WO2023274317A1 - 波长选择开关 - Google Patents

波长选择开关 Download PDF

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Publication number
WO2023274317A1
WO2023274317A1 PCT/CN2022/102470 CN2022102470W WO2023274317A1 WO 2023274317 A1 WO2023274317 A1 WO 2023274317A1 CN 2022102470 W CN2022102470 W CN 2022102470W WO 2023274317 A1 WO2023274317 A1 WO 2023274317A1
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WO
WIPO (PCT)
Prior art keywords
light
diffraction
diffraction order
wavelength selective
selective switch
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Application number
PCT/CN2022/102470
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English (en)
French (fr)
Inventor
郭正伟
柳贺良
李兆明
丁必锋
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华为技术有限公司
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Publication of WO2023274317A1 publication Critical patent/WO2023274317A1/zh

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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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3534—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being diffractive, i.e. a grating
    • 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
    • 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
    • G02B6/35—Optical coupling means having switching means
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
    • G02B6/3524—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being refractive
    • G02B6/3526—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being refractive the optical element being a lens
    • 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
    • G02B6/35—Optical coupling means having switching means
    • G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/1313—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells specially adapted for a particular application
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems

Definitions

  • the present application relates to the field of optical communication, in particular to a wavelength selective switch.
  • Wavelength selective switch (Wavelength selective switch, WSS) devices are widely used in the field of optical communication, especially in the field of wavelength division optical cross-connect (OXC).
  • the WSS is used to receive an input light, the input light includes light of multiple wavelengths, and the WSS is also used to guide the light of multiple wavelengths to different output ports according to different wavelengths.
  • For each output port it is used to output light of one or more specific wavelengths, the light of one or more specific wavelengths is the signal light of the output port, and the light of other wavelengths is the crosstalk light of the output port.
  • the difference between the insertion loss (Insertion Loss, IL) of the signal light and the crosstalk light is defined as the isolation. Isolation is an important indicator of WSS, how to improve the isolation is a technical problem to be solved urgently.
  • the application provides a wavelength selective switch, including:
  • a light splitting module configured to receive the first light and split the first light to output multiple beams of second light, and the multiple beams of second light have different wavelengths
  • a light diffraction module located on the optical path of the multiple beams of second light, for receiving and diffracting the multiple beams of second light to emit multiple beams of third light
  • the light diffraction module includes a plurality of diffraction areas, the A plurality of diffraction areas correspond to the plurality of beams of second light one by one, and each of the diffraction areas is used to diffract a corresponding beam of second light and emit a beam of third light;
  • An optical transmission module located on the optical path of the multiple beams of third light, the optical transmission module includes a plurality of output channels, each of which is used to receive and output the target diffraction order of at least one beam of third light, each A mode field radius of the output channel is equal to a beam waist radius of the received target diffraction order of the at least one third light;
  • the beam waist radius of the target diffraction order of the at least one third light is different from the beam waist radius of at least one of the other diffraction orders of the at least one third light, or/and the at least one third light
  • the beam waist radius of the target diffraction order of light is different from the beam waist radius of at least one beam of third light among the other third lights.
  • each output channel is used to receive the target diffraction order of at least one beam of third light, and for each output channel, by setting its mode field radius and the target diffraction order of at least one beam of third light it receives
  • the beam waist radii are equal, which can reduce the insertion loss of the signal light of the output channel; by setting its mode field radius and the beam waist radius of at least one diffraction order in the third light received except the target diffraction order Not equal, or/and setting its mode field radius to be unequal to the beam waist radius of at least one of the other third lights may increase the insertion loss of the crosstalk light of the output channel.
  • the beam waist radius of the target diffraction order of the at least one third light is different from the beam waist radius of any one of the other diffraction orders of the at least one third light, or/and the The beam waist radius of the target diffraction order of the at least one third light is different from the beam waist radius of any third light in the other third lights.
  • the wavelength selective switch further includes a plurality of lenses located between the optical diffraction module and the optical transmission module, and the plurality of lenses correspond to the plurality of output channels one by one; each of the The lens is used to receive the target diffraction order of the at least one beam of third light and focus it on the corresponding output channel.
  • the curvature radii of the plurality of lenses are equal.
  • each lens is used to focus the third light to the corresponding output channel, so that the third light can be better coupled to the output channel, and the light energy loss of the third light can be reduced.
  • At least one lens has a different radius of curvature than the other lenses.
  • the beam waist radii of the third light focused by the lenses can be different.
  • the beam waist of the target diffraction order of the third light guided by each lens can be The radius is equal to the mode field radius of the corresponding output channel; and, by setting the radius of curvature of at least one lens different from the radius of curvature of other lenses, the beam waist radius of the target diffraction order of the third light guided by the at least one lens is different
  • the beam waist radius of the other third light that is, the beam waist radius of the other third light is different from the mode field radius of the output channel corresponding to the at least one lens, the above can realize that the third light guided by the at least one lens
  • the mode field of the corresponding output channel is matched, and the other third light is mismatched with the mode field of the corresponding output channel. Therefore, the insertion loss of the signal light can be reduced, the insertion loss of the crosstalk light can
  • the curvature radii of the plurality of lenses are not equal to each other.
  • the beam waist radii of the third light focused by each lens are different, so that the mode field radius of each output channel is different from the beam waist radius of any crosstalk light, which can further increase the insertion of each crosstalk light Loss, which is beneficial to further improve the isolation.
  • the light diffraction module is liquid crystal on silicon, and the beam waist radius of each diffraction order of the plurality of third beams of light can be adjusted respectively by adjusting the driving voltages applied to the plurality of diffraction regions.
  • the beam waist radius of the third light emitted by the light diffraction module will change.
  • the corresponding value can be queried according to the value of the required beam waist radius.
  • the value of the driving voltage is applied to each driving electrode, so that the mode field radius of each output channel is equal to the beam waist radius of the received target diffraction order of the at least one third light, so that the at least The beam waist radius of the target diffraction order of a bundle of third light is different from the beam waist radius of at least one of the other diffraction orders of the at least one third light, or/and the target of the at least one third light
  • the beam waist radius of the diffraction order is different from the beam waist radius of at least one of the other third lights, so as to reduce the insertion loss of the signal light and increase the insertion loss of the crosstalk light, and improve the isolation of the wavelength selective switch.
  • the target diffraction order includes one diffraction order.
  • the target diffraction order is +1 diffraction order.
  • the target diffraction order includes two diffraction orders.
  • the crosstalk between each output channel is reduced, and the wavelength selective switch can be set to realize "double-sided diffraction", thereby improving the integration of the wavelength selective switch.
  • the target diffraction order includes +1 diffraction order and -1 diffraction order.
  • the target diffraction order includes the +1 diffraction order and the -1 diffraction order, which can ensure greater light utilization.
  • the light transmission module further includes an input channel for receiving the first light and transmitting the first light to the light splitting module.
  • both the input of the first light into the WSS and the output of the third light from the WSS are realized through the optical transmission module, which is beneficial to reducing the overall volume of the WSS and simplifying the optical path structure of the WSS.
  • the beam waist radii of the light of each wavelength in the first light are equal.
  • the first light includes light of various wavelengths, since the light of various wavelengths is transmitted in the input channel, in order to reduce the insertion loss of light of various wavelengths in the first light, the light of various wavelengths in the first light.
  • the beam waist radii of the first light are equal, and the beam waist radii of the light of various wavelengths in the first light are equal to the mode field radius of the input channel, thereby improving the utilization rate of the light of various wavelengths in the first light.
  • FIG. 1 is a block diagram of a wavelength selective switch according to Embodiment 1 of the present application.
  • FIG. 2 is a schematic structural diagram of a wavelength selective switch according to Embodiment 1 of the present application.
  • FIG. 3 is a schematic diagram of the process of coupling the third light to the optical transmission module in the wavelength selective switch according to Embodiment 1 of the present application.
  • FIG. 4 is a graph showing the variation of the isolation of the wavelength selective switch in Embodiment 1 of the present application.
  • FIG. 5 is a schematic diagram of the process of coupling the third light to the optical transmission module in the wavelength selective switch according to the second embodiment of the present application.
  • FIG. 6 is a schematic diagram of the process of coupling the third light to the optical transmission module in the wavelength selective switch according to the third embodiment of the present application.
  • the wavelength selective switch is applied in the optical communication system, and is used to guide the received mixed wavelength light to different output channels according to different wavelengths.
  • the wavelength selective switch 100 of this embodiment includes a light splitting module 10 , a light diffraction module 20 and a light transmission module 30 .
  • the light splitting module 10 is used for receiving the first light L1 and splitting the first light L1 into multiple beams of second light L2 to emit.
  • the light diffraction module 20 is used for receiving multiple beams of second light L2 and for outputting multiple beams of third light L3 after diffracting the multiple beams of second light L2 respectively.
  • the light transmission module 30 is used for receiving multiple beams of third light L3 and outputting multiple beams of third light L3 from multiple output channels.
  • the first light L1 , the second light L2 and the third light L3 are all Gaussian beams.
  • the first light L1 includes lights of various wavelengths.
  • the first light L1 is output by a light source (such as a laser) or an optical device (such as an optical fiber) outside the wavelength selective switch 100 .
  • the light splitting module 10 is a diffraction grating.
  • the light splitting module 10 is used for receiving the first light L1 and diffracting it to emit multiple beams of second light L2.
  • Each beam of second light L2 has a different wavelength. Based on the orientation in Figure 2, define the horizontal direction as the X direction and the vertical direction as the Y direction.
  • Multiple beams of second light L2 emitted by the light splitting module 10 are arranged sequentially along the X direction.
  • the light splitting module 10 is used to emit N beams of second light L2.
  • the wavelengths of the second light L2 arranged from left to right along the X direction are denoted as ⁇ 1 , ⁇ 2 , ⁇ 3 . . . ⁇ n in sequence.
  • the light diffraction module 20 is liquid crystal on silicon.
  • the light diffraction module 20 is located on the optical path of the multiple beams of second light L2 for receiving the second light L2 and diffracting the multiple beams of second light L2. Due to the birefringence effect of the liquid crystal, by applying a specific voltage to the light diffraction module 20 , multiple beams of second light L2 are diffracted by the light diffraction module 20 .
  • the diffracted light emitted from the light diffraction module 20 is defined as the third light L3.
  • the light diffraction module 20 After the second light L2 of different wavelengths enters the light diffraction module 20, it is diffracted in different directions by the light diffraction module 20, so that each beam of third light L3 is guided to different output ports in the light transmission module 30, so as to achieve The purpose of wavelength splitting (that is, making the third light L3 of a specific wavelength output from a specific output channel).
  • the light diffraction module 20 may also be a micro-electro-mechanical system (Micro-Electro-Mechanical System, MEMS) or the like.
  • the light diffraction module 20 includes a plurality of diffraction regions 21 .
  • each diffraction area 21 is rectangular, and a plurality of diffraction areas 21 are arranged parallel to each other.
  • the plurality of diffraction areas 21 correspond to the plurality of beams of second light L2 one by one, and each diffraction area 21 is used to receive and diffract a corresponding beam of second light L2 to emit a corresponding third light L3. That is to say, the light diffraction module 20 includes N diffraction areas 21 , and with reference to FIG. 2 , the N diffraction areas 21 are numbered 1, 2, 3 . . . N from left to right.
  • the diffraction area 21 numbered 1 is used to receive and diffract the second light L2 with a wavelength of ⁇ 1
  • the diffraction area 21 numbered 2 is used to receive and diffract the second light L2 with a wavelength ⁇ 2
  • the diffraction area 21 numbered 3 is used for To receive and diffract the second light L2 with a wavelength of ⁇ 3
  • the diffraction area 21 numbered N is used to receive and diffract the second light L2 with a wavelength of ⁇ n.
  • the light diffraction module 20 includes a plurality of driving electrodes 22 electrically insulated from each other.
  • a plurality of driving electrodes 22 are arranged in an array including multiple rows (X direction) and multiple columns (Y direction), the number of driving electrodes 22 in each row is equal, and the number of driving electrodes 22 in each column is equal.
  • multiple rows of driving electrodes 22 are arranged in each diffractive region 21 .
  • the respective drive electrodes 22 receive drive voltages independently of each other.
  • the angle of the third light L3 emitted by each diffraction area 21 can be controlled, that is, the output of the third light L3 of each diffraction area 21 can be controlled.
  • Directions, so that multiple beams of third light L3 are respectively guided to corresponding output channels in the light transmission module 30 through the multiple diffraction regions 21 .
  • the optical transmission module 30 includes a plurality of output channels 31 , and each output channel 31 is an optical fiber.
  • a plurality of output channels 31 are arranged along the Y direction. That is, in this embodiment, the arrangement of the plurality of output channels 31 is anti-perpendicular to the arrangement direction of the plurality of diffraction regions 21 .
  • Each output channel 31 is used to receive at least one third light L3. That is, the multiple output channels 31 are not in one-to-one correspondence with the multiple beams of third light L3. As for an output channel 31, it may be used to receive one or more beams of third light L3.
  • the quantity of the third light L3 received by each output channel 31 and the wavelength of the third light L3 received by each output channel 31 are determined according to the optical path after the output channel 31 outputs the third light L3.
  • the present application does not limit the quantity and wavelength of the third light L3 received by each output channel 31 .
  • Each third light L3 has a plurality of diffraction orders: -M...-3, -2, -1, 0, +1, +2, +3...+M orders.
  • the horizontal axis represents each diffraction order at each diffraction angle
  • the vertical axis represents the light intensity I of each diffraction order.
  • Each output channel 31 is used to receive one of the diffraction orders of the third light L3.
  • the diffraction order received by the output channel 31 is defined as the target diffraction order. Since the light intensity of the +1 diffraction order is the highest, in order to ensure a greater light utilization rate, in this embodiment, multiple output channels 31 are used to receive and output the +1 diffraction order of multiple beams of third light L3.
  • the target diffraction order of the plurality of output channels 31 is the +1 diffraction order.
  • the target diffraction order can also be the +2 diffraction order, etc., and the light intensity of the +2 diffraction order can be adjusted to reach the light intensity of the +1 diffraction order by setting the diffraction angle, or slightly smaller than the +1 diffraction order High light intensity to ensure maximum light utilization.
  • the present application does not set any special limitation on the selection of the target diffraction order.
  • the output channel 311 is used to receive the +1 diffraction order of the third light L3 with a wavelength of ⁇ 1, then for the output channel 311, the +1 diffraction order of the third light L3 with a wavelength of ⁇ 1 is the output channel 311 signal light, and other diffraction orders of the third light L3 with a wavelength of ⁇ 1 and the third light L3 with other wavelengths are all crosstalk lights of the output channel 311 .
  • the division of the signal light and the crosstalk light of the other output channels 31 is the same and will not be repeated here.
  • both the signal light and the crosstalk light have an insertion loss (Insertion Loss, IL) when they are incident on the output channel 31.
  • IL Insertion Loss
  • the difference between the insertion loss of the signal light and the crosstalk light is defined as the isolation. The higher the isolation, the better the performance of the wavelength selective switch 100 .
  • the isolation is improved by reducing the insertion loss of the signal light.
  • the mode field radius of each output channel 31 is set equal to the beam waist radius of the target diffraction order of the third light L3 received by it. That is, making each output channel 31 match the mode field of the target diffraction order of the third light L3 received by it can help reduce the insertion loss of the signal light.
  • the output channel 311 is used to receive the +1 diffraction order of the third light L3 whose wavelength is ⁇ 1, and the mode field radius of the output channel 311 is set to the +1 diffraction order of the third light L3 whose wavelength is ⁇ 1
  • the beam waist radii are equal, so that the output channel 311 matches the mode field of the +1 diffraction order of the third light L3 with a wavelength of ⁇ 1, thereby reducing the time when the +1 diffraction order of the third light L3 with a wavelength of ⁇ 1 is coupled to the output channel 311 insertion loss.
  • the isolation is improved by increasing the insertion loss of the crosstalk light.
  • the mode field radius of each output channel 31 is set to be different from the beam waist radius of at least one crosstalk light (the crosstalk light with different wavelengths is considered to be different kinds of crosstalk light, and the light with different diffraction orders Also considered a different kind of crosstalk light).
  • setting the mode field radius of the output channel 311 to be different from the beam waist radius of at least one crosstalk light can make the output channel 311 mismatch with the mode field of at least one crosstalk light, thereby increasing at least one
  • the insertion loss of the crosstalk light entering the output channel 311 means that it is difficult for the crosstalk light to enter the output channel 311 .
  • the mode field radius of each output channel 31 is set to be different from the beam waist radius of the third light L3 received by the output channel 31 arranged adjacent to it, or/and each output channel 31 is set
  • the mode field radius of is different from the beam waist radius of the diffraction orders other than the target diffraction order in the third light L3 received by it.
  • the closer crosstalk light is the third light L3 received by the adjacently arranged output channel 31 and the third light L3 received by itself, except for the target diffraction order. Therefore, in this modified embodiment, by setting the mode field radius of each output channel 31 to be different from the beam waist radius of the third light L3 received by the output channel 31 adjacent to it, or/and setting the mode field radius of each output channel 31 The field radius is different from the beam waist radius of the diffraction orders other than the target diffraction order in the received third light L3, which is beneficial to efficiently improve the isolation.
  • the mode field radius of each output channel 31 is different from the beam waist radius of any crosstalk light, which can increase the insertion loss of each crosstalk light, thereby further improving the isolation.
  • the wavelength selective switch 100 of this embodiment for each output channel 31, by reducing the insertion loss of the signal light and increasing the insertion loss of the crosstalk light, it is beneficial to improve the isolation, and the performance of the wavelength selective switch 100 can be effectively improved. .
  • the beam waist radius of the signal light and the beam waist radius of the crosstalk light are adjusted by adjusting the voltage applied to each driving electrode 22, so that the signal light matches the mode field of the output channel 31, and the crosstalk light matches the output channel 31.
  • Channel 31 Mode Field Mismatch is adjusted by adjusting the voltage applied to each driving electrode 22, so that the signal light matches the mode field of the output channel 31, and the crosstalk light matches the output channel 31.
  • the beam waist radius of the third light L3 emitted by the light diffraction module 20 will change.
  • the corresponding relationship between the value of the driving voltage and the value of the beam waist radius can be stored as a look-up table through pre-experiment or pre-calculated according to an algorithm, so that during the working process of the wavelength selective switch 100, the required beam waist radius can be The value looks up the value of the corresponding drive voltage and is applied to each drive electrode 22 .
  • ⁇ represents the degree of isolation
  • ⁇ 1 and ⁇ 2 represent the beam waist radius of the third light L3 and the mode field radius of the output channel 31, respectively.
  • the variation curve of the isolation degree ⁇ with the value of the other can be obtained.
  • Fig. 4 shows that when one of ⁇ 1 and ⁇ 2 has a value of 40 ⁇ m, the variation curve of the isolation degree ⁇ with the value of the other.
  • the horizontal axis represents the value of the aforementioned "other”
  • the vertical axis represents the isolation degree ⁇ .
  • the optical transmission module 30 further includes an input channel 32 .
  • the input channel 32 is also an optical fiber.
  • the input channel 32 is used for receiving the first light L1 and transmitting the first light L1 to the light splitting module 10 . That is, in this embodiment, the input of the first light L1 to the wavelength selective switch 100 and the output of the third light L3 from the wavelength selective switch 100 are realized through the optical transmission module 30, which is beneficial to reduce the overall volume of the wavelength selective switch 100 and simplify the wavelength. Select the optical path structure of the switch 100 .
  • the first light L1 includes light of various wavelengths. Since the light of various wavelengths is transmitted in the input channel 32, in order to reduce the insertion loss of light of various wavelengths in the first light L1, the first light The beam waist radii of the light of various wavelengths in L1 are equal, and the beam waist radii of the light of various wavelengths in the first light L1 are equal to the mode field radius of the input channel 32, thereby improving the light of various wavelengths in the first light L1 utilization rate.
  • the input channel 32 and the output channel 31 are all optical transmission channels, which are basically the same in structure. According to the light output direction, in other embodiments, the input channel 32 can also be used as the output channel 31, and the output channel 31 can also be used as input channel 32.
  • An optical transmission channel is specifically an input channel or an output channel, depending on the direction in which the optical transmission channel transmits light.
  • the wavelength selective switch 100 further includes a plurality of lenses 40 .
  • the multiple lenses 40 correspond to the multiple output channels 31 one by one.
  • Each lens 40 is located between an output channel 31 and the light diffraction module 20 .
  • the curvature radii of the lenses 40 are the same.
  • Each lens 40 is used to focus the third light L3 to the corresponding output channel 31 . In order to make the third light L3 be better coupled to the output channel 31 and reduce the light energy loss of the third light L3.
  • the wavelength selective switch 100 may also include other necessary components, such as a polarizer for converting the first light L1 into linearly polarized light, a polarizer for guiding the first light L1, the second light L2, and the third light.
  • L3 transmits light guiding elements (such as reflectors, cylindrical lenses), etc.
  • This application mainly introduces the elements related to this application. Other components will not be described in detail.
  • the number of element structures shown in the accompanying drawings of this embodiment is not used to limit the present application, for example, the number of driving electrodes 22 in each diffraction area 21 shown in FIG. 2 , or the output channel 31 and Enter the number of channels 32, etc.
  • the quantity of the above-mentioned components can be different in different embodiments, and the drawings are only examples.
  • each output channel 31 is used to receive the target diffraction order of at least one beam of third light L3.
  • the beam waist radius of the target diffraction order of the three light L3 is equal, which can reduce the insertion loss of the signal light of the output channel 31; by setting its mode field radius and other diffractions except the target diffraction order in the third light L3 received
  • the beam waist radius of at least one diffraction order in the order is not equal, or/and setting its mode field radius is not equal to the beam waist radius of at least one third light L3 in the other third light L3, which can increase the crosstalk light of the output channel 31 insertion loss.
  • the difference between the wavelength selective switch of this embodiment and the wavelength selective switch 100 in the first embodiment mainly lies in the way of adjusting the beam waist radius of the third light L3 .
  • the method of adjusting the beam waist radius of the third light L3 by adjusting the radius of curvature of each lens 40 replaces the method of adjusting the beam waist radius of the third light L3 by adjusting the driving voltage on the driving electrode 22 in the first embodiment.
  • the effect of the light diffraction module 20 on the second light L2 can be equivalent to a lens. Therefore, in the first embodiment, adjusting the driving voltage on each driving electrode 22 can also be regarded as equivalent to adjusting the radius of curvature of a lens.
  • the beam waist radii of the third light L3 focused by the lenses 40 may be different.
  • the beam waist radius of the target diffraction order of the third light guided by each lens 40 is equal to the mode field radius of the corresponding output channel 31 .
  • the beam waist radius of the target diffraction order of the third light L3 guided by the at least one lens 40 is different from the beam of other third light L3
  • the waist radius means that the beam waist radius of the other third light L3 is different from the mode field radius of the output channel 31 corresponding to the at least one lens 40 .
  • the radii of curvature of the plurality of lenses 40 are not equal to each other, so that the beam waist radii of the third light L3 focused by each lens 40 are not equal, so that the mode field of each output channel 31
  • the radius is different from the beam waist radius of any crosstalk light, which can further increase the insertion loss of each crosstalk light, thereby helping to further improve the isolation.
  • the wavelength selective switch of this embodiment can realize all the beneficial effects of the wavelength selective switch 100 in the first embodiment. On this basis, this embodiment also provides a technical solution of adjusting the curvature radii of the multiple lenses 40 instead of adjusting the driving voltage on the multiple driving electrodes 22 .
  • the driving voltage applied to each driving electrode 22 can be adjusted at the same time to realize the beam waist of the signal light of each output channel 31
  • the adjustment of the radius and the beam waist radius of the crosstalk light that is, realize the adjustment of the beam waist radius of each third light L3), so that the signal light matches the mode field of the output channel 31, and the crosstalk light matches the mode field of the output channel 31 Mismatch, improve isolation from these two aspects.
  • the principle of coherence and cancellation and the principle of radial mismatch are also used to further improve the isolation of the wavelength selective switch.
  • each output channel 31 is used to receive the +1 diffraction order of one or more beams of third light L3, and by adjusting the driving voltage on each driving electrode 22, the third light L3 can be adjusted.
  • the phases of other diffraction orders so that the other diffraction orders in each third light L3 except the +1 diffraction order at least partially cancel each other, reducing the coupling of the diffraction orders in the third light L3 except the +1 diffraction order to the output channel 31 amount. That is, the crosstalk light is reduced through the coherent and destructive manner, and the insertion loss of the crosstalk light is increased, which is beneficial to improving the isolation.
  • the radial mismatch it can be realized by increasing the distance between the output channels 31 .
  • the above-mentioned another modified embodiment is also beneficial to further improving the isolation of the wavelength selective switch.
  • the difference between the wavelength selective switch in this embodiment and the wavelength selective switch in the first embodiment mainly lies in that the arrangement of the output channel 31 and the input channel 32 is different.
  • the optical transmission module 30 includes a plurality of output channels 31 and an input channel 32 .
  • the input channel 32 and the plurality of output channels 31 are arranged in parallel, and the input channel is located on the same side of the plurality of output channels 31 . That is, in the first embodiment, the light transmission module 30 includes a plurality of light transmission channels arranged in parallel, wherein the leftmost or rightmost light transmission channel is used as the light input channel 32 .
  • the input channel 32 and the plurality of output channels 31 are arranged in parallel, and the plurality of output channels 31 are respectively located on both sides of the input channel 32 . That is to say, taking the orientation of FIG. 6 as a reference, in this embodiment, part of the output channel 31 is located on the left side of the input channel 32, and another part of the output channel 31 is located on the right side of the input channel 32. And in this embodiment, the number of output channels 31 located on the left and right of the input channel 32 is equal. In a modified embodiment of this embodiment, the number of output channels 31 on the left and right of the input channel 32 may be different.
  • the wavelength selective switch in this embodiment can realize all the beneficial effects of the wavelength selective switch 100 in the embodiment, so the isolation of the wavelength selective switch in this embodiment is effectively improved.
  • the crosstalk between the output channels 31 is reduced, and the wavelength selective switch in this embodiment can be set to realize "double-sided diffraction".
  • a plurality of output channels 31 are respectively located on both sides of the input channel 32, and the third light L3 is output from the output channels 31 on both sides of the input channel 32, and in this embodiment, the target diffraction order includes two Diffraction order: +1 diffraction order and -1 diffraction order, the +1 diffraction order and -1 diffraction order are respectively output from the output channels 31 on the left and right sides of the input channel 32 .
  • the wavelength selective switch of this embodiment adopts the above-mentioned "double-sided diffraction", so that the distance between the multiple output channels 31 and the input channels 32 can be effectively reduced, which is beneficial to improve the integration of the wavelength selective switch.
  • the arrangement of the input channel 32 and the multiple output channels 31 can also be applied to the second embodiment, and the same technical effect can also be achieved.

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Abstract

一种波长选择开关（100），包括：分光模块（10），用于对第一光进行分束，以输出多束第二光；光衍射模块（20），用于接收并衍射多束第二光，以出射多束第三光，包括多个衍射区（21），每一衍射区（21）用于衍射所对应的一束第二光并出射一束第三光；光传输模块（30），位于多束第三光的光路上，光传输模块（30）包括多个输出通道（31），每一输出通道（31）用于接收并输出至少一束第三光的目标衍射级，每一输出通道（31）的模场半径与所接收的至少一束第三光的目标衍射级的束腰半径相等；至少一束第三光的目标衍射级的束腰半径不同于至少一束第三光的其它衍射级中至少一个衍射级的束腰半径，或/和至少一束第三光的目标衍射级的束腰半径不同于其它第三光中至少一束第三光的束腰半径。

Description

波长选择开关
相关申请的交叉引用
本申请要求在2021年7月02日提交中国专利局、申请号为202110751349.9、申请名称为“波长选择开关”的中国专利的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及光通信领域，尤其涉及一种波长选择开关。
背景技术
波长选择开关(Wavelength selective switch,WSS)器件被广泛应用于光通信领域特别是波分光交叉(Optical cross-connect,OXC)领域中。WSS用于接收一输入光，该输入光中包括多个波长的光，WSS还用于将该多个波长的光按照波长不同而分别引导至不同的输出端口。对于每一输出端口，其用于输出一个或多个特定波长的光，该一个或多个特定波长的光为该输出端口的信号光，其它波长的光为该输出端口的串扰光。信号光与串扰光的插入损耗(Insertion Loss,IL)之差定义为隔离度。隔离度为WSS的一个重要指标，如何提高隔离度为亟待解决的技术问题。
发明内容
本申请提供一种波长选择开关，包括：
分光模块，用于接收第一光并对所述第一光进行分束，以输出多束第二光，所述多束第二光具有不同的波长；
光衍射模块，位于所述多束第二光的光路上，用于接收并衍射所述多束第二光，以出射多束第三光，所述光衍射模块包括多个衍射区，所述多个衍射区与所述多束第二光一一对应，每一所述衍射区用于衍射所对应的一束第二光并出射一束所述第三光；以及
光传输模块，位于所述多束第三光的光路上，所述光传输模块包括多个输出通道，每一所述输出通道用于接收至少一束第三光的目标衍射级并输出，每一所述输出通道的模场半径与所接收的所述至少一束第三光的目标衍射级的束腰半径相等；
所述至少一束第三光的目标衍射级的束腰半径不同于所述至少一束第三光的其它衍射级中至少一个衍射级的束腰半径，或/和所述至少一束第三光的目标衍射级的束腰半径不同于其它第三光中至少一束第三光的束腰半径。
上述波长选择开关，每一输出通道用于接收至少一束第三光的目标衍射级，对于每一输出通道，通过设置其模场半径与其所接收的至少一束第三光的目标衍射级的束腰半径相等，可减小输出通道的信号光的插入损耗；通过设置其模场半径与其所接收的第三光中除目标衍射级之外的其它衍射级中至少一衍射级的束腰半径不相等，或/和设置其模场半径与其它第三光中至少一束第三光的束腰半径不相等，可增加输出通道的串扰光的插入损耗。通过减小输出通道的信号光的插入损耗和增加输出通道的串扰光的插入损耗，可提升波长选择开关的隔离度。
于一些实施例中，所述至少一束第三光的目标衍射级的束腰半径不同于所述至少一束第三光的其它衍射级中任意一个衍射级的束腰半径，或/和所述至少一束第三光的目标衍射级的束腰半径不同于其它第三光中任意一束第三光的束腰半径。
如此，可增大每种串扰光的插入损耗，从而有利于进一步提升隔离度。
于一些实施例中，波长选择开关还包括位于所述光衍射模块和所述光传输模块之间的多个透镜，所述多个透镜与所述多个输出通道一一对应；每一所述透镜用于接收所述至少一束第三光的目标衍射级并聚焦至所对应的所述输出通道。
于一些实施例中，所述多个透镜的曲率半径相等。
如此，每一透镜用于聚焦第三光至相应的输出通道，以使得第三光更好地耦合至输出通道，减少第三光的光能损失。
于一些实施例中，至少一个透镜的曲率半径不同于其它透镜的曲率半径。
如此，透镜的曲率半径不同时，可使得透镜所聚焦的第三光的束腰半径不同，通过设置每一透镜的曲率半径，使得每一透镜所引导的第三光的目标衍射级的束腰半径于对应的输出通道的模场半径相等；并且，通过设置至少一透镜的曲率半径不同于其它透镜的曲率半径，使得该至少一个透镜所引导的第三光的目标衍射级的束腰半径不同于其它第三光的束腰半径，也即使得其它第三光的束腰半径不同于该至少一个透镜所对应的输出通道的模场半径，上述可实现该至少一个透镜所引导的第三光与对应的输出通道模场匹配，且实现其它第三光与该对应的输出通道模场失配，因此可实现减少信号光的插入损耗且增大串扰光的插入损耗，提升隔离度。
于一些实施例中，所述多个透镜的曲率半径互不相等。
如此，使得各个透镜所聚焦的第三光的束腰半径各不相等，从而每一输出通道的模场半径不同于任意一种串扰光的束腰半径，可进一步增大每种串扰光的插入损耗，从而有利于进一步提升隔离度。
于一些实施例中，所述光衍射模块为硅基液晶，通过分别调节施加至所述多个衍射区的驱动电压，分别调节所述多束第三光的各个衍射级的束腰半径。
如此，当施加至驱动电极上的驱动电压改变时，光衍射模块出射的第三光的束腰半径会发生变化，在波长选择开关工作过程中，可根据所需的束腰半径的值查询相应的驱动电压的值并施加至各个驱动电极，以使得每一所述输出通道的模场半径与所接收的所述至少一束第三光的目标衍射级的束腰半径相等，使得所述至少一束第三光的目标衍射级的束腰半径不同于所述至少一束第三光的其它衍射级中至少一个衍射级的束腰半径，或/和所述至少一束第三光的目标衍射级的束腰半径不同于其它第三光中至少一束第三光的束腰半径，从而实现减小信号光的插入损耗并增加串扰光的插入损耗，提升波长选择开关的隔离度。
于一些实施例中，所述目标衍射级包括一个衍射级。
于一些实施例中，所述目标衍射级为+1衍射级。
如此，由于+1衍射级的光强度最大，目标衍射级为+1衍射级，可保证较大的光利用率。
于一些实施例中，所述目标衍射级包括两个衍射级。
在波长选择开关的隔离度提升的基础上，各个输出通道之间的串扰被减小，可设置波长选择开关实现“双边衍射”，从而提升波长选择开关的集成度。
于一些实施例中，所述目标衍射级包括+1衍射级和-1衍射级。
如此，由于+1衍射级和-1衍射级的光强度最大，目标衍射级包括+1衍射级和-1衍射级， 可保证较大的光利用率。
于一些实施例中，所述光传输模块还包括一输入通道，所述输入通道用于接收所述第一光并传输所述第一光至所述分光模块。
如此，第一光输入波长选择开关和第三光从波长选择开关输出都通过光传输模块实现，有利于减小波长选择开关的整体体积，简化波长选择开关的光路结构。
于一些实施例中，所述第一光中各个波长的光的束腰半径相等。
如此，第一光中包括多种波长的光，由于多种波长的光都在输入通道中传输，为了降低第一光中各种波长的光的插入损耗，第一光中各种波长的光的束腰半径相等，且第一光中各种波长的光的束腰半径与输入通道的模场半径相等，从而提升第一光中各种波长的光的利用率。
附图说明
图1为本申请实施例一的波长选择开关的模块结构图。
图2为本申请实施例一的波长选择开关的结构示意图。
图3为本申请实施例一的波长选择开关中第三光耦合至光传输模块的过程示意图。
图4为本申请实施例一中波长选择开关的隔离度变化曲线图。
图5为本申请实施例二的波长选择开关中第三光耦合至光传输模块的过程示意图。
图6为本申请实施例三的波长选择开关中第三光耦合至光传输模块的过程示意图。
具体实施方式
下面结合本申请实施例中的附图对本申请实施例进行描述。
实施例一
波长选择开关应用于光通信系统中，用于将接收到的混合波长的光根据波长不同而引导至不同的输出通道。
请参阅图1，本实施例的波长选择开关100，包括分光模块10、光衍射模块20及光传输模块30。分光模块10用于接收第一光L1并将第一光L1分成多束第二光L2出射。光衍射模块20用于接收多束第二光L2并用于将多束第二光L2分别衍射后输出多束第三光L3。光传输模块30用于接收多束第三光L3并将多束第三光L3从多个输出通道输出。
本实施例中，第一光L1、第二光L2、第三光L3皆为高斯光束。第一光L1包括多种波长的光。第一光L1由波长选择开关100外部的光源(例如激光器)或光学器件(例如光纤)输出。请参阅图2，本实施例中，分光模块10为衍射光栅。分光模块10用于接收第一光L1并对其进行衍射以出射多束第二光L2。每一束第二光L2具有不同的波长。以图2方位为基准，定义水平方向为X方向，垂直方向为Y方向。分光模块10出射的多束第二光L2沿X方向依次排列。本实施例中，分光模块10用于出射N束第二光L2。以图2为基准，沿X方向从左到右依次排列的第二光L2的波长依次表示为λ1、λ2、λ3……λn。
本实施例中，光衍射模块20为硅基液晶。光衍射模块20位于多束第二光L2的光路上，用于接收第二光L2并将多束第二光L2衍射。因液晶的双折射效应，通过对光衍射模块20施加特定的电压，使得多束第二光L2被光衍射模块20衍射。定义从光衍射模块20出射的衍射后的光为第三光L3。不同波长的第二光L2入射至光衍射模块20之后，被光衍射模块20以不同的方向衍射，从而使得各束第三光L3被引导至光传输模块30中不同的输出端口，以达 到根据波长分光(也即使得特定波长的第三光L3从特定的输出通道输出)的目的。于其它实施例中，光衍射模块20也可为微机电系统(Micro-Electro-Mechanical System，MEMS)等。
光衍射模块20包括多个衍射区21。本实施例中，每一衍射区21为矩形，多个衍射区21相互平行排列。多个衍射区21与多束第二光L2一一对应，每一衍射区21用于接收并衍射其所对应的一束第二光L2，以对应出射一第三光L3。也即，光衍射模块20包括N个衍射区21，以图2为基准，N个衍射区21从左至右依次编号为1、2、3……N。编号为1的衍射区21用于接收并衍射波长为λ1的第二光L2，编号为2的衍射区21用于接收并衍射波长为λ2的第二光L2，编号为3的衍射区21用于接收并衍射波长为λ3的第二光L2，编号为N的衍射区21用于接收并衍射波长为λn的第二光L2。
光衍射模块20包括多个相互电绝缘的驱动电极22。多个驱动电极22排列为包括多行(X方向)多列(Y方向)的阵列，每行的驱动电极22数量相等，每列的驱动电极22数量相等。本实施例中，每一衍射区21内排列有多列驱动电极22。各个驱动电极22相互独立地接收驱动电压。通过控制每一衍射区21内的多列驱动电极22上的驱动电压，可控制每一衍射区21出射的第三光L3的角度，也即控制每一衍射区21的第三光L3的出射方向，从而分别通过多个衍射区21将多束第三光L3分别引导至光传输模块30中相应的输出通道。
请参阅图3，本实施例中，光传输模块30包括多个输出通道31，每一输出通道31为光纤。多个输出通道31沿Y方向排列。也即，本实施例中，多个输出通道31的排列反向垂直于多个衍射区21的排列方向。每一输出通道31用于接收至少一第三光L3。也即，多个输出通道31于多束第三光L3并非是一一对应的。对于一输出通道31，其可能用于接收一束或多束第三光L3。每一输出通道31所接收的第三光L3的数量、每一输出通道31所接收的第三光L3的波长根据输出通道31输出第三光L3后的光路决定。本申请不限定各个输出通道31接收第三光L3的数量和波长。
每一第三光L3具有多个衍射级次:-M……-3,-2,-1,0,+1,+2,+3……+M级。图3中横轴表示各个衍射角处的各个衍射级，纵轴表示各个衍射级的光强度I。每一输出通道31用于接收第三光L3的其中一个衍射级。定义输出通道31所接收的衍射级为目标衍射级。由于+1衍射级的光强度最大，为了保证较大的光利用率，本实施例中，多个输出通道31用于接收并输出多束第三光L3的+1衍射级。也即，本实施例中，多个输出通道31的目标衍射级为+1衍射级。于其他实施例中，目标衍射级也可以为+2衍射级等，且可通过设置衍射角等方式调节+2衍射级的光强达到+1衍射级的光强，或稍小于+1衍射级的光强，以保证较大的光利用率。本申请不对目标衍射级的选取作特别限定。
以输出通道311为例，例如输出通道311用于接收波长为λ1的第三光L3的+1衍射级，则对于输出通道311，波长为λ1的第三光L3的+1衍射级为输出通道311的信号光，而波长为λ1的第三光L3的其它衍射级和其它波长的第三光L3都是输出通道311的串扰光。其它输出通道31的信号光于串扰光的划分同理，不再赘述。
为了提高波长选择开关100的性能，对于每一输出通道31，应尽可能多地接收信号光并尽可能避免接收到串扰光。而信号光和串扰光入射到输出通道31时都存在插入损耗(Insertion Loss,IL)，插入损耗越大，表示入射时光能损耗越多，则信号光的插入损耗越小且串扰光的插入损耗越大越有利于提升波长选择开关100的性能。信号光与串扰光的插入损耗之差定义为隔离度。隔离度越高则波长选择开关100的性能越好。
因此，本实施例中，从以下两方面提升隔离度：
第一方面，通过减小信号光的插入损耗提升隔离度。
为了减小信号光的插入损耗，设置每一输出通道31的模场半径与其所接收的第三光L3的目标衍射级的束腰半径相等。也即使得每一输出通道31与其所接收的第三光L3的目标衍射级模场匹配，即可有利于减小信号光的插入损耗。以输出通道311为例，输出通道311用于接收波长为λ1的第三光L3的+1衍射级，设置输出通道311的模场半径与波长为λ1的第三光L3的+1衍射级的束腰半径相等，使得输出通道311与波长为λ1的第三光L3的+1衍射级的模场匹配，从而减小波长为λ1的第三光L3的+1衍射级耦合至输出通道311时的插入损耗。
第二方面，通过增大串扰光的插入损耗提升隔离度。
为了增大串扰光的插入损耗，设置每一输出通道31的模场半径不同于至少一种串扰光的束腰半径(波长不同的串扰光被认为是不同种类的串扰光、衍射级不同的光也被认为是不同种类的串扰光)。
以输出通道311为例，设置输出通道311的模场半径不同于至少一种串扰光的束腰半径，可使得输出通道311与其至少一种串扰光的模场失配，从而增大至少一种串扰光入射到输出通道311的插入损耗，也即使得串扰光难以入射至输出通道311。
于本申请一变更实施例中，设置每一输出通道31的模场半径不同于与其相邻排列的输出通道31所接收的第三光L3的束腰半径，或/和设置每一输出通道31的模场半径不同于其接收的第三光L3中除所述目标衍射级之外的衍射级的束腰半径。对于每一输出通道31，更容易接收到距离较近的串扰光而不容易接收到距离较远的串扰光。因此增加距离较近的串扰光的插入损耗更有利于高效地提升隔离度。对于每一输出通道31，距离较近的串扰光为相邻排列的输出通道31所接收的第三光L3和本身所接收的第三光L3中除所述目标衍射级之外的衍射级。因此本变更实施例，通过设置每一输出通道31的模场半径不同于与其相邻排列的输出通道31所接收的第三光L3的束腰半径，或/和设置每一输出通道31的模场半径不同于其接收的第三光L3中除所述目标衍射级之外的衍射级的束腰半径，有利于高效提升隔离度。
于本申请另一变更实施例中，每一输出通道31的模场半径不同于任意一种串扰光的束腰半径，可增大每种串扰光的插入损耗，从而有利于进一步提升隔离度。
因此，本实施例的波长选择开关100，对于每一输出通道31，通过减小信号光的插入损耗并且增大串扰光的插入损耗，有利于提升隔离度，可有效提升波长选择开关100的性能。
对于每一输出通道31，其模场半径取决于光纤的材料、结构，因此输出通道一旦制成，其模场半径是不可变的。本实施例中，通过调节施加至各个驱动电极22上的电压来调节信号光的束腰半径和串扰光的束腰半径，以使得信号光与输出通道31模场匹配，且使得串扰光与输出通道31模场失配。
当施加至各个驱动电极22上的驱动电压改变时，光衍射模块20出射的第三光L3的束腰半径会发生变化。驱动电压的值与束腰半径的值之间的对应关系可通过预先实验或预先根据算法计算后存储为一查找表，从而在波长选择开关100工作过程中，可根据所需的束腰半径的值查询相应的驱动电压的值并施加至各个驱动电极22。
以η表示隔离度，ω1和ω2分别表示第三光L3的束腰半径和输出通道31的模场半径。满足如下公式：
Figure PCTCN2022102470-appb-000001
将ω1和ω2中其中一者取定值，可得到隔离度η随另一者的值的变化曲线。例如，图4所示为当ω1和ω2中其中一者的值为40微米时，隔离度η 随另一者的值的变化曲线。图4中横轴为前述的“另一者”的值，纵轴为隔离度η。由图4可知，若ω1和ω2中其中一者的值被设定为40微米，另一者的值也为40微米时，隔离度η最小，另一者的值偏离40微米时，隔离度η增大。另一者的值偏离40微米越多，隔离度η增大越多。由此可知，通过设置第三光L3的束腰半径和输出通道31的模场半径相等，可提升隔离度。
请再参阅图3，本实施例中，光传输模块30还包括一输入通道32。输入通道32也为光纤。输入通道32用于接收第一光L1并将第一光L1传输至分光模块10。也即，本实施例中，第一光L1输入波长选择开关100和第三光L3从波长选择开关100输出都通过光传输模块30实现，有利于减小波长选择开关100的整体体积，简化波长选择开关100的光路结构。
本实施例中，第一光L1中包括多种波长的光，由于多种波长的光都在输入通道32中传输，为了降低第一光L1中各种波长的光的插入损耗，第一光L1中各种波长的光的束腰半径相等，且第一光L1中各种波长的光的束腰半径与输入通道32的模场半径相等，从而提升第一光L1中各种波长的光的利用率。
对于光传输模块30，输入通道32和输出通道31都是光传输通道，本身在结构上基本相同，根据光输出方向不同，在其它实施例中，输入通道32也可作为输出通道31，输出通道31也可作为输入通道32。一个光传输通道具体为输入通道或输出通道，取决于光传输通道传输光的方向。
本实施例中，波长选择开关100还包括多个透镜40。多个透镜40与多个输出通道31一一对应。每一透镜40位于一输出通道31与光衍射模块20之间。本实施例中，各个透镜40的曲率半径相同。每一透镜40用于聚焦第三光L3至相应的输出通道31。以使得第三光L3更好地耦合至输出通道31，减少第三光L3的光能损失。
本实施例中，波长选择开关100还可包括其它必要的元件，例如用于将第一光L1转换为线偏振光的偏光片、用于引导第一光L1、第二光L2、第三光L3传输的光引导元件(例如反射片、柱透镜)等等。本申请中主要对与本申请相关的元件作介绍。其它元件不再赘述。另，本实施例的附图中所示元件结构的数量并不用于限定本申请，例如图2中所示每一衍射区21中驱动电极22的数量，或图3中所示输出通道31和输入通道32的数量等。上述元件的数量在不同实施例中皆可不同，附图仅作示例。
本实施例的波长选择开关100，每一输出通道31用于接收至少一束第三光L3的目标衍射级，对于每一输出通道31，通过设置其模场半径与其所接收的至少一束第三光L3的目标衍射级的束腰半径相等，可减小输出通道31的信号光的插入损耗；通过设置其模场半径与其所接收的第三光L3中除目标衍射级之外的其它衍射级中至少一衍射级的束腰半径不相等，或/和设置其模场半径与其它第三光L3中至少一束第三光L3的束腰半径不相等，可增加输出通道31的串扰光的插入损耗。通过减小输出通道31的信号光的插入损耗和增加输出通道31的串扰光的插入损耗，可提升波长选择开关100的隔离度。
实施例二
请参阅图5，本实施例的波长选择开关，与实施例一中波长选择开关100的区别主要在于：调节第三光L3的束腰半径的方式不同。本实施例中，通过调节各个透镜40的曲率半径来调节第三光L3的束腰半径的方式，取代实施例一中通过调节驱动电极22上驱动电压来调 节第三光L3的束腰半径的方式。光衍射模块20对第二光L2的作用可等效于一透镜，因此在前述实施例一中，调节各个驱动电极22上的驱动电压，也可视作等效于调节一透镜的曲率半径。
透镜40的曲率半径不同时，可使得透镜40所聚焦的第三光L3的束腰半径不同。本实施例中，通过设置每一透镜40的曲率半径，使得每一透镜40所引导的第三光的目标衍射级的束腰半径于对应的输出通道31的模场半径相等。并且，通过设置至少一透镜40的曲率半径不同于其它透镜40的曲率半径，使得该至少一个透镜40所引导的第三光L3的目标衍射级的束腰半径不同于其它第三光L3的束腰半径，也即使得其它第三光L3的束腰半径不同于该至少一个透镜40所对应的输出通道31的模场半径。上述可实现该至少一个透镜40所引导的第三光L3与对应的输出通道31模场匹配，且实现其它第三光L3与该对应的输出通道31模场失配，因此可实现减少信号光的插入损耗且增大串扰光的插入损耗，提升隔离度。
于本实施例的一变更实施例中，多个透镜40的曲率半径互不相等，使得各个透镜40所聚焦的第三光L3的束腰半径各不相等，从而每一输出通道31的模场半径不同于任意一种串扰光的束腰半径，可进一步增大每种串扰光的插入损耗，从而有利于进一步提升隔离度。
本实施例的波长选择开关，可实现如实施例一中波长选择开关100的所有有益效果。在此基础上，本实施例还提供了通过调节多个透镜40的曲率半径取代调节多个驱动电极22上的驱动电压的技术方案。
于本申请的一变更实施例中，可在调节各个透镜40的曲率半径的基础上，同时配合调节施加至各个驱动电极22上的驱动电压，实现对每一输出通道31的信号光的束腰半径和串扰光的束腰半径的调节(也即实现对每一第三光L3的束腰半径的调节)，使得信号光与输出通道31模场匹配，且使得串扰光与输出通道31模场失配，从该两个方面提升隔离度。
于本申请的另一变更实施例中，在利用模场匹配、模场失配的原理提升隔离度的基础上，还利用相干相消原理和径向失配原理以进一步提升波长选择开关的隔离度。
如前述的，本实施例中，每一输出通道31用于接收一束或多束第三光L3的+1衍射级，通过调节各个驱动电极22上的驱动电压，可调节第三光L3的其它衍射级的相位，使得每一第三光L3中除+1衍射级之外的其它衍射级至少部分相互抵消，减少第三光L3中除了+1衍射级之外的衍射级耦合至输出通道31的量。也即，通过相干相消的方式减少了串扰光，增大了串扰光的插入损耗，有利于提升隔离度。而对于径向失配，可通过增大各个输出通道31之间的间距实现。
因此，上述的另一变更实施例，在实现如前述的有益效果的基础上，还有利于进一步提升波长选择开关的隔离度。
实施例三
本实施例的波长选择开关，与实施例一中波长选择开关的区别主要在于，输出通道31和输入通道32的排列方式不同。
请参阅图6，本实施例中，光传输模块30包括多个输出通道31和一输入通道32。
实施例一中，输入通道32和多个输出通道31平行排列且输入通道位于多个输出通道31的同一侧。也即，实施例一中，光传输模块30包括多个平行排列的光传输通道，其中最左侧或最右侧的一光传输通道作为光输入通道32。
而本实施例中，输入通道32和多个输出通道31平行排列，多个输出通道31分别位于输入通道32的两侧。也即，以图6的方位为基准，本实施例中，部分输出通道31位于输入通 道32的左侧，另一部分输出通道31位于输入通道32的右侧。且本实施例中，位于输入通道32左侧和右侧的输出通道31的数量相等。于本实施例的一变更实施例中，位于输入通道32左侧和右侧的输出通道31的数量可不同。
本实施例的波长选择开关可实现实施例中波长选择开关100的所有有益效果，因此本实施例中波长选择开关的隔离度得到有效提升。在波长选择开关的隔离度提升的基础上，各个输出通道31之间的串扰被减小，可设置本实施例中波长选择开关实现“双边衍射”。也即使得本实施例中，多个输出通道31分别位于输入通道32的两侧，第三光L3从输入通道32两侧的输出通道31输出，且本实施例中，目标衍射级包括两个衍射级：+1衍射级和-1衍射级，+1衍射级和-1衍射级分别从于输入通道32左右两侧的输出通道31输出。
本实施例的波长选择开关通过采用上述的“双边衍射”，使得多个输出通道31和输入通道32之间的间距可有效缩小，从而有利于提升波长选择开关的集成度。
本实施例中，输入通道32和多个输出通道31的排列方式也可应用于实施例二中，也可实现相同的技术效果。
本技术领域的普通技术人员应当认识到，以上的实施方式仅是用来说明本发明，而并非用作为对本发明的限定，只要在本发明的实质精神范围之内，对以上实施例所作的适当改变和变化都落在本发明要求保护的范围之内。

Claims (13)

  1. 一种波长选择开关，其特征在于，包括：
    分光模块，用于接收第一光并对所述第一光进行分束，以输出多束第二光，所述多束第二光具有不同的波长；
    光衍射模块，位于所述多束第二光的光路上，用于接收并衍射所述多束第二光，以出射多束第三光，所述光衍射模块包括多个衍射区，所述多个衍射区与所述多束第二光一一对应，每一所述衍射区用于衍射所对应的一束第二光并出射一束所述第三光；以及
    光传输模块，位于所述多束第三光的光路上，所述光传输模块包括多个输出通道，每一所述输出通道用于接收至少一束第三光的目标衍射级并输出，每一所述输出通道的模场半径与所接收的所述至少一束第三光的目标衍射级的束腰半径相等；
    所述至少一束第三光的目标衍射级的束腰半径不同于所述至少一束第三光的其它衍射级中至少一个衍射级的束腰半径，或/和所述至少一束第三光的目标衍射级的束腰半径不同于其它第三光中至少一束第三光的束腰半径。
  2. 如权利要求1所述的波长选择开关，其特征在于，所述至少一束第三光的目标衍射级的束腰半径不同于所述至少一束第三光的其它衍射级中任意一个衍射级的束腰半径，或/和所述至少一束第三光的目标衍射级的束腰半径不同于其它第三光中任意一束第三光的束腰半径。
  3. 如权利要求1所述的波长选择开关，其特征在于，还包括位于所述光衍射模块和所述光传输模块之间的多个透镜，所述多个透镜与所述多个输出通道一一对应；
    每一所述透镜用于接收所述至少一束第三光的目标衍射级并聚焦至所对应的所述输出通道。
  4. 如权利要求3所述的波长选择开关，其特征在于，所述多个透镜的曲率半径相等。
  5. 如权利要求3所述的波长选择开关，其特征在于，至少一个透镜的曲率半径不同于其它透镜的曲率半径。
  6. 如权利要求5所述的波长选择开关，其特征在于，所述多个透镜的曲率半径互不相等。
  7. 如权利要求1-6任一项所述的波长选择开关，其特征在于，所述光衍射模块为硅基液晶，通过分别调节施加至所述多个衍射区的驱动电压，分别调节所述多束第三光的各个衍射级的束腰半径。
  8. 如权利要求1-7任一项所述的波长选择开关，其特征在于，所述目标衍射级包括一个衍射级。
  9. 如权利要求8所述的波长选择开关，其特征在于，所述目标衍射级为+1衍射级。
  10. 如权利要求1-7任一项所述的波长选择开关，其特征在于，所述目标衍射级包括两个衍射级。
  11. 如权利要求10所述的波长选择开关，其特征在于，所述目标衍射级包括+1衍射级和-1衍射级。
  12. 如权利要求1-11任一项所述的波长选择开关，其特征在于，所述光传输模块还包括一输入通道，所述输入通道用于接收所述第一光并传输所述第一光至所述分光模块。
  13. 如权利要求1-12任一项所述的波长选择开关，其特征在于，所述第一光中各个波长的光的束腰半径相等。
PCT/CN2022/102470 2021-07-02 2022-06-29 波长选择开关 WO2023274317A1 (zh)

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Citations (4)

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US20090220192A1 (en) * 2008-02-28 2009-09-03 Olympus Corporation Wavelength selective switch with reduced chromatic dispersion and polarization-dependent loss
CN103443700A (zh) * 2011-03-14 2013-12-11 剑桥企业有限公司 光束路由设备和方法
CN108293155A (zh) * 2015-09-23 2018-07-17 ROADMap系统有限公司 光切换系统
CN112987185A (zh) * 2021-03-03 2021-06-18 东南大学 一种工作区域复用型波长选择开关装置的控制方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090220192A1 (en) * 2008-02-28 2009-09-03 Olympus Corporation Wavelength selective switch with reduced chromatic dispersion and polarization-dependent loss
CN103443700A (zh) * 2011-03-14 2013-12-11 剑桥企业有限公司 光束路由设备和方法
CN108293155A (zh) * 2015-09-23 2018-07-17 ROADMap系统有限公司 光切换系统
CN112987185A (zh) * 2021-03-03 2021-06-18 东南大学 一种工作区域复用型波长选择开关装置的控制方法

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