CN116466436A - Wavelength selective switch - Google Patents
Wavelength selective switch Download PDFInfo
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- CN116466436A CN116466436A CN202310276000.3A CN202310276000A CN116466436A CN 116466436 A CN116466436 A CN 116466436A CN 202310276000 A CN202310276000 A CN 202310276000A CN 116466436 A CN116466436 A CN 116466436A
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- 239000006185 dispersion Substances 0.000 claims abstract description 40
- 238000000926 separation method Methods 0.000 claims abstract description 19
- 238000003384 imaging method Methods 0.000 claims description 19
- 239000004973 liquid crystal related substance Substances 0.000 claims description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 10
- 229910052710 silicon Inorganic materials 0.000 claims description 10
- 239000010703 silicon Substances 0.000 claims description 10
- 230000003287 optical effect Effects 0.000 abstract description 52
- 238000004891 communication Methods 0.000 abstract description 5
- 238000011165 process development Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 239000013307 optical fiber Substances 0.000 description 4
- 230000010287 polarization Effects 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29304—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating
- G02B6/29305—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by diffraction, e.g. grating as bulk element, i.e. free space arrangement external to a light guide
- G02B6/29308—Diffractive element having focusing properties, e.g. curved gratings
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29371—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating principle based on material dispersion
- G02B6/29373—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating principle based on material dispersion utilising a bulk dispersive element, e.g. prism
Abstract
The invention discloses a wavelength selective switch, and belongs to the technical field of optical communication. Aiming at the problems that a switch lens of a WSS optical system structure in the prior art is close to other optical elements or light paths, so that the occupied space of the switch lens is large, the position and the angle of the switch lens are required to be combined with other optical elements to adjust the light paths, so that the process development difficulty is large, and the like, the invention provides a wavelength selective switch. Therefore, the self-focusing dispersion prism grating is used for wavelength separation of polarized light beams in the WSS optical system structure, a switch lens is not required, and optical path adjustment is not required to be carried out by combining other optical elements, so that the WSS optical system structure is simpler.
Description
Technical Field
The invention relates to the technical field of optical communication, in particular to a wavelength selective switch.
Background
The reconfigurable optical differential multiplexing system (ROADM, reconfigurable Optical Add-Drop Multiplexer) can realize optical signal switching, attenuation or blocking of any wavelength or wavelength combination at any communication port in an optical communication network, and is core optical switching equipment for flexible scheduling of the optical communication network. Wavelength selective switches (WSS, wavelength Selective Switches) are core modules for implementing ROADM system functions, and are mainly classified into WSS based on Liquid Crystal on silicon (LCoS, liquid Crystal On Silicon) technology, liquid Crystal (LC) technology and microelectromechanical system (MEMS, micro-Electro-Mechanical System) technology according to technical principles, where WSS based on LCoS technology has a feature of flexible grid configuration, i.e., a communication center frequency and bandwidth can be flexibly set, and thus gradually becomes a mainstream of market applications.
The WSS based on the LCoS technology mainly comprises the steps of utilizing a dispersion grating to focus light with different wavelengths to different positions on the surface of the LCoS respectively in an imaging mode, performing spatial separation so as to facilitate independent processing of each wavelength, enabling the LCoS to form an elliptical light spot, enabling the major axis direction to be a switching direction, enabling the minor axis direction to be a wavelength arrangement direction, enabling the LCoS to form a phase diffraction grating in the light spot major axis direction (switching direction) in order to realize switching of different ports of the WSS, and enabling energy to be concentrated in one diffraction order and output to a corresponding WSS port. In the prior art, the switch lens of most WSS optical system structures is close to a wave plate and a prism grating or a light path, and the occupied space of the switch lens is large, so that other structural parts need to be provided with a certain light-transmitting caliber safety margin for reduction, and the WSS is not beneficial to miniaturization; in addition, the position and angle of the switch lens need to be combined with other optical elements to adjust the light path, including the adjustment of the position and the angle, and the difficulty and the cost of process development are increased.
Through searching, chinese patent application, application number 201811330506.3, publication date 2018, 11, 9 discloses a wavelength selective switch. The wavelength selective switch of the invention comprises: the optical fiber array, the concave grating and the control chip; the optical fiber array is used for inputting optical signals into the concave grating; the concave grating is used for realizing the light spot conversion of the optical signals and then making the optical signals after the light spot conversion incident to the control chip; the control chip is used for controlling the optical signal to perform optical signal operation. The scheme adopts a single concave grating to replace a shaping lens, a diffraction grating and a converging lens in the prior art, so that the problem of excessive optical elements of the conventional wavelength selective switch is solved, but the scheme does not consider the problems of occupied space, position and angle of the switch lens in the practical application process, so that the scheme has strong practicability and applicability.
Disclosure of Invention
1. Technical problem to be solved
Aiming at the problems that in the prior art, the switch lens of the WSS optical system structure is large in occupied space due to the fact that the switch lens is close to optical elements such as a wave plate or an optical path is close, the development difficulty of an optical path adjustment process is high due to the fact that the position and the angle of the switch lens are required to be combined with other optical elements, and the like, the invention provides the wavelength selective switch.
2. Technical proposal
The aim of the invention is achieved by the following technical scheme.
A wavelength selective switch comprising a polarized light beam, the wavelength selective switch comprising a self-focusing dispersive prism grating; the self-focusing dispersion prism grating comprises a prism and a second lens, wherein the second lens is connected to one side of the prism to form the self-focusing dispersion prism grating, and the prism and the second lens are sequentially arranged along the incidence direction of polarized light beams; the self-focusing dispersion prism grating is used for realizing the wavelength separation of polarized light beams.
Further, the second lens comprises a diffraction grating and a self-focusing lens, the diffraction grating covers one side of the self-focusing lens to form the second lens, and the self-focusing lens and the diffraction grating are sequentially arranged along the incidence direction of the polarized light beam.
Further, the self-focusing lens is a graded index lens.
Further, the refractive index of the self-focusing lens along the switching direction is:
where x represents the distance from the center, n represents the refractive index, n (x) represents the refractive index at the position corresponding to the switching direction, and a represents the refractive index distribution constant.
Further, the self-focusing lens focal length is expressed as:
where f represents the self-focusing lens focal length and L represents the self-focusing lens thickness.
Further, the polarized light beam enters the self-focusing lens again after being reflected by the diffraction grating to form a combined focal length, and the combined focal length of the self-focusing lens is expressed as:
wherein F represents the self-focusing lens combined focal length.
Further, the wavelength selective switch also comprises a reflective imaging mirror and a silicon-based liquid crystal device; the reflection imaging lens reflects the polarized light beam to the self-focusing dispersion prism grating, the self-focusing dispersion prism grating separates the wavelength of the polarized light beam, the self-focusing dispersion prism grating reflects the polarized light beam after the wavelength separation to the reflection imaging lens, and the reflection imaging lens reflects the polarized light beam after the wavelength separation to the silicon-based liquid crystal device to form a circular light spot.
3. Advantageous effects
Compared with the prior art, the invention has the advantages that:
according to the wavelength selective switch provided by the invention, the self-focusing dispersion prism grating is used for separating the wavelength of the light beam in the WSS optical system structure, and the switch lens is not required to be used, so that the problem that the switch lens is spatially interfered with other optical elements or light paths is avoided, and the WSS optical system structure is effectively simplified; meanwhile, the self-focusing dispersion prism grating is used without combining other optical elements to adjust the light path, so that the process development difficulty is simplified, and the development cost is greatly reduced.
Drawings
FIG. 1 is a schematic diagram of the overall structure of the present invention;
FIG. 2 is a schematic diagram of a self-focusing dispersion prism grating structure according to an embodiment;
FIG. 3 is a schematic diagram of a diffraction grating structure according to an embodiment;
FIG. 4 is a schematic diagram of a diffraction grating-covered self-focusing lens structure according to an embodiment;
FIG. 5 is a graph of the path of an embodiment beam traveling in the direction of the self-focusing lens switch;
FIG. 6 is a graph of the path of an embodiment beam traveling in the direction of chromatic dispersion of a self-focusing lens.
The reference numerals in the figures illustrate: 1. an optical fiber; 2. a first lens; 3. a polarization separation assembly; 4. a birefringent crystal; 5. a wave plate; 6. a reflective imaging mirror; 7. a self-focusing dispersion prism grating; 71. a prism; 72. a second lens; 721. a diffraction grating; 722. a self-focusing lens; 8. a liquid crystal on silicon device; 9. the light beam is polarized.
Detailed Description
The invention will now be described in detail with reference to the drawings and the accompanying specific examples.
Examples
In the conventional WSS optical system structure, the wavelength separation of the light beam is achieved by the combined action of the dispersion prism and the switching lens, which is closer to other optical elements such as the dispersion prism or the optical path. However, in practical applications, a certain safety margin of the light transmission aperture needs to be reserved between each optical element, and the switch lens occupies a large space because the switch lens is close to other optical elements such as a dispersion prism or the optical path. As the overall size requirement of the WSS optical system structure is smaller, the problem is more prominent, and the miniaturization of the WSS optical system structure is not facilitated. In addition, in the existing WSS optical system structure, the position and the angle of the switch lens are required to be combined with other optical elements to adjust the optical path, so that the development difficulty and the cost of the WSS optical system structure process are increased.
As shown in fig. 1-6, a wavelength selective switch is provided in this embodiment. The wavelength selective switch comprises a polarized light beam 9, the wavelength selective switch further comprises a self-focusing dispersion prism grating 7, the self-focusing dispersion prism grating 7 comprises a prism 71 and a second lens 72, the second lens 72 is connected to one side of the prism 71 to form the self-focusing dispersion prism grating 7, and the prism 71 and the second lens 72 are sequentially arranged along the incident direction of the polarized light beam 9; the self-focusing dispersion prism grating 7 is used for realizing wavelength separation of polarized light beams 9.
In this embodiment, as shown in fig. 2, the self-focusing dispersion prism grating 7 includes a prism 71 and a second lens 72, and the second lens 72 is connected to the prism 71 to form the self-focusing dispersion prism grating 7. In this embodiment, the second lens 72 may be attached to one side of the prism 71 by bonding or other similar means, and the prism 71 and the second lens 72 are sequentially arranged along the incident direction of the polarized light beam 9. Further, as shown in fig. 4, the second lens 72 includes a diffraction grating 721 and a self-focusing lens 722, wherein the diffraction grating 721 covers the self-focusing lens 722 to form the second lens 72, and the self-focusing lens 722 and the diffraction grating 721 are sequentially arranged along the incident direction of the polarized light beam 9. As shown in fig. 3, the diffraction grating 721 is provided with a plurality of lines distributed at equal intervals, and the diffraction grating 721 is covered on one side of the self-focusing lens 722 in parallel along the line direction. Note that, in the WSS optical system structure, a switching direction and a dispersion direction are included. Further, the prism 71 is used for dispersing the polarized light beam 9; in this embodiment, the prism 71 includes a prism, a right-angle prism, a pentagonal prism, etc., and preferably, an equilateral prism is selected in this embodiment. The diffraction grating 721 is used to disperse the polarized light beam 9, and the self-focusing lens 722 is used to change the refractive index of the polarized light beam 9 in the on-off direction. It is noted that the self-focusing lens 722 is a graded index lens, i.e., theThe self-focusing lens 722 may achieve a graded index of refraction in the on-off direction while maintaining a fixed index of refraction in the dispersion direction. As shown in FIG. 4, n 1 For the refractive index of the polarized light beam 9 in the on-off direction, n, through the second lens 72 2 Is the refractive index of the polarized light beam 9 in the direction of dispersion through the second lens 72. As shown in fig. 5, a track diagram of the polarized light beam 9 traveling in the on-off direction of the self-focusing lens 722 shows that the refractive index of the polarized light beam 9 changes gradually in the on-off direction of the self-focusing lens 722; as shown in fig. 6, the track diagram of the polarized light beam 9 traveling in the dispersion direction of the self-focusing lens 722 shows that the refractive index of the polarized light beam 9 in the dispersion direction of the self-focusing lens 722 is fixed.
Further, the refractive index of the self-focusing lens 722 along the switching direction is:
where x represents the distance from the center, n represents the refractive index, n (x) represents the refractive index at the position corresponding to the switching direction, and a represents the refractive index distribution constant.
The focal length of the self-focusing lens 722 is:
where f denotes the focal length of the self-focusing lens 722 and L denotes the thickness of the self-focusing lens 722.
It should be noted that, after being reflected by the diffraction grating 721, the polarized light beam 9 enters the self-focusing lens 722 again to generate a focal length, where the focal length forms a combined focal length with the focal length f of the self-focusing lens 722, and the combined focal length of the self-focusing lens 722 is:
where F represents the combined focal length of the self-focusing lens 722.
In this embodiment, the wavelength selective switch further comprises a reflective imaging mirror 6 and a liquid crystal on silicon device 8. The reflective imaging mirror 6 is used to achieve collimation of the polarized light beam 9. The reflection imaging mirror 6 makes the polarized light beam 9 incident into the self-focusing dispersion prism grating 7, the self-focusing dispersion prism grating 7 separates the wavelength of the polarized light beam 9, the self-focusing dispersion prism grating 7 reflects the polarized light beam 9 after the wavelength separation to the reflection imaging mirror 6, and the reflection imaging mirror 6 reflects the polarized light beam 9 after the wavelength separation to the liquid crystal on silicon device 8 to form a circular light spot.
Specifically, as shown in fig. 1, the first lens 2 performs primary collimation on the light beam emitted from the optical fiber 1, and the polarization separation component 3 performs polarization spatial separation on the light beam, so as to obtain two polarized light beams 9; further, after passing through the birefringent crystal 4, the two polarized light beams 9 are unified in polarization direction through the wave plate 5; the two polarized light beams 9 are then collimated by the reflective imaging mirror 6 and then are incident into the self-focusing dispersion prism grating 7 for wavelength separation, specifically, the two polarized light beams 9 sequentially pass through the prism 71, the self-focusing lens 722 and the diffraction grating 721 along the incident direction of the two polarized light beams 9, the self-focusing dispersion prism grating 7 reflects the polarized light beams 9 after wavelength separation to the reflective imaging mirror 6, specifically, the two polarized light beams 9 after wavelength separation sequentially pass through the diffraction grating 721, the self-focusing lens 722 and the prism 71 and then are emitted into the reflective imaging mirror 6, and the reflective imaging mirror 6 reflects the polarized light beams 9 after wavelength separation into the silicon-based liquid crystal device 8 to form circular light spots. Therefore, according to the wavelength selective switch, the self-focusing dispersion prism grating 7 is used for replacing a dispersion prism and a switch lens in the traditional WSS optical system structure, so that the WSS optical system structure is simplified, the problem that the switch lens is spatially interfered with an optical path or other optical elements is avoided, and the structural volume of the WSS optical system is further reduced; meanwhile, since the diffraction grating 721 covers one side of the self-focusing lens 722, the optical axis of the self-focusing lens 722 is perpendicular to the grating surface, and the optical path adjustment is not required, so that the process development is greatly simplified.
The foregoing has been described schematically the invention and embodiments thereof, which are not limiting, but are capable of other specific forms of implementing the invention without departing from its spirit or essential characteristics. The drawings are also intended to depict only one embodiment of the invention, and therefore the actual construction is not intended to limit the claims, any reference number in the claims not being intended to limit the claims. Therefore, if one of ordinary skill in the art is informed by this disclosure, a structural manner and an embodiment similar to the technical scheme are not creatively designed without departing from the gist of the present invention, and all the structural manners and the embodiment are considered to be within the protection scope of the present patent. In addition, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" preceding an element does not exclude the inclusion of a plurality of such elements. The various elements recited in the product claims may also be embodied in software or hardware. The terms first, second, etc. are used to denote a name, but not any particular order.
Claims (7)
1. A wavelength selective switch comprising a polarized light beam (9), characterized in that the wavelength selective switch comprises a self-focusing dispersive prism grating (7); the self-focusing dispersion prism grating (7) comprises a prism (71) and a second lens (72), wherein the second lens (72) is connected to one side of the prism (71) to form the self-focusing dispersion prism grating (7), and the prism (71) and the second lens (72) are sequentially arranged along the incidence direction of the polarized light beam (9); the self-focusing dispersion prism grating (7) is used for realizing wavelength separation of polarized light beams (9).
2. A wavelength selective switch according to claim 1, characterized in that the second lens (72) comprises a diffraction grating (721) and a self-focusing lens (722), the diffraction grating (721) is covered on one side of the self-focusing lens (722) to form the second lens (72), and the diffraction grating (721) and the self-focusing lens (722) are arranged in sequence along the incidence direction of the polarized light beam (9).
3. A wavelength selective switch according to claim 2, characterized in that said self-focusing lens (722) is a graded index lens.
4. A wavelength selective switch according to claim 3, characterized in that the refractive index of the self-focusing lens (722) in the switching direction is:
where x represents the distance from the center, n represents the refractive index, n (x) represents the refractive index at the position corresponding to the switching direction, and a represents the refractive index distribution constant.
5. A wavelength selective switch according to claim 4, characterized in that the self-focusing lens (722) focal length is expressed as:
where f denotes a focal length of the self-focusing lens (722), and L denotes a thickness of the self-focusing lens (722).
6. A wavelength selective switch according to claim 5, characterized in that said polarized light beam (9) is reflected by a diffraction grating (721) and re-enters a self-focusing lens (722) to form a combined focal length, said self-focusing lens (722) combined focal length being expressed as:
wherein F represents the combined focal length of the self-focusing lens (722).
7. A wavelength selective switch according to claims 1-6, characterized in that it further comprises a reflective imaging mirror (6), a liquid crystal on silicon device (8); the reflection imaging mirror (6) reflects the polarized light beam (9) into the self-focusing dispersion prism grating (7), the self-focusing dispersion prism grating (7) separates the wavelength of the polarized light beam (9), the self-focusing dispersion prism grating (7) reflects the polarized light beam (9) after wavelength separation into the reflection imaging mirror (6), and the reflection imaging mirror (6) reflects the polarized light beam (9) after wavelength separation into the silicon-based liquid crystal device (8) to form a circular light spot.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310276000.3A CN116466436A (en) | 2023-03-17 | 2023-03-17 | Wavelength selective switch |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310276000.3A CN116466436A (en) | 2023-03-17 | 2023-03-17 | Wavelength selective switch |
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| Publication Number | Publication Date |
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| CN116466436A true CN116466436A (en) | 2023-07-21 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310276000.3A Pending CN116466436A (en) | 2023-03-17 | 2023-03-17 | Wavelength selective switch |
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- 2023-03-17 CN CN202310276000.3A patent/CN116466436A/en active Pending
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