5 is a schematic structural diagram of a dispersive optical element in a YZ plane according to an embodiment of the present invention;

[0042] Figure 6 Schematic diagram of a light spot on a deflection engine in an XY plane according to an embodiment of the present invention.

[0043] Figure numerals: 1. optical fiber array; 2. polarization processing optical group; 21. collimating cylindrical lens; 22. spectroscopic crystal; 23. half-wave plate; 3. beam expansion and deflection auxiliary optical group; 31. YZ cylindrical lens a; 32. XZ cylindrical lens a; 33. XZ cylindrical lens b; 34. XZ cylindrical lens c; 35. YZ cylindrical lens b; 36. XZ cylindrical lens d; 4. beam compensation element; 5. dispersion optical element; 51. prism; 52. blazed grating; 6. focusing optical group; 61. single-sided convex lens; 62. single-sided concave lens; 63. double-sided concave lens; 7. deflection engine; 8. microlens array; 9. microprism array; 10. first microprism array; 11. second microprism array; 12. grating. DETAILED DESCRIPTION

[0044] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0045] See also Figures 1 to 6 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0046] See also Figure 1 , the present invention provides a wavelength selective switch, comprising an optical fiber array 1, a polarization processing optical group 2, a beam expansion and deflection auxiliary optical group 3, a beam compensation element 4, a dispersion optical element 5, a focusing optical group 6 and a deflection engine 7;

[0047] The optical fiber array 1 emits a first light beam in the YZ plane and a second light beam in the XZ plane, and both the first light beam and the second light beam propagate along the Z axis.

[0048] See also Figure 1 , Figure 2 and Figure 3 A microlens array 8 and a microprism array 9 are disposed between the optical fiber array 1 and the polarization processing optical group 2; each optical fiber corresponds to a microlens, and each microlens corresponds to a microprism;

[0049] The microprism array 9 includes a first microprism array 10 and a second microprism array 11, wherein the first microprism array 10 can be arranged above the second microprism array 11, or the first microprism array 10 can be arranged below the second microprism array 11. In this embodiment, it is preferred that the first microprism array 10 can be arranged above the second microprism array 11.

[0050] The microprisms in the first microprism array 10 are provided with an upper inclined surface inclined downward; the microprisms in the second microprism array 11 are provided with a lower inclined surface inclined upward; the first microprism array 10 is used to make the second light beam entering the upper microprism and originally propagating along the Z axis produce a downward deflection angle; the second microprism array 11 is used to make the second light beam entering the lower microprism and originally propagating along the Z axis produce an upward deflection angle.

[0051] In the YZ plane, the optical fiber array 1 emits a first light beam, which is collimated after passing through the microlens array 8, and then enters the polarization processing optical group 2 through the microprism; wherein the microprism array 9 does not change the shape of the first light beam in the YZ plane;

[0052] In the XY plane, the optical fiber array 1 emits the second light beam, the first light beam passes through the microlens array 8 and is collimated, and then passes through the microprism array 9. The second light beam originally propagating along the Z axis in the upper half generates a downward deflection angle after passing through the first microprism array 10, and the second light beam originally propagating along the Z axis in the lower half generates a downward deflection angle after passing through the second microprism array 11. The deflection angle in this embodiment can be 3°, and then enters the polarization processing optical group 2;

[0053] The microprism array 9 generates a deflection angle for the second light beam originally propagating along the Z axis, so that the two parts of light can be multiplexed into one optical path structure, and the light spots of the upper second light beam and the lower second light beam can be separated by a suitable distance on the deflection engine 7.

[0054] See also Figure 1 and Figure 4 The polarization processing optical group 2 is used to separate the first light beam into two parallel light beams according to the polarization direction. The polarization processing optical group 2 includes a collimating cylindrical lens 21, a beam splitting crystal 22 and a half-wave plate 23. The beam splitting crystal 22 in this embodiment is a uniaxial beam splitting crystal 22;

[0055] The beam splitting crystal 22 is used to split the first light beam into S polarized light and P polarized light. The half-wave plate 23 is used to convert the S polarized light or the P polarized light so that the two polarized states of light become light of the same polarized state. In this embodiment, the half-wave plate 23 converts the P polarized light into the S polarized light.

[0056] In the YZ plane, the first light beam enters the collimating cylindrical lens 21, which further transforms the spot of the first light beam to the size required by the design, and then enters the spectroscopic crystal 22 and the half-wave plate 23, which separate the first light beam into two parallel light beams according to the polarization direction, wherein the separation distance is determined by the thickness of the spectroscopic crystal 22 and the optical axis direction of the crystal; and then enters the beam expansion and deflection auxiliary optical group 3;

[0057] In the XZ plane, the second light beam passes through the polarization processing optical group 2, wherein the optical elements in the polarization processing optical group 2 only act as flat glass and do not change the shape of the second light beam, and then enters the beam expansion and deflection auxiliary optical group 3.

[0058] See also Figure 1 The beam expansion and deflection auxiliary optical group 3 is used to expand the spot size of the two parallel light beams to the required size and convert the spot size of the second light beam to the required size; the beam expansion and deflection auxiliary optical group 3 includes a YZ cylindrical lens a31, an XZ cylindrical lens a32, an XZ cylindrical lens b33, an XZ cylindrical lens c34, a YZ cylindrical lens b35, and an XZ cylindrical lens d36;

[0059] The two parallel beams of light are expanded to the required size after passing through the YZ cylindrical lens a31 and the YZ cylindrical lens b35;

[0060] The second light beam passes through XZ cylindrical lens a32, XZ cylindrical lens b33, XZ cylindrical lens c34, and XZ cylindrical lens d36 to convert the spot size to the required size;

[0061] In the YZ plane, the two parallel light beams pass through the 4f structure composed of the YZ cylindrical lens a31 and the YZ cylindrical lens b35, and the spot size is expanded to the size required by the design; wherein the XZ cylindrical lens a32, the XZ cylindrical lens b33, the XZ cylindrical lens c34, and the XZ cylindrical lens d36 in the YZ plane only play the role of flat glass and do not change the shape of the two parallel light beams; and then enter the beam compensation element 4;

[0062] In the XZ plane, the second light beam passes through the 4f system composed of XZ cylindrical lens a32, XZ cylindrical lens b33, XZ cylindrical lens c34, and XZ cylindrical lens d36, and the light spot is transformed to the size required by the design. Among them, in the XZ plane, YZ cylindrical lens a31 and YZ cylindrical lens b35 only act as flat glass and do not change the shape of the second light beam, and then enters the beam compensation element 4.

[0063] See also Figure 1 , a beam compensation element 4, the beam compensation element 4 is used to compensate the light spots of the two beams of parallel light emitted from the beam expansion and deflection auxiliary optical group 3, and is used to compensate the light spot of the second light beam emitted from the beam expansion and deflection auxiliary optical group 3; the beam compensation element 4 in this embodiment is a compensation prism;

[0064] In the YZ plane, after the two parallel light beams enter the compensation prism, the direction of the exit light spot is changed, and the light spot size is changed (if the incident light enters the isosceles prism 51 at the minimum deviation angle, the exit light spot size remains unchanged), and then enter the dispersive optical element 5;

[0065] In the XZ plane, after the second light beam enters the compensation prism, the direction of the exit spot is changed, and the spot size is changed, and then it enters the dispersive optical element 5;

[0066] In the XZ plane, the compensation prism can compensate for the deflection of the second light beam spot, so that the spots of all wavelengths on the deflection engine 7 are long elliptical spots instead of curved spots; if no compensation is made, curved spots will appear, making it difficult and inaccurate to position the wavelength on the deflection engine 7, thereby reducing the bandwidth of the wavelength selection switch.

[0067] See also Figure 1 and Figure 5 The dispersive optical element 5 is used to disperse the two parallel light beams into two groups of first single wavelength light including a plurality of different wavelengths along the dispersion direction; and is used to reflect the second light beam; wherein the dispersive optical element 5 comprises a prism 51 and a blazed grating 52 attached to one side of the prism 51; wherein the combination of the prism 51 and the blazed grating 52 can improve the light dispersion capability;

[0068] The two beams enter the prism 51 in parallel and reach the blazed grating 52. After being dispersed by the blazed grating 52, two groups of first single-wavelength lights including a plurality of different wavelengths are dispersed. The plurality of first single-wavelength lights with different wavelengths are refracted out of the prism 51 at different angles.

[0069] The second light beam enters the prism 51 and reaches the blazed grating 52, and is reflected by the blazed grating 52 and then refracted out of the prism 51;

[0070] In the YZ plane, two parallel light beams enter the prism 51 through the incident surface, and then reach the blazed grating 52. After being dispersed by the blazed grating 52, two groups of first single-wavelength lights including multiple different wavelengths are produced. The first single-wavelength lights of different wavelengths have different diffraction angles, and then are refracted out of the prism 51 through the exit surface, and the angle between the long and short waves is magnified; and then enter the focusing optical group;

[0071] In the XZ plane, the second light beam passes through the prism 51, is reflected by the blazed grating 52, and then is refracted out through the prism 51; and then enters the focusing optical group.

[0072] See also Figure 1 and Figure 6 , the focusing optical group 6 is used to focus the first single wavelength light and the second light beam of multiple different wavelengths onto the deflection engine 7;

[0073] The focusing optical group 6 is a lens group composed of several concave lenses and convex lenses, wherein the deflection engine 7 is located on the rear focal plane of the lens group combined optical system; the focusing optical group 6 includes two single-sided convex lenses 61, one single-sided concave lens 62 and one double-sided concave lens 63, wherein from the side of the dispersion optical element 5 to the side of the deflection engine 7, the single-sided convex lens 61, the double-sided concave lens 63, the single-sided convex lens 61 and the single-sided concave lens 62 are arranged in sequence.

[0074] In the YZ plane, a plurality of first single wavelength lights of different wavelengths are focused onto the deflection engine 7 through the focusing optical group 6;

[0075] In the XZ plane, the second light beam is collimated onto the deflection engine 7 through the focusing optical group 6 .

[0076] See also Figure 2 , the deflection engine 7 in this embodiment may be one of a micro-electromechanical system MEMS, a liquid crystal on silicon LCOS, and a spatial light modulator;

[0077] The first single wavelength lights of multiple different wavelengths are separated according to the wavelength size by the focusing optical group 6 and focused on the XY plane of the deflection engine 7. After being reflected by the deflection engine 7, the first single wavelength lights of multiple different wavelengths return to the optical fiber of the YZ plane along the original path.

[0078] The second light beam is collimated and incident on the deflection engine 7 along the direction of the Z axis in the XZ plane. Since a number of identical gratings 12 are applied to the deflection engine 7, the gratings 12 in this embodiment are also blazed gratings. The second light beam undergoes a diffraction effect through the grating 12, and a plurality of diffracted lights of different wavelengths have different angles with the Z axis. The diffracted lights of different wavelengths are processed by the focusing optical group 6, the dispersive optical element 5, the beam compensation element 4, the beam expansion and deflection auxiliary optical group 3, and the polarization processing optical group 2 and can return to the optical fiber of the same target.

[0079] In summary, the present invention can satisfy the requirement of applying the same grating on the deflection engine 7 through the design of the optical path structure, and the diffracted light of different wavelengths can be returned to the same target optical fiber through the processing of the optical path structure, thereby greatly reducing the complexity of the algorithm of the deflection engine 7.

[0080] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A wavelength selective switch, comprising a YZ plane and an XZ plane, characterized in that: include An optical fiber array (1), wherein the optical fiber array (1) emits a first light beam in a YZ plane and a second light beam in an XZ plane; A polarization processing optical group (2), wherein the polarization processing optical group (2) is used to separate the first light beam into two parallel light beams according to the polarization direction; A beam expansion and deflection auxiliary optical group (3), the beam expansion and deflection auxiliary optical group (3) is used to expand the spot size of the two parallel light beams and the spot size of the second light beam to a desired size; the beam expansion and deflection auxiliary optical group (3) comprises a YZ cylindrical lens a (31), an XZ cylindrical lens a (32), an XZ cylindrical lens b (33), an XZ cylindrical lens c (34), a YZ cylindrical lens b (35), and an XZ cylindrical lens d (36); After the two beams of parallel light pass through the YZ cylindrical lens a (31) and the YZ cylindrical lens b (35), the spot size is expanded to a desired size; The second light beam passes through XZ cylindrical lens a (32), XZ cylindrical lens b (33), XZ cylindrical lens c (34), and XZ cylindrical lens d (36) to convert the spot size to a desired size; A beam compensation element (4), the beam compensation element (4) being used to compensate for the light spots of two beams of parallel light emitted from the beam expansion and deflection auxiliary optical group (3), and being used to compensate for the light spot of a second light beam emitted from the beam expansion and deflection auxiliary optical group (3); A dispersive optical element (5), the dispersive optical element (5) being used to disperse two beams of parallel light into two groups of first single-wavelength light including a plurality of different wavelengths along a dispersion direction, and being used to reflect a second light beam; the dispersive optical element (5) comprising a prism (51) and a blazed grating (52) arranged on one side of the prism (51); The two beams enter the prism (51) in parallel and reach the blazed grating (52). After being dispersed by the blazed grating (52), two groups of first single-wavelength lights including a plurality of different wavelengths are dispersed. The plurality of first single-wavelength lights with different wavelengths are refracted out of the prism (51) at different angles. The second light beam enters the prism (51) and reaches the blazed grating (52), and is reflected by the blazed grating (52) and then refracted out of the prism (51); A focusing optical group (6), the focusing optical group (6) being used to focus a first single wavelength light of a plurality of different wavelengths and collimate a second light beam onto a deflection engine (7); the focusing optical group (6) comprising two single-sided convex lenses (61), a single-sided concave lens (62) and a double-sided concave lens (63), wherein the single-sided convex lens (61), the double-sided concave lens (63), the single-sided convex lens (61) and the single-sided concave lens (62) are arranged in sequence from one side of the dispersion optical element (5) to the side of the deflection engine (7); The first single wavelength lights of multiple different wavelengths are separated according to the size of the wavelengths and focused on the deflection engine (7), and after being reflected by the deflection engine (7), the first single wavelength lights of multiple different wavelengths return to the optical fiber along the original path; The second light beam is collimated and incident on the deflection engine (7). Since a plurality of identical gratings (12) are applied to the deflection engine (7), the second light beam undergoes a diffraction effect through the grating (12). The diffracted light beams of different wavelengths have different angles with the Z axis. The diffracted light beams of multiple different wavelengths are processed by a focusing optical group (6), a dispersive optical element (5), a beam compensation element (4), a beam expansion and deflection auxiliary optical group (3), and a polarization processing optical group (2) and can return to the same target optical fiber.

2. A wavelength selective switch according to claim 1, characterized in that: A microlens array (8) and a microprism array (9) are arranged between the optical fiber array (1) and the polarization processing optical group (2); The microprism array (9) comprises a first microprism array (10) and a second microprism array (11); the microprisms in the first microprism array (10) are provided with an upper inclined surface inclined downward; and the microprisms in the second microprism array (11) are provided with a lower inclined surface inclined upward; The first microprism array (10) is used to cause the second light beam entering the upper microprism and originally propagating along the Z axis to produce a downward deflection angle; The second microprism array (11) is used to cause the second light beam entering the lower microprism and originally propagating along the Z axis to produce an upward deflection angle.

3. A wavelength selective switch according to claim 2, characterized in that: The first microprism array (10) is arranged above the second microprism array (11) or the first microprism array (10) is arranged below the second microprism array (11).

4. A wavelength selective switch according to claim 1, characterized in that: The polarization processing optical group (2) comprises a collimating cylindrical lens (21), a beam splitting crystal (22) and a half-wave plate (23); The first light beam enters the collimating cylindrical lens (21) and then enters the beam splitting crystal (22). The beam splitting crystal (22) splits the first light beam into S-polarized light and P-polarized light. The half-wave plate (23) is used to convert the S-polarized light or the P-polarized light so that the light in the two polarization states becomes light in the same polarization state.

5. A wavelength selective switch according to claim 1, characterized in that: The beam compensation element (4) is a compensation prism.

6. A wavelength selective switch according to claim 1, characterized in that: The deflection engine (7) is one of a micro-electromechanical system MEMS, liquid crystal on silicon LCOS, and a spatial light modulator.

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