WO2021147586A1

WO2021147586A1 - Liquid crystal on silicon drive method and driver circuit

Info

Publication number: WO2021147586A1
Application number: PCT/CN2020/137825
Authority: WO
Inventors: 常泽山; 宗良佳; 毛磊
Original assignee: 华为技术有限公司
Priority date: 2020-01-22
Filing date: 2020-12-19
Publication date: 2021-07-29
Also published as: CN113156675B; CN113156675A

Abstract

A liquid crystal on silicon drive method, a phase adjustment apparatus (600), a liquid crystal on silicon drive device (700) and a chip (800), used for a wavelength selector switch (100) including a liquid crystal on silicon (1). The liquid crystal on silicon (1) having thereon at least one light spot formed by an incident light beam, at least one first region of the light spot being loaded with a first voltage causing a phase modulation depth of the first region to be a first modulation depth, at least one second region of the light spot being loaded with a second voltage causing a phase modulation depth of the second region to be a second modulation depth, the second modulation depth being greater than the first modulation depth, and the first modulation depth and the second modulation depth being used to perform phase modulation of light beams entering the liquid crystal on silicon (1).

Description

Driving method and driving circuit of liquid crystal on silicon

This application claims the priority of a Chinese patent application filed with the State Intellectual Property Office of China, the application number is 202010073129.0, and the invention title is "driving method and driving circuit for silicon-based liquid crystal" on January 22, 2020, the entire content of which is incorporated by reference In this application.

Technical field

This application relates to the field of optical communications, and in particular to a driving method and driving circuit for liquid crystal on silicon.

Background technique

With the rapid growth of network traffic and bandwidth, operators have more and more urgent requirements for the intelligent scheduling function of the underlying WDM network, which leads to ROADM (Reconfigurable Optical Add-Drop Multiplexer, reconfigurable optical add-drop multiplexer) It is gradually adopted by more and more high-end operators' networks. After ROADM is introduced into the network, operators can quickly provide wavelength-level services, which facilitates network planning, reduces operating costs, facilitates maintenance, and reduces maintenance costs.

A typical ROADM node of C (colorless, colorless) D (directionless) C (contentionless, non-blocking) is composed of line-side modules and client-side modules. Among them, the line-side modules are stacked and interconnected by multiple wavelength selective switch (Wavelength selective switch, WSS) modules.

Liquid Crystal on Silicon (LCOS) is the core device of the wavelength selective switch. As technology is released, the diffraction angle of LCOS to the incident beam is increased, and the existing LCOS driving method cannot meet the insertion loss index when the diffraction angle is increased. Or bring crosstalk.

Summary of the invention

In view of this, the embodiments of the present application provide a driving method, driving circuit, driving device, and chip for liquid crystal on silicon, which can effectively reduce the interference of crosstalk light caused by high-profile processing, and can also move the position of crosstalk light. Make the output port avoid the interference of crosstalk light.

In the first aspect, an embodiment of the present application discloses a method for driving a liquid crystal on silicon, which is applied to a wavelength selective switch including liquid crystal on silicon, on which an incident light beam enters and forms at least one light spot. Methods include:

A first voltage is applied to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and a second voltage is applied to at least one second area on the light spot to make the phase modulation of the second area The depth is a second modulation depth, the light spot includes the at least one first region and the at least one second region, the second modulation depth is greater than the first modulation depth, and the first modulation depth and the second modulation depth are used for Phase modulation of the incident beam.

In a possible design, there are one or more first regions between every two adjacent second regions.

In a possible design, the first voltage is applied between the first electrode and the second electrode corresponding to the at least one first area on the light spot so that the phase modulation depth of the first area is the The first modulation depth, there is a liquid crystal layer between the first electrode and the second electrode; the first electrode is loaded between the third electrode and the fourth electrode corresponding to the at least one second area on the light spot The two voltages make the phase modulation depth of the second region the second modulation depth, and a liquid crystal layer is located between the third electrode and the fourth electrode.

In a possible design, the above-mentioned first modulation depth is 2π, and the second modulation depth is 4π.

In the second aspect, the embodiments of the present application also disclose a driving circuit for liquid crystal on silicon. The driving circuit is applied to a wavelength selective switch containing liquid crystal on silicon. The driving circuit includes an electrode layer and an integrated circuit module. The driving circuit includes Electrode layer and integrated circuit module. The integrated circuit module is used to control the voltage loaded on the electrode layer, including:

The integrated circuit module is configured to control the application of a first voltage on the electrode layer corresponding to at least one first area on the light spot so that the phase modulation depth of the first area becomes the first modulation depth;

The integrated circuit module is also used to control the application of a second voltage on the electrode layer corresponding to the at least one second area on the light spot so that the phase modulation depth of the second area is the second modulation depth, and the light spot includes the at least one first modulation depth. Area and at least one second area, the second modulation depth is greater than the first modulation depth.

In the third aspect, the embodiment of the present application discloses a phase modulation device, which is applied to a wavelength selective switch. The phase modulation device includes a liquid crystal on silicon and a driving circuit. A light beam is incident on the liquid crystal on silicon to form at least one light spot. The characteristic is that

The driving circuit is used to apply a first voltage to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth;

The driving circuit is also used to apply a second voltage to at least one second area on the light spot to make the phase modulation depth of the second area a second modulation depth, and the light spot includes the at least one first area and the At least one second area, the second modulation depth is greater than the first modulation depth, and the first modulation depth and the second modulation depth are used for phase modulation of the light beam.

In a possible design, the driving circuit includes a first electrode and a second electrode, and a first voltage is applied between the corresponding first electrode and the second electrode on at least one of the first areas of the light spot to modulate the phase of the first area. The depth is the first modulation depth; a second voltage is applied between the corresponding first electrode and the second electrode on at least one second area of the light spot to make the phase modulation depth of the second area the second modulation depth, the first electrode and There is a liquid crystal layer between the second electrodes.

In a fourth aspect, an embodiment of the present application discloses a driving device for liquid crystal on silicon, which is applied to a wavelength selective switch including liquid crystal on silicon, on which an incident light beam enters and forms at least one light spot. The device includes: a communication interface and a processor coupled to the communication interface;

The processor is used for:

A first voltage is applied to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and a second voltage is applied to at least one second area on the light spot to make the The phase modulation depth of the second region is a second modulation depth, the light spot includes the at least one first region and the at least one second region, and the second modulation depth is greater than the first modulation depth.

In the fifth aspect, the embodiments of the present application disclose a chip, which is applied to a wavelength selective switch containing liquid crystal on silicon, and is applied to a wavelength selective switch containing liquid crystal on silicon, on which an incident light beam enters and At least one light spot is formed, characterized in that the chip includes a memory and a processor, the memory stores computer program instructions, and the processor is used for the computer program instructions to make the chip execute any one of the first aspect method.

In the sixth aspect, the embodiments of the present application disclose a computer program product. When the computer program product runs on a computer, the computer is caused to execute any one of the methods in the first aspect.

Description of the drawings

FIG. 1 is a schematic structural diagram of a wavelength selective switch 100 provided by this application;

FIG. 2 is a schematic structural diagram of a liquid crystal on silicon 1 provided by this application;

FIG. 3 is a flowchart of a method for driving a liquid crystal on silicon disclosed in an embodiment of the application;

4a is a schematic diagram of an arrangement of high-profile areas and low-profile areas disclosed in an embodiment of the application;

FIG. 4b is a schematic diagram of another arrangement of high-profile areas and low-profile areas disclosed in an embodiment of the application;

5 is a schematic diagram of a driving circuit for liquid crystal on silicon disclosed in an embodiment of the application;

6 is a schematic diagram of a phase modulation device for liquid crystal on silicon disclosed in an embodiment of the application;

FIG. 7 is a schematic diagram of a driving device for liquid crystal on silicon disclosed in an embodiment of the application;

FIG. 8 is a schematic diagram of a chip disclosed in an embodiment of the application.

Detailed ways

The embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

Please refer to FIG. 1. A wavelength selective switch (Wavelength selective switch, WSS) 100 shown in FIG. 1 is an application scenario of an embodiment of the application. The wavelength selective switch 100 can be applied to ROADM (Reconfigurable Optical Add-Drop Multiplexer). The wavelength selective switch 100 includes a liquid crystal on silicon 1, and the liquid crystal on silicon (Liquid Crystal on Silicon, LCOS) is used as an optical switching engine of the wavelength selective switch 100 to realize a phase modulation effect to control the incident on the liquid crystal on silicon. 1Diffraction and deflection direction of light beams in different areas.

The wavelength selective switch 100 also includes at least one input port 101 (for example, an input fiber), at least one output port group corresponding to the input port 101, a polarization conversion unit 103, and a wavelength division multiplexer (WDM) 104 (for example, Diffraction grating) and lens 105. Each of the above-mentioned output port groups includes at least two output ports 102 (for example, output optical fibers). As shown in Figure 1, the beam transmission path in the figure is a reversible path. The multi-wavelength signal forms an input beam through the aforementioned input port 101. The input beam is converted by the polarization conversion unit 103 into linearly polarized light corresponding to the working polarization state of the liquid crystal on silicon 1. The linearly polarized light is incident on the wavelength division multiplexer 104, and the wavelength division multiplexer 104 disperses the wavelengths at different angles, and then the dispersed beams are converted into parallel beams by the lens 105 to be incident on the silicon-based liquid crystal 1 different positions. The light beams of different wavelengths are focused on different areas of the silicon-based liquid crystal 1 and are diffracted and deflected. The diffracted light beams are restored to the original polarization state by the polarization conversion unit 103, and the light beams of different wavelengths are coupled to respective target output ports 102. Since light beams of different wavelengths are individually controlled by different regions on the liquid crystal on silicon 1 to control their respective diffraction and deflection directions, the liquid crystal on silicon 1 can switch any combination of wavelengths to any of the aforementioned output ports 102. Wherein, the above-mentioned wavelength selective switch 100 further includes a reflecting mirror 106 for reflecting light.

Please refer to FIG. 2 in combination. The liquid crystal on silicon 1 shown in FIG. 2 is a hardware system that may be applied in the embodiment of the application, and can be applied to the above-mentioned wavelength selective switch 100. The above-mentioned liquid crystal on silicon 1 is used to diffract an incident light beam in a linear polarization state to form a deflected light beam. The liquid crystal on silicon 1 is a polarization sensitive device that can only work in one polarization direction (ie, the working polarization direction). The polarization direction of the light beam incident on the liquid crystal on silicon 1 is the working polarization direction of the liquid crystal on silicon 1. The liquid crystal on silicon 1 includes a first panel 11, a second panel 12, a liquid crystal layer 13, a driving circuit 14 and two alignment films (Alignment Film) 15. The first panel 11 and the second panel 12 are arranged opposite to each other. The first panel 11 is parallel to the second panel 12. The first panel 11 may be a silicon backplane, and the second panel 12 may be a transparent glass substrate. The liquid crystal layer 13 is located between the first panel 11 and the second panel 12. The driving circuit 14 is used to generate an electric field to control the deflection of the liquid crystal in the liquid crystal layer 13. Two alignment films 15 are respectively located on opposite sides of the liquid crystal layer 13. That is, one of the above-mentioned alignment films 15 is located between the liquid crystal layer 13 and the first panel 11, and the other alignment film 15 is located between the liquid crystal layer 13 and the second panel 12. The above-mentioned alignment film 15 is used to make the liquid crystal in the liquid crystal layer 13 have an initial orientation.

The driving circuit 14 includes a first electrode 141 and a second electrode 142. The first electrode 141 is located between the liquid crystal layer 13 and the first panel 11. The second electrode 142 is located between the liquid crystal layer 13 and the second panel 12. When the first electrode 141 and the second electrode 142 are energized, the deflection of the liquid crystal in the liquid crystal layer 13 is controlled through a vertical alignment (Vertically-aligned, VA) driving method. When a voltage is applied to the first electrode 141 and the second electrode 142 and an electric field is formed between the first electrode 141 and the second electrode 142, the liquid crystal in the liquid crystal layer 13 will be deflected. The deflection angle of the liquid crystal molecules is related to the magnitude of the voltage applied to the first electrode 141 and the second electrode 142, so different voltages can be applied to achieve different phase modulation amounts.

Since the liquid crystal on silicon includes many pixels, each grating segment is composed of some pixels, and each pixel can be configured with its own phase, that is, each pixel can be configured with its own phase modulation amount. The pixel points are arranged in a form in which the phase modulation amount changes periodically, so that the liquid crystal on silicon 1 has the function of a blazed grating. Among them, among all the pixels included in a grating segment, the maximum value of the phase modulation amount is the phase modulation depth. For example, if the phase modulation amount in the grating segment changes from 0-2π, the phase modulation depth is 2π. The phase modulation depth can also be understood as the modulation depth of the liquid crystal on silicon when the incident light beam is perpendicularly incident on the liquid crystal on silicon, under the maximum voltage range applied to the silicon substrate, the phase difference when the light leaves the liquid crystal layer.

When the liquid crystal on silicon realizes the light path switching, each pixel is loaded with a different voltage, thereby generating a step-shaped phase and presenting a periodic change. When the light hits the surface of the silicon-based liquid crystal, the following relationship d*sinθ=λ is satisfied, where d is the number of pixels in a period multiplied by the pixel length, θ is the deflection angle, and λ is the wavelength. For the same diffraction angle, the more pixels in a period, the smaller the diffraction loss. For the same silicon-based chip, the larger the diffraction angle, the smaller the number of pixels, and the greater the diffraction loss.

At present, liquid crystal on silicon with a phase modulation depth of 2π is commonly used in the industry. With the development of technology in recent years that the LCOS diffraction angle has become larger, the number of pixels in a single period will decrease, and the diffraction loss will increase. In order to meet the diffraction loss index, the embodiment of the present application adopts a liquid crystal on silicon with an increased maximum phase modulation depth, for example, it may be a liquid crystal on silicon with a maximum phase modulation depth of 4π.

It is worth noting that the embodiment of the present application divides the phase modulation processing of the liquid crystal on silicon into low-key processing and high-key processing. Both low-key processing and high-key processing are relative terms. In this application, the low-key processing is defined as the phase modulation depth used by the liquid crystal on silicon as the first modulation depth, and the high-key processing is the phase modulation depth used by the liquid crystal on silicon as the second modulation depth. Wherein, the second modulation depth is greater than the first modulation depth. Preferably, the first modulation depth is 2π, and the second modulation depth is 4π.

When the high-profile processing of the liquid crystal on silicon can increase the diffraction angle, the number of pixels is far more than that of the low-profile processing, and the diffraction loss is also greatly reduced relative to the low-profile processing. However, in the high-profile processing process, strong crosstalk light interference will be brought. For liquid crystal on silicon with the same maximum phase modulation depth, such as 4π, 2π phase modulation depth treatment can be used in some areas, and 4π phase modulation depth treatment in another part of the area, that is, the phase modulation depth of liquid crystal on silicon can not exceed its maximum Any modulation depth in the phase modulation depth.

The terms "first", "second", etc. in this application are used to distinguish similar objects, and not necessarily used to describe a specific sequence or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that The described embodiments can be implemented in a sequence not described in this application.

FIG. 3 is a flowchart of a method for driving liquid crystal on silicon disclosed in an embodiment of the application. As shown in FIG. 3, the driving method of the liquid crystal on silicon can be used in a wavelength selective switch including liquid crystal on silicon on which an incident light beam enters and forms at least one light spot. The method includes:

S301. Perform low-key processing on at least one first area of the light spot, and perform high-key processing on at least one second area of the light spot.

Specifically, low-key processing is performed in the first area, that is, a first voltage is applied to the first area to make the phase modulation depth of the first area the first modulation depth. High-profile processing is performed in the second area, that is, a second voltage is applied to the second area to make the phase modulation depth of the second area the second modulation depth, and the light spot coverage area includes the at least one first area and the In the at least one second region, the second modulation depth is greater than the first modulation depth.

Preferably, the first modulation depth is 2π, the first region can also be generally referred to as a low-key region; the second modulation depth is 4π. , The second area can also be called a high profile area.

Optionally, there are one or more first regions between every two adjacent second regions. For example, as shown in Fig. 4a, there is one low-key area in every two high-key areas; as shown in Fig. 4b, there are two low-key areas in every two high-key areas. In practice, there may be other arrangements of high-profile areas and low-profile areas. It should be understood that other combinations of various possible high-profile areas and low-profile areas that can achieve the purpose of the invention based on this solution should fall within the scope of protection of this application. .

Specifically, the first voltage is applied between two electrodes corresponding to the at least one first area on the light spot so that the phase modulation depth of the first area becomes the first modulation depth, and the two electrodes There is a liquid crystal layer;

Applying the second voltage between the other two electrodes corresponding to the at least one second area on the light spot makes the phase modulation depth of the second area the second modulation depth, and there is Liquid crystal layer.

The method for driving the liquid crystal on silicon disclosed in the embodiments of the present application can effectively reduce the interference of crosstalk light caused by the high-profile processing through the mixed arrangement of the high-profile area and the low-profile area, and at the same time, it can also move the position of the crosstalk light so that the output port can be avoided. Crosstalk light interference.

FIG. 5 is a driving circuit 500 disclosed in an embodiment of the application, which is applied to a wavelength selective switch including liquid crystal on silicon. An incident light beam is incident on the liquid crystal on silicon to form at least one light spot. The driving circuit includes an electrode layer. 501 and integrated circuit module 502. The integrated circuit module 502 is used to control the voltage loaded on the electrode layer 501, and specifically includes:

The integrated circuit module 502 is configured to control the application of a first voltage on the electrode layer corresponding to at least one first region on the light spot so that the phase modulation depth of the first region becomes the first modulation depth;

The integrated circuit module 502 is further configured to control the application of a second voltage on the electrode layer corresponding to the at least one second area on the light spot so that the phase modulation depth of the second area is the second modulation depth, and the light spot includes the at least one first area. For one area and at least one second area, the second modulation depth is greater than the first modulation depth.

Optionally, there are one or more first regions between every two adjacent second regions.

Optionally, the electrode layer 501 includes a first electrode and a second electrode, and the first voltage or the second voltage is applied through the first electrode and the second electrode. For example, a first voltage is applied between the first electrode and the second electrode corresponding to the first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and the first electrode and the second electrode There is a liquid crystal layer in between.

6 is a phase modulation device 600 disclosed in an embodiment of the application, which is applied to a wavelength selective switch. The phase modulation device includes a liquid crystal on silicon 601 and a driving circuit 602. A light beam is incident on the liquid crystal on silicon and forms at least one light spot. ,

The driving circuit is used for applying a first voltage to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth;

The driving circuit is also used to apply a second voltage to at least one second area on the light spot to make the phase modulation depth of the second area a second modulation depth, the second modulation depth is greater than the first modulation depth, and the first modulation depth And the second modulation depth is used to phase modulate the light beam.

The liquid crystal on silicon 601 may be the liquid crystal on silicon 1 shown in FIG. 2, and the driving circuit 602 may be the driving circuit 500 shown in FIG. 5.

Optionally, the driving circuit 602 includes a first electrode and a second electrode, and a first voltage is applied between the corresponding first electrode and the second electrode on at least one of the first regions on the light spot so that the phase modulation depth of the first region is For the first modulation depth, there is a liquid crystal layer between the first electrode and the second electrode, and the liquid crystal layer is part of the liquid crystal on silicon.

FIG. 7 is a driving device 700 for liquid crystal on silicon disclosed in an embodiment of the application, which is applied to a wavelength selective switch including liquid crystal on silicon, on which an incident light beam enters and forms at least one light spot. The device includes: a communication interface 701 and a processor 702 coupled to the communication interface;

The processor 702 is used for:

A first voltage is applied to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and a second voltage is applied to at least one second area on the light spot to make the phase modulation depth of the second area The second modulation depth, the second modulation depth is greater than the first modulation depth.

FIG. 8 is a chip 800 disclosed in an embodiment of the application, which is used in a wavelength selective switch. An incident light beam is incident on the liquid crystal on silicon to form at least one light spot. The chip includes a memory 801 and a processor 802. 801 stores computer program instructions, and the processor 802 is used for the computer program instructions to make the chip execute any of the above-mentioned driving methods for liquid crystal on silicon.

The same and similar parts in the various embodiments in this application can be referred to each other. In particular, for the embodiments in FIG. 5 to FIG. 7, the description is relatively simple and related because it is based on the corresponding embodiment in FIG. 3 to FIG. 4b. For details, please refer to the part of the description of the corresponding embodiment in FIG. 3 to FIG. 4b.

The embodiment of the present application provides a computer-readable storage medium, including computer-readable instructions. When the computer reads and executes the above-mentioned computer-readable instructions, the computer is caused to execute the method executed by the above-mentioned processor.

The embodiment of the present application also provides a computer program product containing instructions, which when the computer program product runs on a computer, causes the computer to execute the method executed by the above-mentioned processor.

Obviously, those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general computing device, and they can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. Optionally, they can be implemented with program codes executable by the computing device, so that they can be stored in a storage medium (ROM/RAM, magnetic disk, optical disk) and executed by the computing device, and in some cases The steps shown or described can be performed in a different order from here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps of them can be fabricated into a single integrated circuit module for implementation. Therefore, the present invention is not limited to any specific combination of hardware and software.

Finally, it should be noted that the above are only specific implementations of this application, and the scope of protection of this application is not limited thereto. Any person skilled in the art can easily think of changes or changes within the technical scope disclosed in this application. Replacement shall be covered within the scope of protection of this application.

Claims

A driving method of liquid crystal on silicon, which is applied to a wavelength selective switch containing liquid crystal on silicon on which a light beam enters and forms at least one light spot, characterized in that the method includes:

A first voltage is applied to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and a second voltage is applied to at least one second area on the light spot to make the The phase modulation depth of the second region is a second modulation depth, the second modulation depth is greater than the first modulation depth, and the first modulation depth and the second modulation depth are used to modulate the light beam incident on the liquid crystal on silicon. Perform phase modulation.
The method according to claim 1, wherein there are one or more first regions between every two adjacent second regions.
The method according to claim 1 or 2, wherein the applying a first voltage to the at least one first area on the light spot makes the phase modulation depth of the first area a first modulation depth, comprising :

The first voltage is applied between the first electrode and the second electrode corresponding to the at least one first area on the light spot so that the phase modulation depth of the first area becomes the first modulation depth, and There is a liquid crystal layer between the first electrode and the second electrode;

The applying a second voltage to the at least one second area on the light spot to make the phase modulation depth of the second area a second modulation depth includes:

The second voltage is applied between the third electrode and the fourth electrode corresponding to the at least one second area on the light spot so that the phase modulation depth of the second area becomes the second modulation depth, and There is a liquid crystal layer between the third electrode and the fourth electrode.
The method according to claim 1 or 2, wherein the first modulation depth is 2π, and the second modulation depth is 4π.
A phase modulation device, applied to a wavelength selective switch, the phase modulation device comprising a silicon-based liquid crystal and a driving circuit, a light beam is incident on the silicon-based liquid crystal to form at least one light spot, and is characterized in that:

The driving circuit is configured to apply a first voltage to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth;

The driving circuit is also used to apply a second voltage to at least one second area on the light spot to make the phase modulation depth of the second area a second modulation depth, and the light spot includes the at least one first area and the For the at least one second region, the second modulation depth is greater than the first modulation depth, and the first modulation depth and the second modulation depth are used for phase modulation of the light beam.
The device according to claim 4, wherein there are one or more first regions between every two adjacent second regions.
The device according to claim 5 or 6, wherein the driving circuit comprises a first electrode and a second electrode,

The driving circuit is configured to apply a first voltage to the at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, which specifically includes:

The first voltage is applied between the first electrode and the second electrode corresponding to the at least one first area on the light spot so that the phase modulation depth of the first area is the first For modulation depth, there is a liquid crystal layer between the first electrode and the second electrode, and the liquid crystal layer is located on the liquid crystal on silicon.
A driving device for liquid crystal on silicon, applied to a wavelength selective switch containing liquid crystal on silicon, on which a light beam is incident to form at least one light spot, and is characterized in that it comprises: a communication interface and a communication interface coupled to the The processor of the communication interface;

The processor is used for:

A first voltage is applied to at least one first area on the light spot to make the phase modulation depth of the first area the first modulation depth, and a second voltage is applied to at least one second area on the light spot to make the The phase modulation depth of the second region is a second modulation depth. The second modulation depth is greater than the first modulation depth, and the first modulation depth and the second modulation depth are used to perform the beam incident on the liquid crystal on silicon. Phase modulation.
A chip is used in a wavelength selective switch containing liquid crystal on silicon. A light beam is incident on the liquid crystal on silicon to form at least one light spot. The chip is characterized in that the chip includes a memory and a processor, and the memory stores Computer program instructions, and the processor is used for the computer program instructions to make the chip execute any one of the methods in claims 1 to 4.