WO2024011521A1 - Commutateur sélectif en longueur d'onde et procédé de modulation de faisceau lumineux - Google Patents

Commutateur sélectif en longueur d'onde et procédé de modulation de faisceau lumineux Download PDF

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Publication number
WO2024011521A1
WO2024011521A1 PCT/CN2022/105778 CN2022105778W WO2024011521A1 WO 2024011521 A1 WO2024011521 A1 WO 2024011521A1 CN 2022105778 W CN2022105778 W CN 2022105778W WO 2024011521 A1 WO2024011521 A1 WO 2024011521A1
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phase
diffraction order
distribution
light
output port
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PCT/CN2022/105778
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English (en)
Chinese (zh)
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闻远辉
卢特安
宗良佳
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华为技术有限公司
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Priority to PCT/CN2022/105778 priority Critical patent/WO2024011521A1/fr
Publication of WO2024011521A1 publication Critical patent/WO2024011521A1/fr

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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

Definitions

  • the present application relates to the field of optical communications, and in particular to a wavelength selective switch and a beam modulation method.
  • ROADM Reconfigurable Optical Add-Drop Multiplexer
  • WSS wavelength selective switch
  • SLM spatial light modulator
  • Embodiments of the present application provide a wavelength selective switch and a beam modulation method, which improves the isolation of the output port and reduces crosstalk at the output port.
  • WSS includes: port component, dispersion component, lens component, SLM and controller.
  • the port component includes input port and multiple output ports.
  • the dispersion component is used to decompose the combined beam from the input port into multiple sub-wavelength beams, and guide the multiple sub-wavelength beams to the lens assembly.
  • the lens assembly is used to direct multiple sub-wavelength beams to different areas of the SLM.
  • the controller is used to adjust the phase distribution corresponding to the pixels on the SLM.
  • SLM is used to separately modulate multiple sub-wavelength beams.
  • the sub-wavelength beam is modulated by SLM to form multiple diffraction order beams.
  • the light field distribution of the target diffraction order beam matches the light field mode supported by the output port.
  • the light field distribution of at least one diffraction order beam matches the light field distribution of the target diffraction order beam.
  • the light field distribution of the target diffraction order beam is different.
  • the lens assembly is also used to guide the modulated multiple sub-wavelength beams to the dispersion assembly.
  • the dispersion component is also used to combine the modulated multiple sub-wavelength beams and transmit them to multiple output ports.
  • the light field distribution of the light beam of the target diffraction order matches the light field mode supported by the output port, that is, the light beam of the target diffraction order can be efficiently coupled to the output port.
  • the light field distribution is different from the light field distribution of the target diffraction order beam, which will cause the light spot to be dispersed to varying degrees, making it difficult to couple into the output port, thereby improving the isolation of the output port. degree, reducing crosstalk at the output port.
  • the light field distribution includes the intensity distribution of the light field and/or the phase distribution of the light field.
  • the different light field distribution of the light beam may be caused by at least one of the following factors.
  • the beam types can be different.
  • the size of the beams may be different.
  • the relative positions of the light beam and the output port may be different.
  • a variety of factors affecting light field distribution are provided, which expands the application scenarios of this solution.
  • matching the light field distribution of the light beam of the target diffraction order with the light field mode supported by the output port can be manifested in that the coupling efficiency of the light beam of the target diffraction order coupled into the output port is greater than or equal to the threshold value. Based on this, the coupling efficiency of light beams of other crosstalk diffraction orders coupled into the output port is less than the threshold, which improves the isolation of the output port and reduces crosstalk at the output port.
  • the beam of the target diffraction order is a Gaussian beam
  • the beam of the target diffraction order has the same beam waist size as the Gaussian mode supported by the output port
  • the beam waist is located at the output port.
  • the beam of at least one diffraction order is a non-Gaussian beam, or the beam of at least one diffraction order has a different beam waist size from the Gaussian mode supported by the output port, or the beam waist of at least one diffraction order deviates from the output port. . Therefore, only the beam of the target diffraction order can be well coupled into the output port that supports Gaussian mode. Beams of other diffraction orders are difficult to couple into the output port, which improves the isolation of the output port and reduces crosstalk at the output port.
  • the controller specifically adjusts the phase distribution corresponding to the pixels on the SLM based on the beam deflection phase, disturbance phase and compensation phase.
  • the beam deflection phase acts on the deflection direction adjustment of each sub-wavelength beam
  • the disturbance phase acts on the phase modulation corresponding to each diffraction order
  • the compensation phase is used to compensate for the disturbance phase.
  • the perturbation phase and the compensation phase corresponding to the target diffraction order cancel each other, and the perturbation phase and the compensation phase corresponding to at least one diffraction order cannot cancel each other.
  • the beam deflection phase it can be regarded that only the beam deflection phase plays a role.
  • the light field distribution of the beams of other diffraction orders is different from the light field distribution of the beam of the target diffraction order.
  • the perturbation phase and the compensation phase are introduced based on the traditional beam deflection phase.
  • the disturbance phase and the compensation phase can be completely offset to maintain the original ideal spot shape, match the light field mode supported by the output port, and can be efficiently coupled to the output port.
  • the light spot will be dispersed to varying degrees, which is different from the light field distribution of the target diffraction order, making it difficult to couple into the output port, thereby improving the output.
  • the port isolation reduces crosstalk at the output port.
  • the controller can dynamically adjust the distribution characteristics of the disturbance phase and the compensation phase according to actual needs to control the light field distribution form of the crosstalk light, so that it can be suitable for different application scenarios and has higher flexibility.
  • this solution is implemented through special encoding by SLM on a conventional equal-focal optical system. It does not require a specific optical path design or the introduction of additional hardware, so it is easier to implement and lower cost.
  • the beam deflection phase has a functional relationship with the perturbation phase or the compensation phase.
  • This embodiment provides a specific implementation method for adjusting the phase distribution corresponding to pixels on the SLM, which enhances the practicality of this solution.
  • the disturbance phase and the compensation phase satisfy the quadratic phase distribution, which enhances the realizability of this solution.
  • this implementation method is suitable for scenarios where all output ports have crosstalk. It is necessary to make the disturbance phase and compensation phase corresponding to each diffraction order except the target diffraction order have different degrees of mismatch, so as to have different degrees of mismatch with the target diffraction order.
  • the different light field distribution makes it difficult for light of all diffraction orders except the target diffraction order to be coupled to the output port.
  • the perturbation phase and the compensation phase satisfy the binary grating phase distribution, which enhances the scalability of this solution.
  • this implementation is suitable for scenarios where some output ports have crosstalk. It can be adjusted in a targeted manner so that the disturbance phase and the compensation phase corresponding to some specified diffraction orders in addition to the target diffraction order have different degrees of mismatch, thereby having the following advantages: The light field distribution is different from the target diffraction order, and the light achieving this part of the specified diffraction order is difficult to couple to the output port.
  • the beam deflection phase is a phase grating with periodic distribution to facilitate beam deflection.
  • embodiments of the present application provide a beam modulation method.
  • the method includes the following steps. First, adjust the phase distribution corresponding to the pixels on the spatial light modulator SLM. Furthermore, the input multiple sub-wavelength beams are modulated respectively by SLM. The sub-wavelength beams are modulated by SLM to form beams of multiple diffraction orders.
  • the light field distribution of the target diffraction order beam is consistent with the light field supported by the output port. Mode matching, the light field distribution of the beam of at least one diffraction order is different from the light field distribution of the beam of the target diffraction order.
  • the light field distribution includes the intensity distribution of the light field and/or the phase distribution of the light field.
  • the different light field distribution of the light beam may be caused by at least one of the following factors.
  • the beam types can be different.
  • the size of the beams may be different.
  • the relative positions of the light beam and the output port may be different.
  • a variety of factors affecting light field distribution are provided, which expands the application scenarios of this solution.
  • matching the light field distribution of the light beam of the target diffraction order with the light field mode supported by the output port can be manifested in that the coupling efficiency of the light beam of the target diffraction order coupled into the output port is greater than or equal to the threshold value. Based on this, the coupling efficiency of light beams of other crosstalk diffraction orders coupled into the output port is less than the threshold, which improves the isolation of the output port and reduces crosstalk at the output port.
  • the beam of the target diffraction order is a Gaussian beam
  • the beam of the target diffraction order has the same beam waist size as the Gaussian mode supported by the output port
  • the beam waist is located at the output port.
  • the beam of at least one diffraction order is a non-Gaussian beam, or the beam of at least one diffraction order has a different beam waist size from the Gaussian mode supported by the output port, or the beam waist of at least one diffraction order deviates from the output port. . Therefore, only the beam of the target diffraction order can be well coupled into the output port that supports Gaussian mode. Beams of other diffraction orders are difficult to couple into the output port, which improves the isolation of the output port and reduces crosstalk at the output port.
  • adjusting the phase distribution corresponding to the pixels on the spatial light modulator SLM includes: adjusting the phase distribution corresponding to the pixels on the SLM according to the beam deflection phase, the disturbance phase and the compensation phase.
  • the beam deflection phase acts on the deflection direction adjustment of each sub-wavelength beam
  • the disturbance phase acts on the phase modulation corresponding to each diffraction order
  • the compensation phase is used to compensate for the disturbance phase.
  • the perturbation phase and the compensation phase corresponding to the target diffraction order cancel each other, and the perturbation phase and the compensation phase corresponding to at least one diffraction order cannot cancel each other.
  • the beam deflection phase has a functional relationship with the perturbation phase or the compensation phase.
  • the disturbance phase and the compensation phase satisfy a quadratic phase distribution.
  • the perturbation phase and the compensation phase satisfy a binary grating phase distribution.
  • the beam deflection phase is a phase grating with periodic distribution.
  • the disturbance phase and the compensation phase are introduced on the basis of the traditional beam deflection phase.
  • the disturbance phase and the compensation phase can be completely offset to maintain the original ideal spot shape, match the light field mode supported by the output port, and can be efficiently coupled to the output port.
  • the light spot will be dispersed to varying degrees, which is different from the light field distribution of the target diffraction order, making it difficult to couple into the output port, thereby improving the output.
  • the port isolation reduces crosstalk at the output port.
  • the controller can dynamically adjust the distribution characteristics of the disturbance phase and the compensation phase according to actual needs to control the light field distribution form of the crosstalk light, so that it can be suitable for different application scenarios and has higher flexibility.
  • this solution is implemented through special encoding by SLM on a conventional equal-focal optical system. It does not require a specific optical path design or the introduction of additional hardware, so it is easier to implement and lower cost.
  • FIG. 1 is a schematic structural diagram of WSS in an embodiment of the present application.
  • FIG. 2 is several schematic diagrams of light field distribution of light beams in embodiments of the present application.
  • Figure 3 is a schematic diagram of the transmission of sub-beams of different diffraction orders in the embodiment of the present application.
  • Figure 4 is a first morphological difference diagram between a special encoded grating and a traditional encoded grating in the embodiment of the present application;
  • Figure 5 is a first schematic diagram of the diffraction light field distribution in the embodiment of the present application.
  • Figure 6 is a second morphological difference diagram between a special encoded grating and a traditional encoded grating in the embodiment of the present application;
  • Figure 7 is a second schematic diagram of the diffraction light field distribution in the embodiment of the present application.
  • Figure 8 is a schematic flow chart of the first beam modulation method provided by the embodiment of the present application.
  • FIG. 9 is a schematic flowchart of the second beam modulation method provided by an embodiment of the present application.
  • Embodiments of the present application provide a wavelength selective switch and a beam modulation method.
  • the light field distribution of the beam of the target diffraction order matches the light field mode supported by the output port, that is, the beam of the target diffraction order can be efficiently coupled to the output port.
  • the light field distribution is different from the light field distribution of the target diffraction order beam, which will cause the light spot to be dispersed to varying degrees, making it difficult to couple into the output port, thereby improving the isolation of the output port. degree, reducing crosstalk at the output port.
  • the beam modulation method provided in the embodiment of this application is beam modulation realized by a spatial light modulator (Spatial Light Modulator, SLM).
  • SLM is a type of optical device that modulates the light field wavefront.
  • the spatial light modulator based on Liquid Crystal on Silicon (LCOS) technology has flexible light field control, repeatable erasing and high resolution.
  • LCOS Liquid Crystal on Silicon
  • this beam modulation method is mainly used in scenarios involving beam deflection, such as wavelength selective switch (WSS), radar scanning or space optical communication.
  • WSS wavelength selective switch
  • the following takes the application scenario of WSS as an example to introduce in detail.
  • FIG. 1 is a schematic structural diagram of a WSS in an embodiment of the present application.
  • the WSS includes a port component 10 , a dispersion component 20 , a lens component 30 , a spatial light modulator 40 and a controller 50 .
  • the port component 10 includes an input port 101 and a plurality of output ports 102 .
  • the input port 101 inputs a combined light beam including multiple wavelengths.
  • the combined light beam includes a total of n wavelengths ⁇ 1, ⁇ 2... ⁇ n.
  • the dispersion component 20 can decompose the multiplexed beam from the input port 101 into multiple sub-wavelength beams along the dispersion direction as shown in FIG.
  • the lens assembly 30 is used to guide the plurality of sub-wavelength beams to different areas of the spatial light modulator 40 respectively.
  • the spatial light modulator 40 modulates the input multiple sub-wavelength beams respectively according to the phase distribution loaded by the controller 50, so that the deflection direction of each sub-wavelength beam can be changed.
  • the modulated plurality of sub-wavelength light beams are sequentially transmitted to the plurality of output ports 102 through the lens assembly 30 and the dispersion assembly 20 .
  • the port assembly 10, the lens assembly 30 and the spatial light modulator 40 constitute an isofocal optical system.
  • the deflection direction of the light beam is also the port direction, so that the deflection direction of each sub-wavelength light beam can be adjusted to transmit it to the corresponding output port.
  • the dispersion direction is usually perpendicular to the port direction. Multiple modulation areas can be divided along the dispersion direction on the SLM to separately modulate the incident multiple sub-wavelength beams. After the modulated sub-wavelength light beam is incident on the dispersion component 20, the dispersion component 20 is also used to combine the incident sub-wavelength light beam along the dispersion direction and then output it.
  • the implementation form of the port component 10 includes but is not limited to an optical fiber array, a waveguide array, etc., and may be a one-dimensional array or a two-dimensional array.
  • the implementation forms of the dispersion component 20 include but are not limited to gratings, prisms, etc.
  • the implementation forms of the lens assembly 30 include but are not limited to ball lenses, cylindrical lenses, curved mirrors, etc.
  • the spatial light modulator 40 may specifically use an LCOS array.
  • the LCOS array has a pixelated modulation area, and the deflection direction of each sub-wavelength light beam can be changed by modulating the pixels in the corresponding wavelength area.
  • the spatial light modulator 40 can transmit the entire sub-wavelength beam to the output port 102 without loss by changing the deflection direction of the sub-wavelength beam, or make the sub-wavelength beam transmit to the output port 102 without loss.
  • the wavelength beam cannot be transmitted to the output port 102 , or part of the sub-wavelength beam can be transmitted to the output port 102 .
  • the port assembly 10 and the spatial light modulator 40 are located at the front focal plane and the rear focal plane of the lens assembly 30, respectively.
  • the optical path design in the WSS shown in Figure 1 is just an example, and other optical path designs can also be used in practical applications, so that various commonly used optical path designs in WSS can be adapted.
  • the WSS may also use a transmissive dispersion component 20 .
  • the port assembly 10 and the spatial light modulator 40 are respectively located on the front focal plane and the rear focal plane of the lens assembly 30 to form an equifocal optical system.
  • the spatial light modulator specifically adjusts the phase distribution corresponding to each pixel point according to the beam deflection phase loaded by the controller 50 to adjust the deflection direction of each sub-wavelength beam.
  • the beam deflection phase may be a phase grating with periodic distribution, such as a zigzag distributed blazed grating, a rectangular distributed binary grating, etc.
  • After the sub-wavelength beam irradiates the phase grating, it will be diffracted and propagate in various directions. The propagation direction follows the following grating equation: p(sin ⁇ +sin ⁇ ) n ⁇ .
  • n is any integer. Different n corresponds to different diffraction orders. Generally, +1 order diffraction light is commonly used. That is to say, each sub-wavelength beam has multiple diffraction orders, and light of different diffraction orders propagates in different directions. For example, part of the sub-wavelength beam with wavelength ⁇ 1 is transmitted toward the specified target output port, while the other part of the light is diffracted in other directions, causing crosstalk at non-target output ports.
  • the phase modulation encoding method of the spatial light modulator 40 can be adjusted through the controller 50, and the disturbance phase and the compensation phase can be further introduced on the basis of the beam deflection phase, so that the light of the target diffraction order can be maintained
  • the original ideal light spot shape can be efficiently coupled to the target output port, while the beams of other diffraction orders will be dispersed to varying degrees and have different light field distributions from the target diffraction order, making it difficult to couple into the output port to avoid affecting other beams. Crosstalk on non-intended output ports.
  • the sub-wavelength beam is modulated by the spatial light modulator 40 to form a beam of multiple diffraction orders, wherein the light field distribution of the target diffraction order beam matches the light field mode supported by the output port.
  • the light field distribution of at least one other diffraction order beam is different from the light field distribution of the target diffraction order beam. That is to say, the light field distribution of at least one other diffraction order beam is different from the light field mode supported by the output port. match. Therefore, the beam of the target diffraction order can be efficiently coupled to the output port, while the beam of at least one other diffraction order is difficult to couple into the output port.
  • whether the light field distribution of the light beam matches the light field mode supported by the output port can be judged by the coupling efficiency of the light beam coupled into the output port.
  • the coupling efficiency of the target diffraction order beam coupled into the output port is greater than or equal to the threshold, which matches the light field mode supported by the output port.
  • the coupling efficiency of light beams of other diffraction orders coupled into the output port is less than the threshold and does not match the light field mode supported by the output port.
  • the threshold can be flexibly set according to the actual application scenario, for example, it can be 60%, and there is no specific limit here.
  • the light field distribution of the light beam includes the intensity distribution of the light field and/or the phase distribution of the light field.
  • the different light field distribution of the light beam may be caused by at least one of the following factors.
  • the beam types can be different.
  • the size of the beams may be different.
  • the relative position of the light beam and the output port may be different, which is represented by whether the light beam is aligned with the output port.
  • FIG. 2 is several schematic diagrams of light field distribution of light beams in embodiments of the present application.
  • the beam of the target diffraction order is a Gaussian beam
  • the Gaussian beam has the same beam waist size as the Gaussian mode supported by the output port, and the beam waist of the Gaussian beam is located at the output port, which can be coupled efficiently. input and output ports.
  • the above-mentioned "same girdle size" does not necessarily mean exactly the same, but may also refer to similar girdle sizes.
  • beams of other diffraction orders may be non-Gaussian beams.
  • Example A Compared with Example A, their light field distribution is different from that of Example A due to different beam types.
  • the beams of other diffraction orders can be Gaussian beams, but the Gaussian beam has a different beam waist size from the Gaussian mode supported by the output port.
  • the beams of other diffraction orders can be Gaussian beams, but the beam waist of the Gaussian beam deviates from the output port.
  • the light field distribution is different due to the relative position of the beam and the output port. Light field distribution different from example A.
  • the light field distribution of the target diffraction order beam in example A matches the light field mode supported by the output port and can be efficiently coupled into the output port.
  • the light field distribution of the beams of other diffraction orders in examples B, C, or D does not match the light field mode supported by the output port, and it is difficult to couple into the output port.
  • Figure 3 is a schematic diagram of the transmission of different diffraction order beams in the embodiment of the present application.
  • the method provided by this application is not used to adjust the phase modulation encoding method of the spatial light modulator 40 , light of all diffraction orders can be well coupled into the output port, thereby causing crosstalk.
  • the beam of the target diffraction order and the beam of the partial crosstalk diffraction order have different beam types.
  • the beam of the target diffraction order and the beam of the partial crosstalk diffraction order have different beam sizes.
  • the beam of the target diffraction order can be aligned with the output port, but the beam of some crosstalk diffraction orders cannot be aligned with the output port.
  • the light field distribution of the beam of the target diffraction order matches the light field mode supported by the output port, and can be efficiently coupled into the output port.
  • the beams of some crosstalk diffraction orders do not match the light field modes supported by the output port, and are difficult to couple into the output port.
  • controller 50 adjusts the phase distribution corresponding to the pixels on the spatial light modulator 40 .
  • the controller 50 adjusts the phase distribution corresponding to the pixels on the spatial light modulator 40 according to the beam deflection phase, disturbance phase and compensation phase.
  • the beam deflection phase acts on the deflection direction adjustment of each sub-wavelength beam
  • the disturbance phase acts on the phase modulation corresponding to each diffraction order
  • the compensation phase is used to compensate for the disturbance phase.
  • the perturbation phase and the compensation phase By designing the distribution of the perturbation phase and the compensation phase, the perturbation phase and the compensation phase corresponding to the target diffraction order in multiple diffraction orders can be canceled out.
  • the perturbation phase is represented by D(x)
  • the compensation phase is represented by C. (x)
  • D(x) -C(x).
  • the disturbance phase and compensation phase corresponding to at least one diffraction order except the target diffraction order cannot cancel each other, that is, D(x) ⁇ -C(x).
  • different perturbation phases will be introduced for different diffraction orders, and the introduction of perturbation phases will cause the original ideal form of light spot to be dispersed to varying degrees.
  • a compensation phase will be introduced to compensate for the disturbance phase.
  • the disturbance phase and compensation phase corresponding to the target diffraction order cancel each other out.
  • the spot of the target diffraction order will still maintain its original ideal shape and can be coupled to the target output. port.
  • the disturbance phase and compensation phase corresponding to at least one other diffraction order cannot cancel each other.
  • the light spot of this part of the diffraction order will be dispersed and have a different light field distribution from the target diffraction order, making it difficult to couple to the output port.
  • the beam deflection phase has a functional relationship with the disturbance phase or the compensation phase.
  • phase distribution corresponding to the pixels on the spatial light modulator is expressed as ⁇ (x).
  • ⁇ (x) f[G(x)-D(x)]+C(x)
  • ⁇ (x) f[G(x)-C(x)]+D(x).
  • G(x) represents the beam deflection phase
  • D(x) represents the disturbance phase
  • C(x) represents the compensation phase
  • f[G(x)-D(x)] represents the relationship between G(x)-D(x)
  • the associated function f[G(x)-C(x)] represents the function associated with G(x)-C(x).
  • the above functional relationship may use a remainder function.
  • ⁇ (x) mod[G(x)-D(x),2 ⁇ ]+C(x).
  • disturbance phase and compensation phase can adopt a variety of distribution forms. Two specific phase distribution forms are provided below.
  • Phase distribution form 1 The disturbance phase and the compensation phase satisfy the quadratic phase distribution.
  • the disturbance phase and the compensation phase may be secondary phase distributions with a lens function.
  • Figure 4 is a first morphological difference diagram between a special encoding grating and a traditional encoding grating in the embodiment of the present application.
  • the grating formed by introducing the disturbance phase and the compensation phase for encoding based on the traditional periodic grating can be called a special encoding grating.
  • this special encoded grating has similar period hopping characteristics to traditional periodic gratings, so that beam deflection can be achieved.
  • this special encoded grating has an overall envelope of the secondary phase.
  • Figure 5 is a first schematic diagram of the diffraction light field distribution in the embodiment of the present application.
  • the traditional periodic grating actually generates There is a certain deviation between the phase grating morphology and the ideal blazed grating that achieves beam deflection. Therefore, in addition to the +1 order diffraction order, other grating diffraction orders that are the same as the +1 order diffraction light field distribution will be produced.
  • the special encoded grating introduces the perturbation phase and the compensation phase with a quadratic phase distribution, and for the +1st diffraction order, the perturbation phase and the compensation phase can cancel each other and retain the original light field distribution, while other crosstalk diffraction Due to the different degrees of mismatch between the disturbance phase and the compensation phase, the orders retain the role of the secondary phase. Therefore, these crosstalk diffraction orders have different degrees of light field dispersion and have different light field distributions from the target diffraction orders. .
  • a crosstalk light dispersion effect similar to that of non-equifocal optical design can be achieved.
  • this solution can dynamically select different defocuss through coding to achieve different degrees.
  • the crosstalk light is dispersed, and there is no need to change the existing WSS optical design and assembly, which has more advantages in terms of function and implementation.
  • Phase distribution form 2 The disturbance phase and the compensation phase satisfy the binary grating phase distribution.
  • the disturbance phase and the compensation phase may be binary grating phase distributions.
  • the disturbance phase and the compensation phase may be binary grating phase distributions.
  • FIG. 6 is a second morphological difference diagram between a special encoding grating and a traditional encoding grating in the embodiment of the present application.
  • the grating formed by introducing the disturbance phase and the compensation phase for encoding based on the traditional periodic grating can be called a special encoding grating.
  • this special encoded grating has similar period hopping characteristics to traditional periodic gratings, so that beam deflection can be achieved.
  • this special encoded grating has an overall envelope of binary grating phases.
  • Figure 7 is a second schematic diagram of the diffraction light field distribution in the embodiment of the present application.
  • the traditional periodic grating actually produces due to the control pixel discretization of the LCOS device, the fringe field effect between pixels and the elastic interaction between liquid crystal molecules.
  • the special encoded grating introduces the perturbation phase and the compensation phase with a quadratic phase distribution, and for the +1st diffraction order, the perturbation phase and the compensation phase can cancel each other and retain the original light field distribution, while other crosstalk diffraction
  • the stages have varying degrees of mismatch due to both the disturbance phase and the compensation phase. Among them, for odd diffraction orders, since there are 0 and The binary grating is therefore unaffected. For even diffraction orders, since there are 0 and The binary grating is thus split into two halves and moved to different positions as the period of the binary grating changes.
  • phase distribution form 1 By comparing the two phase distribution forms introduced above, it can be seen that using the above-mentioned phase distribution form 1 can achieve different degrees of light field dispersion in all diffraction orders except the target diffraction order (+1 diffraction order), as shown in the figure 5 shown. Therefore, the above phase distribution form 1 is suitable for scenarios where all output ports have crosstalk. It is necessary to make the disturbance phase and compensation phase corresponding to each diffraction order except the target diffraction order have different degrees of mismatch, so as to achieve the goal of eliminating the target. Light of all diffraction orders except the diffraction order is difficult to couple to the output port.
  • phase distribution form 2 can achieve different degrees of light field dispersion in other diffraction orders except the target diffraction order (+1 diffraction order), as shown in Figure 7. Therefore, the above phase distribution form 2 is suitable for scenarios where some output ports have crosstalk. It can be adjusted in a targeted manner so that the disturbance phase and compensation phase corresponding to some specified diffraction orders except the target diffraction order have different degrees of mismatch. As a result, the light of this part of the specified diffraction order is difficult to couple to the output port.
  • the above two phase distribution forms can be flexibly selected according to different needs in practical applications.
  • the disturbance phase and the compensation phase can also adopt other distribution forms besides the two distribution forms introduced above, as long as the optical power distribution and peak intensity position of the crosstalk diffraction order can be adjusted to make it difficult to couple It can be connected to the output port, and there is no specific limit here.
  • the WSS provided by the embodiment of the present application is introduced above, and the beam modulation method provided by the embodiment of the present application is introduced below.
  • FIG. 8 is a schematic flowchart of the first beam modulation method provided by the embodiment of the present application. It should be noted that this beam modulation method can be applied in scenarios involving beam deflection including WSS.
  • the beam modulation method includes the following steps.
  • the disturbance phase and the compensation phase are further introduced on the basis of the beam deflection phase.
  • the beam deflection phase acts on the deflection direction adjustment of each sub-wavelength beam
  • the disturbance phase acts on the phase modulation corresponding to each diffraction order
  • the compensation phase is used to compensate for the disturbance phase.
  • the disturbance phase and the compensation phase corresponding to at least one diffraction order other than the target diffraction order cannot cancel each other, and the light field distribution at the output port plane is different from the light field distribution of the target diffraction order. Then, the light spot of the target diffraction order will still maintain its original ideal shape, so that it can be coupled to the target output port.
  • the disturbance phase and compensation phase corresponding to at least one other diffraction order cannot cancel each other, and the light spots of this part of the diffraction order will be dispersed, making it difficult to couple to the output port.
  • the spatial light modulator Based on the phase distribution corresponding to each pixel point on the spatial light modulator, the spatial light modulator will separately modulate the incident multiple sub-wavelength beams. While adjusting the deflection direction of the sub-wavelength beam, it will also change each diffraction order of the sub-wavelength beam. corresponding light field distribution. Taking one of the sub-wavelength beams that can cause crosstalk as an example, the spatial light modulator modulates the sub-wavelength beam so that the light of the target diffraction order maintains the original ideal spot shape and can be coupled to the target output port. The light field distribution of at least one other diffraction order is different from the light field distribution of the target diffraction order, making it difficult to couple to the output port.
  • the beam modulation method provided by the embodiment of the present application will be further introduced below in conjunction with the application scenario of WSS.
  • FIG. 9 is a schematic flowchart of the second beam modulation method provided by an embodiment of the present application. It should be noted that the structure of WSS and the functions of each module can be referred to the introduction of the embodiment shown in Figure 1 above, and details will not be described again here.
  • the beam modulation method includes the following steps.
  • an optical power detector can be used to measure the optical power of each output port in the WSS.
  • the output port that needs to suppress crosstalk can be determined based on the optical power of each output port. For example, an output port whose output optical power is greater than a preset optical power threshold can be identified as an output port that needs to suppress crosstalk.
  • the disturbance phase and the compensation phase can adopt various distribution forms. Therefore, the phase distribution form of the disturbance phase and the compensation phase can be determined according to the diffraction order corresponding to the output port where crosstalk needs to be suppressed.
  • the perturbation phase and the compensation phase can be selected as quadratic phase distribution.
  • the disturbance phase and compensation phase can be selected as binary grating phase distribution.
  • the phase distribution form of the disturbance phase and the compensation phase is adjusted, thereby re-modulating the light beam incident on the spatial light modulator.
  • the relevant introduction of step 801 in the embodiment shown in FIG. 8 please refer to the relevant introduction of step 801 in the embodiment shown in FIG. 8 , and will not be described again here.
  • step 95. Determine whether the output port that needs to suppress crosstalk meets the standard. If yes, perform step 906. If not, perform step 903 and step 904.
  • the disturbance phase and the compensation phase are introduced on the basis of the traditional beam deflection phase.
  • the disturbance phase and the compensation phase can be completely offset to maintain the original ideal spot shape, match the light field mode supported by the output port, and can be efficiently coupled to the output port.
  • the light spot will be dispersed to varying degrees, which is different from the light field distribution of the target diffraction order, making it difficult to couple into the output port, thereby improving the output.
  • the port isolation reduces crosstalk at the output port.
  • the controller can dynamically adjust the distribution characteristics of the disturbance phase and the compensation phase according to actual needs to control the light field distribution form of the crosstalk light, so that it can be suitable for different application scenarios and has higher flexibility.
  • this solution is implemented through special encoding by SLM on a conventional equal-focal optical system. It does not require a specific optical path design or the introduction of additional hardware, so it is easier to implement and lower cost.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

L'invention concerne un WSS et un procédé de modulation de faisceau lumineux, qui améliorent l'isolation des ports de sortie (102), et réduisent la diaphonie des ports de sortie (102). Le WSS comprend : un module de port (10), un module de dispersion (20), un module de lentille (30), un SLM (40) et un dispositif de commande (50). Le module de port (10) comprend un port d'entrée (101) et une pluralité de ports de sortie (102). Le module de dispersion (20) est utilisé pour diviser en une pluralité de faisceaux lumineux de sous-longueur d'onde des faisceaux multiplexés en longueur d'onde provenant du port d'entrée (101). Le module de lentille (30) est utilisé pour guider respectivement la pluralité de faisceaux lumineux de sous-longueur d'onde vers différentes régions du SLM (40). Le SLM (40) est utilisé pour moduler séparément la pluralité de faisceaux lumineux de sous-longueur d'onde, et la pluralité de faisceaux lumineux de sous-longueur d'onde modulés sont transmis séquentiellement à la pluralité de ports de sortie (102) au moyen du module de lentille (30) et du module de dispersion (20). Le dispositif de commande (50) est utilisé pour ajuster une distribution de phase correspondant à des points de pixel sur le SLM (40). Après avoir été modulé par le SLM (40), les faisceaux lumineux de sous-longueur d'onde forment des faisceaux lumineux d'une pluralité d'ordres de diffraction ; la distribution de champ lumineux d'un faisceau lumineux d'un ordre de diffraction cible est mise en correspondance avec un mode de champ lumineux supporté par lesdits ports de sortie (102) ; et la distribution de champ lumineux d'un faisceau lumineux d'au moins un ordre de diffraction est différente de la distribution de champ lumineux du faisceau lumineux de l'ordre de diffraction cible.
PCT/CN2022/105778 2022-07-14 2022-07-14 Commutateur sélectif en longueur d'onde et procédé de modulation de faisceau lumineux WO2024011521A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203311035U (zh) * 2013-06-20 2013-11-27 中央民族大学 一种基于硅基液晶的m×n端口的可重构光分插复用器
JP2017191252A (ja) * 2016-04-14 2017-10-19 日本電信電話株式会社 光入出力装置
CN108293155A (zh) * 2015-09-23 2018-07-17 ROADMap系统有限公司 光切换系统
CN111221081A (zh) * 2018-11-26 2020-06-02 华为技术有限公司 一种基于LCoS的波长选择开关
CN112269226A (zh) * 2020-11-16 2021-01-26 上海交通大学 一种混合调制方法及系统
CN114545557A (zh) * 2020-11-26 2022-05-27 华为技术有限公司 一种光处理装置及光学系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203311035U (zh) * 2013-06-20 2013-11-27 中央民族大学 一种基于硅基液晶的m×n端口的可重构光分插复用器
CN108293155A (zh) * 2015-09-23 2018-07-17 ROADMap系统有限公司 光切换系统
JP2017191252A (ja) * 2016-04-14 2017-10-19 日本電信電話株式会社 光入出力装置
CN111221081A (zh) * 2018-11-26 2020-06-02 华为技术有限公司 一种基于LCoS的波长选择开关
CN112269226A (zh) * 2020-11-16 2021-01-26 上海交通大学 一种混合调制方法及系统
CN114545557A (zh) * 2020-11-26 2022-05-27 华为技术有限公司 一种光处理装置及光学系统

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