A wavelength selective switch, control method and optical communication system

Abstract

The embodiment of the application provides a wavelength selective switch, a control method and an optical communication system, relates to the technical field of optical communication, and is used for adjusting polarization-dependent loss of the wavelength selective switch. The wavelength selective switch comprises a fiber array and a spatial light modulator. The fiber array comprises input ports and output ports arranged along a first direction in a port plane. The spatial light modulator is used for loading a two-dimensional phase. The two-dimensional phase is used for deflecting input light signals incident through the input ports to the output ports and is used for adjusting an incident angle of the input light signals in a second direction when the input light signals are incident to the output ports. The second direction is in the port plane and is perpendicular to the first direction. The wavelength selective switch can be applied to optical communication.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a wavelength selective switch, control method and optical communication system. Background Technology

[0002] A wavelength selective switch (WSS) is an optical device that enables the switching of optical signals of different wavelengths between different fiber optic ports, playing a crucial role in optical communication networking. For example, it is widely used in optical switching fields such as reconfigurable optical add-drop multiplexers (ROADMs) and optical cross-connects (OXCs).

[0003] However, wavelength selective switches suffer from polarization dependent loss (PDL). Summary of the Invention

[0004] This application provides a wavelength selective switch, a control method, and an optical communication system for adjusting the polarization-dependent loss of the wavelength selective switch.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, a wavelength selective switch is provided, comprising an optical fiber array and a spatial light modulator. The optical fiber array includes an input port and an output port arranged in a port plane along a first direction. The spatial light modulator is used to load a two-dimensional phase, which is used to deflect an input optical signal incident through the input port to the output port and to adjust the incident angle of the input optical signal at the output port in a second direction; wherein the second direction is located in the port plane and is perpendicular to the first direction.

[0007] In the wavelength selective switch provided in this application, by loading a two-dimensional phase onto the spatial light modulator, the incident angle of the input optical signal at the output port in the second direction can be adjusted while achieving port switching; that is, the propagation path of the input optical signal in the dispersive plane optical path is changed when it is incident and emitted relative to the spatial light modulator. The change in the incident and emitted (relative to the spatial light modulator) path of the input optical signal in the dispersive plane optical path affects the polarization-dependent loss of the wavelength selective switch, thereby achieving the purpose of adjusting the polarization-dependent loss of the wavelength selective switch.

[0008] In one possible implementation, the wavelength selection switch further includes an intermediate optical component located between the fiber array and the spatial light modulator, which is divided into a port plane optical path and a dispersion plane optical path.

[0009] Two-dimensional phase is used to deflect the input optical signal in the port plane optical path and also in the dispersive plane optical path; the port plane optical path is used to convert the deflection of the input optical signal into a translation in the first direction, and the dispersive plane optical path is used to convert the deflection of the input optical signal into a change in the incident angle in the second direction when the input optical signal is incident on the output port.

[0010] In the wavelength selection switch provided in this application, the two-dimensional phase loaded on the spatial light modulator is used to deflect the input optical signal in the port plane optical path and to deflect the input optical signal in the dispersion plane optical path, thereby ensuring that the adjustment of polarization-dependent loss by the two-dimensional phase does not affect the port switching.

[0011] In one possible implementation, the dispersive plane optical path is used to split the input optical signal into a first beam and a second beam with orthogonal polarization states, convert the second beam to the same polarization state as the first beam, and project the first beam and the second beam to the same position of the spatial light modulator; wherein the first beam is polarized light that can be adjusted by the spatial light modulator.

[0012] Two-dimensional phase is used to deflect the first and second beams in the port plane optical path, and also to deflect the first and second beams in the dispersive plane optical path.

[0013] This design, based on port switching, alters the propagation paths of the first and second beams in the dispersive plane optical path when incident and emitted relative to the spatial light modulator using two-dimensional phase. This change in the incident and emitted paths (relative to the spatial light modulator) of the first and second beams in the dispersive plane optical path affects the polarization-dependent loss of the wavelength selective switch, thus enabling adjustment of the polarization-dependent loss of the wavelength selective switch.

[0014] In one possible implementation, the spatial light modulator includes a plurality of pixel units arranged in a third and a fourth direction, the pixel units being used for phase modulation.

[0015] The two-dimensional phase includes a first phase distributed in a third direction and a second phase distributed in a fourth direction. The first phase is used to deflect a first beam and a second beam in the port plane optical path, and the second phase is used to deflect a second beam and a second beam in the dispersive plane optical path.

[0016] In the wavelength selective switch provided in this application, the loading of a two-dimensional phase on the spatial light modulator can be achieved by a pixel array arranged in the third and fourth directions, which has a simple structure and good reliability.

[0017] In one possible implementation, the phase distribution of the second phase can be linear, quadratic, Gaussian, or trigonometric. In the wavelength selective switch provided in this application, different phase distributions can be used to adjust polarization-dependent loss, offering flexible and diverse solutions suitable for various applications.

[0018] In one possible implementation, the wavelength selection switch supports multiple wavelength channels, and the spatial light modulator includes multiple pixel regions arranged in a fourth direction. Each pixel region includes multiple pixel units arranged in a third direction and the fourth direction. The pixel units in different pixel regions are used to control the light signals in different wavelength channels.

[0019] The input optical signal is an optical signal in a wavelength channel, and the dispersive plane optical path is also used to project the input optical signal to the corresponding pixel area in the spatial light modulator according to the wavelength channel.

[0020] The wavelength selection switch provided in this application can support multiple wavelength channels, thus making it applicable to more application scenarios, such as wavelength division multiplexing (WDM) applications.

[0021] In one possible implementation, at least two of the second phases corresponding to different wavelengths of input optical signals are different. This design enables wavelength-level adjustment of polarization-dependent loss in multi-wavelength channel applications.

[0022] In one possible implementation, the second phase is the same as that corresponding to input optical signals of different wavelengths. This design allows for port-level adjustment of polarization-dependent loss in multi-wavelength channel applications.

[0023] In one possible implementation, the fiber array includes multiple output ports. A first phase is used to deflect the input optical signal to any one of the output ports. When the input optical signal of the same wavelength is deflected to different output ports, at least two of the second phases corresponding to the different output ports are different. This design allows for more precise adjustment of polarization-dependent loss for different wavelength channels and different output ports.

[0024] In one possible implementation, the dispersive plane optical path includes a polarization processing device, a second lens, a wave splitting and combining device, and a third lens arranged sequentially in the transmission direction from the fiber array to the spatial light modulator.

[0025] The polarization processing device includes a polarization beam splitter and a polarization conversion device. The polarization beam splitter is used to split the input optical signal into a first beam and a second beam with orthogonal polarization states. The polarization conversion device is used to convert the second beam into the same polarization state as the first beam.

[0026] The second and third lenses have the same focal length. The fiber array and the wave splitter / multiplexer are respectively set on the front and rear focal planes of the second lens, and the wave splitter / multiplexer and the spatial light modulator are respectively set on the front and rear focal planes of the third lens.

[0027] This design has advantages such as simple structure, easy implementation, and small footprint.

[0028] In one possible implementation, the port planar optical path includes a first lens, with the fiber array and spatial light modulator respectively positioned on the front and rear focal planes of the first lens. This design offers advantages such as simple structure, ease of implementation, and small footprint.

[0029] In one possible implementation, under the influence of the two-dimensional phase, the incident angle of the input optical signal at the input / output port in the second direction is less than or equal to 0.5 degrees. This design ensures that the adjustment of polarization-dependent loss by the two-dimensional phase does not affect port switching and reduces port loss of the input optical signal at the input / output port.

[0030] In one possible implementation, the spatial light modulator is a silicon-based liquid crystal. Silicon-based liquid crystals possess the characteristics of a flexible grid, supporting flexible adjustment of the bandwidth of the wavelength-selective switching channel. Alternatively, the spatial light modulator can also be a liquid crystal (LC) device, a micro-electro-mechanical system (MEMS) device, or other devices based on tunable electro-optic media.

[0031] Secondly, a control method for a wavelength selective switch is provided. The wavelength selective switch includes an optical fiber array and a spatial light modulator. The optical fiber array includes input ports and output ports arranged along a first direction in a port plane. The control method includes:

[0032] The input optical signal incident through the input port is projected onto the spatial light modulator;

[0033] The spatial light modulator is controlled to load a two-dimensional phase, which is used to deflect the input light signal incident through the input port to the output port and to adjust the incident angle in the second direction when the input light signal is incident on the output port.

[0034] The second direction is located in the port plane and is perpendicular to the first direction.

[0035] In one possible implementation, the wavelength selection switch further includes an intermediate optical component located between the fiber array and the spatial light modulator, which is divided into a port plane optical path and a dispersion plane optical path.

[0036] Two-dimensional phase is used to deflect input optical signals in port plane optical paths, and also in dispersive plane optical paths;

[0037] The port plane optical path is used to convert the deflection of the input optical signal into a translation in the first direction, and the dispersive plane optical path is used to convert the deflection of the input optical signal into a change in the incident angle in the second direction when the input optical signal is incident on the output port.

[0038] In one possible implementation, the input optical signal incident through the input port is projected onto the spatial light modulator, and the dispersive plane optical path includes:

[0039] Receives the input optical signal and splits the input optical signal into a first beam and a second beam with orthogonal polarization states;

[0040] Convert the second beam to the same polarization state as the first beam;

[0041] Both the first beam and the converted second beam are projected onto the same position of the spatial light modulator;

[0042] The first beam is polarized light that can be controlled by a spatial light modulator;

[0043] Two-dimensional phase is used to deflect the first and second beams in the port plane optical path, and also to deflect the second and second beams in the dispersive plane optical path.

[0044] In one possible implementation, the spatial light modulator includes a plurality of pixel units arranged in a third and a fourth direction, the pixel units being used for phase modulation.

[0045] The two-dimensional phase includes a first phase distributed in a third direction and a second phase distributed in a fourth direction. The first phase is used to deflect a first beam and a second beam in the port plane optical path, and the second phase is used to deflect a second beam and a second beam in the dispersive plane optical path.

[0046] In one possible implementation, the phase distribution of the second phase is a linear distribution, a quadratic distribution, a Gaussian distribution, or a trigonometric function distribution.

[0047] In one possible implementation, the wavelength selection switch supports multiple wavelength channels, and the input optical signal is the optical signal in one wavelength channel;

[0048] The spatial light modulator includes multiple pixel regions arranged in the fourth direction, and each pixel region includes multiple pixel units arranged in the third and fourth directions. The pixel units in different pixel regions are used to control light signals in different wavelength channels.

[0049] The input light signal incident through the input port is projected onto the spatial light modulator. The dispersive plane optical path also includes:

[0050] The input optical signal is projected onto the corresponding pixel area in the spatial light modulator according to the wavelength channel.

[0051] In one possible implementation, at least two of the second phases corresponding to input optical signals of different wavelengths are different.

[0052] In one possible implementation, the second phase is the same as that corresponding to input optical signals of different wavelengths.

[0053] In one possible implementation, the fiber array includes multiple output ports, and a first phase is used to deflect the input optical signal to any of the output ports for output.

[0054] When an input optical signal of the same wavelength is deflected to different output ports, at least two of the second phases corresponding to the different output ports are different.

[0055] In one possible implementation, under the action of two-dimensional phase, when the input optical signal is incident at the output port, the incident angle in the second direction is less than or equal to 0.5 degrees.

[0056] Thirdly, an optical communication system is provided, which includes a wavelength selective switch as described in any one of the first aspects and a transmission link. The transmission link is connected to the wavelength selective switch and is used to transmit optical signals input to the fiber array in the wavelength selective switch and to transmit optical signals output by the fiber array.

[0057] In one possible implementation, the optical communication system further includes a controller and a polarization-dependent loss detector, which is disposed in the transmission link and used to detect the polarization-dependent loss of the optical communication system.

[0058] The controller is electrically connected to a polarization-dependent loss detector and a wavelength selection switch, and is configured to adjust the two-dimensional phase recorded on the silicon-based liquid crystal based on the detection results of the polarization-dependent loss detector.

[0059] The control method and optical communication system provided in this application achieve the same technical effects as the wavelength selection switch in any of the above embodiments, and will not be repeated here. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the structure of a wavelength selective switch provided in an embodiment of this application;

[0061] Figure 2 This application provides a schematic diagram of the arrangement of an optical fiber array in a port plane according to an embodiment of the present application.

[0062] Figure 3 A front view of a silicon-based liquid crystal provided in an embodiment of this application;

[0063] Figure 4 for Figure 3 Cross-sectional view of a silicon-based liquid crystal;

[0064] Figure 5 for Figure 3 A diagram showing the relationship between pixel area and wavelength channel in a silicon-based liquid crystal.

[0065] Figure 6 for Figure 5 A schematic diagram illustrating the principle of forming the first blazed grating in the middle pixel region;

[0066] Figure 7 A schematic diagram of the wavelength selection switch in the port plane optical path provided in the embodiments of this application;

[0067] Figure 8 A schematic diagram of a wavelength selection switch provided in an embodiment of this application in a dispersive plane optical path;

[0068] Figure 9 Another schematic diagram of the wavelength selection switch provided in the embodiment of this application in a dispersive plane optical path;

[0069] Figure 10 A schematic diagram showing the positions of the beam waists of the first and second beams on a silicon-based liquid crystal, provided in an embodiment of this application.

[0070] Figure 11 Another schematic diagram of the wavelength selection switch provided in the embodiment of this application in a dispersive plane optical path;

[0071] Figure 12 for Figure 5 A schematic diagram illustrating the principle of forming the first and second blazed gratings in the middle pixel region;

[0072] Figure 13 Another schematic diagram of the wavelength selection switch provided in the embodiment of this application in a dispersive plane optical path;

[0073] Figure 14 A measured polarization-dependent loss diagram for a wavelength selective switch provided in this application embodiment;

[0074] Figure 15 Another measured diagram of polarization-dependent loss for a wavelength selective switch provided in this application embodiment;

[0075] Figure 16 Another measured diagram of polarization-dependent loss for a wavelength selective switch provided in this application embodiment;

[0076] Figure 17 A flowchart illustrating a control method for a wavelength selective switch provided in this application embodiment;

[0077] Figure 18 A schematic diagram of an optical communication system provided in an embodiment of this application;

[0078] Figure 19 This is a schematic diagram of another optical communication system provided in an embodiment of this application. Detailed Implementation

[0079] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0080] In the following embodiments of this application, the terms "first," "second," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0081] In the embodiments of this application, "upper", "lower", "left" and "right" are not limited to the orientation of the components in the accompanying drawings. It should be understood that these directional terms can be relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation of the components in the accompanying drawings.

[0082] In the embodiments of this application, unless the context otherwise requires, the term "comprising" is interpreted as open and encompassing throughout the specification and claims, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "exemplarily," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this application. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0083] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0084] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°; “equal” includes absolute equality and approximate equality, where an acceptable range of deviation for approximate equality may be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0085] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0086] Exemplary embodiments are described in this application with reference to cross-sectional views and / or plan views and / or equivalent circuit diagrams, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as being limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0087] This application provides a wavelength selective switch (WSS) that adopts a 1×N architecture. For example, N can be 9, 20, 32, 64, or 128, etc.; and supports multiple wavelength channels (λ1 to λ2). M M can be scheduled for optical signals such as 80, 96, 120 or 240.

[0088] like Figure 1 As shown, the wavelength selective switch 1 includes a fiber array 2, a silicon-based liquid crystal 4, and an intermediate optical component 3. Please also consider... Figure 2The fiber optic array 2 includes multiple fiber optic ports arranged along a first direction in a port plane. Here, the port plane refers to the distribution plane of the fiber optic ports in the fiber optic array 2, and the first direction is also called the port direction. In the fiber optic array 2, the multiple fiber optic ports include a first port D0 and multiple second ports (D1 to D2). N ); where the first port D0 is the COM port, i.e., the common port; the second port (D1 to D... N This is a non-COM port. In the first direction, the first port D0 can be located at any of the second ports (D1 to D2). N It can be located on one side of any two second ports (D1 to D) or on any two second ports (D1 to D). N )between.

[0089] In different operating scenarios of wavelength selective switch 1, the first port D0 and the second port (D1 to D2) of fiber array 2 N The functions of wavelength selection switch 1 differ. Specifically, the operating scenarios of wavelength selection switch 1 can be divided into upwave scenario and downwave scenario. In the downwave scenario, such as... Figure 1 As shown by the solid arrow, the input optical signal enters wavelength selection switch 1 through the first port D0. Wavelength selection switch 1 controls the input optical signal to pass through the second port (D1 to D2). N Output. This shows that in the next wave scenario, the first port D0 is used as the input port, and the second port (D1 to D2) is used as the output. N It is used as an output port.

[0090] In the previous scenario, such as Figure 1 As shown by the dashed arrow, the input optical signal passes through the second port (D1 to D2). N Entering wavelength selection switch 1, wavelength selection switch 1 controls the output of the input optical signal through the first port D0. Therefore, it can be seen that in the previous wave scenario, the second port (D1 to D0)... N ) is used as the input port, and the first port D0 is used as the output port.

[0091] In the wavelength selection switch 1 provided in this application embodiment, the input optical signal can be one wavelength channel (λ1 to λ2) supported by the wavelength selection switch 1. M The optical signal can be one of the wavelengths selected by the wavelength selection switch 1, i.e., a single-wavelength signal; or it can be a wavelength division multiplexing (WDM) signal supported by the wavelength selection switch 1, where the WDM signal is the optical signal of different wavelength channels (λ1 to λ2) supported by the wavelength selection switch 1. M It is formed by mixing two or more of the following. To facilitate understanding of the technical solution, unless otherwise specified, the input optical signal is a single-wavelength signal for illustrative purposes.

[0092] Please continue to refer to this. Figure 1 The wavelength selection switch 1 provided in this application embodiment also includes a silicon-based liquid crystal 4. The silicon-based liquid crystal 4 is a reflective diffraction grating that can be programmably implemented to achieve a specific phase distribution. Its main function is to control the emission angle of the input light signal by deflecting the input light signal.

[0093] Figure 3 A front view of a silicon-based liquid crystal 4 provided in an embodiment of this application, such as... Figure 3 As shown, the silicon-based liquid crystal 4 includes a pixel array, which comprises multiple pixel units 41 arranged in multiple rows and columns along a third and a fourth direction, wherein the third and fourth directions are perpendicular to each other. Figure 3 Taking the orientation shown as an example, the third direction is the vertical direction, and the fourth direction is the horizontal direction; the column direction in the pixel array is parallel to the third direction, and the row direction is parallel to the fourth direction.

[0094] Figure 4 for Figure 3 A cross-sectional view of a silicon-based liquid crystal 4, as shown below. Figure 4 As shown, the silicon-based liquid crystal 4 includes a silicon substrate 403, a transparent cover plate 401, and a liquid crystal layer 402. The silicon substrate 403 and the transparent cover plate 401 are disposed opposite to each other, and the liquid crystal layer 402 is disposed between the silicon substrate 403 and the transparent cover plate 401. The silicon substrate 403 has a reflective layer that can reflect incident light beams, and also has an array of pixel circuits. The pixel circuits include a first electrode 405 corresponding to a pixel unit 41. A second electrode 404 is disposed on the side of the transparent cover plate 401 near the silicon substrate 403.

[0095] For the silicon-based liquid crystal 4 using the above design, applying a voltage to the first electrode 405 and the second electrode 404 can control the deflection angle of the liquid crystal molecules located between the first electrode 405 and the second electrode 404 in the liquid crystal layer 402, that is, control the deflection angle of the liquid crystal molecules in the pixel unit 41. Due to the birefringence effect of the liquid crystal molecules, different deflection angles of the liquid crystal molecules can produce different phase retardation amounts. Therefore, by applying different voltages to the first electrode 405 and the second electrode 404, the purpose of phase modulation of the pixel unit 41 can be achieved.

[0096] By modulating the phase of pixel units 41 at different positions in the silicon-based liquid crystal 4, a structure similar to a blazed grating can be formed. A blazed grating can diffract and deflect incident input light signals. Since the diffraction and deflection angle of the input light signal by the blazed grating depends on the grating period, the diffraction and deflection angle of the input light signal can be controlled by simply loading different phase maps onto the silicon-based liquid crystal 4 and changing the grating period of the blazed grating formed by the silicon-based liquid crystal 4.

[0097] As described above, the wavelength selection switch 1 provided in this application embodiment supports multiple wavelength channels (λ1 to λ2). M The optical signal is scheduled. Based on this, such as... Figure 5 As shown, based on the multiple wavelength channels supported (λ1 to λ2), M The pixel array of the silicon-based liquid crystal 4 is divided into multiple pixel regions 42 in the fourth direction, and the multiple pixel regions 42 are connected to multiple wavelength channels (λ1 to λ2). M The number of pixels in each pixel region 42 is the same, and they have a one-to-one correspondence. Each pixel region 42 includes multiple pixel units 41 arranged in an array in the third and fourth directions. By controlling the pixel units 41 in each pixel region 42, the silicon-based liquid crystal 4 can form a separate blazed grating for the light signal of each wavelength channel, thereby achieving the purpose of separate diffraction and deflection of the light signal of each wavelength channel, which is beneficial to controlling the diffraction and deflection angle of the light signal of each wavelength channel.

[0098] In this embodiment, as Figure 6 As shown, the silicon-based liquid crystal 4 has a first phase 5 distributed along a third direction loaded in the pixel region 42, but no phase loaded in the fourth direction. The first phase 5 is used to form a first blazed grating, the grating direction of which is parallel to the third direction, enabling diffraction and deflection of the input light signal in the third direction. For ease of distinction, the diffraction deflection angle of the first blazed grating on the input light signal in the third direction is referred to as the first deflection angle.

[0099] In addition, since the silicon-based liquid crystal 4 does not load phase in the fourth direction, the silicon-based liquid crystal 4 can only reflect the input light signal in the fourth direction, which is equivalent to the function of a reflective mirror.

[0100] Please continue to refer to this. Figure 1 The wavelength selection switch 1 also includes an intermediate optical component 3, which is disposed between the silicon-based liquid crystal 4 and the fiber array 2, and is used to optically adjust the input optical signal transmitted between the silicon-based liquid crystal 4 and the fiber array 2. Depending on its function, the intermediate optical component 3 can be divided into a port plane optical path and a dispersion plane optical path.

[0101] Because some devices or apparatuses in the intermediate optical assembly 3 function in the port plane optical path but not in the dispersion plane optical path, and vice versa, some non-functional devices or apparatuses have been omitted in the description of the port plane optical path and dispersion plane optical path in the intermediate optical assembly 3 for ease of description and understanding.

[0102] Please refer to Figure 7In part (a) of this application, in the wavelength selection switch 1 provided in the embodiment of this application, for the input optical signal transmitted from the fiber array 2 to the silicon liquid crystal 4, the port planar optical path of the intermediate optical component 3 is used to project the input optical signal incident through different input ports onto the silicon liquid crystal 4 at different incident angles in a third direction. Please refer to Figure 7 In part (b), for the input optical signal transmitted from the silicon-based liquid crystal 4 to the fiber array 2, the port planar optical path of the intermediate optical component 3 is used to convert the different diffraction deflection angles (i.e. different first deflection angles) of the silicon-based liquid crystal 4 to the input optical signal in a third direction into translation along the first direction in the fiber array 2, that is, to convert the angle information into height information. Thus, by controlling the first deflection angle, the output port for outputting the input optical signal can be selected, thereby realizing the port switching function.

[0103] In this embodiment, as Figure 7 As shown, the port planar optical path can adopt a 2f optical system architecture, including a first lens 31; the fiber array 2 and the silicon-based liquid crystal 4 are located at the front and rear focal planes of the first lens 31, respectively.

[0104] Please refer to Figure 8 In part (a) of this application embodiment, in the wavelength selection switch 1, for the input optical signal transmitted from the fiber array 2 to the silicon-based liquid crystal 4, the dispersive plane optical path of the intermediate optical component 3 is used to select different wavelength channels ( Figure 8 The optical signals (taking λ1, λ2, and λ3 as examples) are projected into the corresponding pixel area 42 of the silicon-based liquid crystal 4. When the input optical signal is a wavelength division multiplexing (WDM) signal, the dispersive plane optical path is used to spatially separate the optical signals of different wavelength channels in the WDM signal and project the separated optical signals into the corresponding pixel area 42 of the silicon-based liquid crystal 4.

[0105] Please refer to Figure 8 In part (b), for the input optical signal transmitted from the silicon-based liquid crystal 4 to the fiber array 2, the dispersive plane optical path is also used to transmit different wavelength channels from the silicon-based liquid crystal 4. Figure 8 The optical signals (taking λ1, λ2, and λ3 as examples) are all projected onto the centerline of the port of fiber array 2 (please refer to...). Figure 2 On the optical fiber array 2, the centerline of the port is parallel to the first direction, and the centers of multiple optical fiber ports are all located on the centerline of this port. When optical signals from different wavelength channels are output from the same output port, the dispersive plane optical path can also combine the optical signals from different wavelength channels to form a wavelength division multiplexed signal, and then project the wavelength division multiplexed signal onto the centerline of the port of the optical fiber array 2.

[0106] In this embodiment, as Figure 8As shown, the dispersive plane optical path can adopt a 4f optical system architecture, including a second lens 32, a wave-splitting and combining device 33, and a third lens 34. The fiber array 2 is located at the front focal plane of the second lens 32, and the silicon-based liquid crystal 4 is located at the rear focal plane of the third lens 34. The second lens 32 and the third lens 34 have the same focal length, and the rear focal plane of the second lens 32 coincides with the front focal plane of the third lens 34. The wave-splitting and combining device 33 is located at this coincident position. The wave-splitting and combining device 33 is used to spatially separate optical signals from different wavelength channels and can also combine optical signals from different wavelength channels. For example, the wave-splitting and combining device 33 can be a diffraction grating.

[0107] Since the silicon-based liquid crystal 4 is a polarization-dependent element, it can only perform phase modulation on polarized light with a specific polarization state. Therefore, in the wavelength selection switch 1 of this application embodiment, the intermediate optical component 3 also includes a polarization processing device, which is located in the dispersive plane optical path and is used to perform polarization processing on the optical signal transmitted between the fiber array 2 and the wave splitter / combiner 33.

[0108] like Figure 9 As shown in part (a), the polarization processing device 37 includes a polarization beam splitter 35 and a polarization conversion device 36. During the transmission of the input optical signal from the fiber array 2 to the beam splitter / combiner 33, the polarization beam splitter 35 is used to polarize and split the input optical signal in the dispersive plane optical path, forming a first beam with orthogonal polarization states. Figure 9 (represented by dashed arrows) and the second beam ( Figure 9 (Indicated by solid arrows in the image), the first beam is polarized light matched to the silicon-based liquid crystal 4, that is, polarized light that the silicon-based liquid crystal 4 can modulate. The polarization conversion device 36 is used to convert the second beam to the same polarization state as the first beam, that is, to polarized light matched to the silicon-based liquid crystal 4. In this case, the silicon-based liquid crystal 4 can also modulate the second beam.

[0109] For example, the P-polarized light is modulated polarized light from the silicon-based liquid crystal 4; the first beam after being split by the polarization beam splitter 35 is P-polarized light, and the second beam is S-polarized light; the second beam is converted into P-polarized light after passing through the polarization conversion device 36. In this case, the polarization conversion device 36 can be a half-wave plate.

[0110] To facilitate understanding of the working principle of the wavelength selection switch 1 provided in this application embodiment, the following uses an optical signal with only one wavelength channel as an example to illustrate the working process of the wavelength selection switch 1 in the next wave scenario.

[0111] In the next wave scenario, the input optical signal enters the intermediate optical component 3 through the first port D0.

[0112] In a port-plane optical path, such as Figure 7 As shown in part (a), the first lens 31 projects the input light signal onto the center of the silicon liquid crystal 4 in the third direction.

[0113] In the dispersive plane optical path, please refer to Figure 9 In part (a), the polarization beam splitter 35 first polarizes the input optical signal into a first beam. Figure 9 (represented by dashed arrows) and the second beam ( Figure 9 (Represented by solid arrows in the image); where the first beam is P-polarized light and the second beam is S-polarized light, the P-polarized light being modulated polarized light by the silicon-based liquid crystal 4. Then, the polarization conversion device 36 converts the second beam to the same polarization state as the first beam, that is, converts the second beam from S-polarized light to P-polarized light; at this time, both the first and second beams are modulated polarized light by the silicon-based liquid crystal 4.

[0114] The first and second beams, after passing through the polarization processing device 37, are transmitted to the wave-splitting and combining device 33 via the second lens 32. The wave-splitting and combining device 33 projects the first and second beams onto the same position on the silicon-based liquid crystal 4, i.e., the same pixel area 42, through the third lens 34 according to their wavelengths. The beam waists of the first and second beams coincide on the silicon-based liquid crystal 4. Furthermore, the first and second beams are incident on the silicon-based liquid crystal 4 at an angle symmetrical in the fourth direction. From another perspective, when incident on the silicon-based liquid crystal 4, the first and second beams are distributed in a plane parallel to the fourth direction, and the center line of the distribution plane of the first and second beams is perpendicular to the fourth direction.

[0115] The silicon-based liquid crystal 4 is controlled to apply a first phase 5 in the third direction of the pixel region 42. The first phase 5 is used to form a first blazed grating. The first blazed grating produces the same diffraction deflection angle for the first beam and the second beam in the third direction. The silicon-based liquid crystal 4 acts as a reflective mirror for the first beam and the second beam in the fourth direction, reflecting the first beam and the second beam in the same way in the fourth direction.

[0116] After the first and second beams exit from the silicon-based liquid crystal 4, in the port plane optical path, as... Figure 7 As shown in part (b), the diffraction deflection angle of the first beam and the second beam in the third direction of the silicon-based liquid crystal 4 is converted into a translation in the first direction, thereby achieving the purpose of outputting in the output port corresponding to the first deflection angle.

[0117] After the first and second beams exit from the silicon-based liquid crystal 4, in the dispersive plane optical path, please refer to... Figure 9In part (b), the transmission path of the first beam coincides with the incident path of the second beam in the dispersive plane optical path, and the transmission path of the second beam coincides with the incident path of the first beam in the dispersive plane optical path.

[0118] As can be seen from the above description of the working process, during the incident and exit processes relative to the silicon-based liquid crystal 4, the propagation paths of the first beam and the second beam in the dispersive plane optical path completely overlap and exchange with each other, thus making the transmission efficiencies of the first beam and the second beam the same. Therefore, there is no difference in the insertion loss of input optical signals with different polarization states in the above optical path, that is, the polarization dependent loss (PDL) is zero.

[0119] However, it is difficult to achieve perfect performance for each component in wavelength selective switch 1, and the assembly and adjustment of each component may not be in the optimal state; this will cause degradation of polarization-dependent loss.

[0120] For example, such as Figure 10 As shown, the beam waists of the first and second beams, which should coincide on the silicon-based liquid crystal 4, will be misaligned, resulting in differences in the modulation of the first and second beams by the silicon-based liquid crystal 4. Consequently, the first and second beams will have different transmission paths in the dispersive plane optical path during incident and emanation processes relative to the silicon-based liquid crystal 4, leading to different transmission efficiencies. This, in turn, results in differences in the insertion loss of input light signals with different polarization states in the aforementioned optical path, generating polarization-dependent losses.

[0121] For example, such as Figure 11 As shown, the first beam ( Figure 11 (represented by dashed arrows) and the second beam ( Figure 11 (Indicated by solid arrows) When incident on the silicon-based liquid crystal 4, the incident angle in the fourth direction is asymmetrical. That is, when incident on the silicon-based liquid crystal 4, the center lines of the first and second beams on the distribution plane are tilted relative to the fourth direction. For ease of description, this paper refers to the center lines of the first and second beams on the distribution plane as the polarization beam splitting center lines. Figure 11 The polarization beam splitting centerline L2 is tilted relative to the fourth direction, meaning it is not perpendicular to the fourth direction.

[0122] Please continue to refer to this. Figure 11 When the polarization beam splitting center line L2 is tilted relative to the fourth direction, the first beam and the second beam will have different transmission paths in the dispersive plane optical path during the incident and emission processes relative to the silicon liquid crystal 4, resulting in different transmission efficiencies of the first beam and the second beam. Consequently, the insertion loss of input light signals with different polarization states in the above optical path will differ, resulting in polarization-dependent loss.

[0123] Furthermore, since the polarization beam splitting centerline L2 is tilted relative to the fourth direction when incident on the silicon-based liquid crystal 4, and since the dispersive plane optical path adopts a 4f optical system architecture, the input light signal emitted from the intermediate optical component 3 will have a certain tilt in the second direction when incident at the output port. For example... Figure 2 As shown, the second direction here is the direction perpendicular to the first direction in the port plane. That is to say, the input optical signal cannot enter the output port in a perpendicular orientation, thereby further degrading the polarization-dependent loss.

[0124] It can be seen that the wavelength selection switch 1 with the above design may have polarization-dependent loss problems.

[0125] Based on this, this application provides another wavelength selection switch 1, which differs from the wavelength selection switch 1 in the above embodiments in that, as Figure 12 As shown, during operation, the silicon-based liquid crystal 4 is controlled to load a two-dimensional phase 6, which is used to form a two-dimensional blazed grating. Specifically, the two-dimensional phase 6 includes a first phase 5 distributed in a third direction and a second phase 7 distributed in a fourth direction. The first phase 5 is used to form a first blazed grating, and the second phase 7 is used to form a second blazed grating. The grating direction of the first blazed grating is parallel to the third direction, and the grating direction of the second blazed grating is parallel to the fourth direction. For a description of the first phase 5 and the first blazed grating, please refer to the description in the above embodiments; it will not be repeated here.

[0126] like Figure 13 As shown, the second blazed grating is used to diffract and deflect the first and second beams in the fourth direction. For ease of distinction, the diffraction deflection angle of the first and second beams in the fourth direction by the second blazed grating is referred to as the second deflection angle. The second deflection angle can be adjusted by changing the second phase 7 to form second blazed gratings with different grating periods. As described above, the change in the second deflection angle can change the incident and exit paths of the first and second beams relative to the silicon liquid crystal 4 in the dispersive plane optical path. The change in the incident and exit paths of the first and second beams relative to the silicon liquid crystal 4 can alter the transmission efficiency of the first and second beams, thereby achieving the purpose of adjusting the polarization-dependent loss.

[0127] Since the dispersive plane optical path in the intermediate optical component 3 adopts a 4f optical system architecture, the deflection of the first and second beams in the fourth direction by the silicon-based liquid crystal 4 only causes a change in the incident angle in the second direction when the input optical signal enters the output port. For ease of description, this paper refers to the incident angle in the second direction when the input optical signal enters the output port as the dispersive incident angle. The change in the dispersive incident angle will not affect the switching port. Furthermore, according to the characteristics of the 4f optical system, the second deflection angle corresponds to the dispersive incident angle. By controlling the second deflection angle, the dispersive incident angle can be changed; thus, it is beneficial to make the input optical signal enter the output port in a vertical orientation (i.e., the dispersive incident angle is 0), further improving the problem of polarization-dependent loss.

[0128] To verify the effect of the wavelength selection switch 1 provided in this application embodiment on adjusting polarization-dependent loss, the following test was conducted in the downstream scenario of a C-band 120-wavelength (120 wavelength channels) product: a wavelength division multiplexing signal containing 120 wavelength channels was input through the first port D0, and the wavelength selection switch 1 was controlled to switch the optical signals in all 120 wavelength channels to the same second port (D1 to D2). N Output. During this process, a different two-dimensional phase 6 is applied to the optical signal of each wavelength channel to change the second phase 7, thereby generating different second deflection angles for the first and second beams. For different second deflection angles, the polarization-dependent loss of 120 wavelength channels is detected; the detection results are as follows: Figure 14 As shown.

[0129] exist Figure 14 In the diagram, Δθ represents the second deflection angle. The shaded area in the middle represents the detection results when no second phase 7 is applied, i.e., the second deflection angle Δθ is 0. To the left of this shaded area are the detection results when the second deflection angle Δθ is negative, and to the right are the detection results when the second deflection angle Δθ is positive. Furthermore, the further away from the shaded area, the larger the absolute value of the second deflection angle Δθ. Each small grid in the horizontal direction includes the polarization-dependent loss detection results for 120 wavelength channels under the same second deflection angle Δθ. Figure 14 As can be seen, the distribution of polarization-dependent loss across the 120 wavelength channels exhibits a parabolic trend under different second deflection angles Δθ. Therefore, by changing the second deflection angle Δθ, the polarization-dependent loss can be adjusted.

[0130] In some embodiments, such as Figure 13As shown, by adjusting the second deflection angle, the tilt angle of the polarization beam splitting center line L2 relative to the fourth direction when the first and second beams are incident on the silicon-based liquid crystal 4 can be compensated. This ensures that the transmission paths of the first and second beams in the dispersive plane optical path completely overlap and exchange during the incident and exit processes relative to the silicon-based liquid crystal 4. In this case, the transmission efficiency of the first and second beams is the same, therefore, there is no difference in the insertion loss of input optical signals with different polarization states in the above optical path; that is, the polarization-dependent loss is zero.

[0131] Furthermore, it enables the input optical signal to enter the input port at an angle perpendicular or nearly perpendicular to the second direction (i.e., the dispersive incident angle is 0 or close to 0) when incident at the output port. For example, under the influence of two-dimensional phase, the incident angle (i.e., the dispersive incident angle) of the input optical signal at the output port in the second direction is less than or equal to 0.5 degrees. This design can further improve polarization-dependent losses.

[0132] In other embodiments, the polarization-dependent loss of the wavelength selection switch 1 can be adjusted by adjusting the second deflection angle, so that the polarization-dependent loss of the wavelength selection switch 1 can compensate for the polarization-dependent loss generated by other optical devices in the optical communication system, thereby helping to reduce the overall polarization-dependent loss of the optical communication system.

[0133] The feasibility of adjusting polarization-related losses using wavelength selective switch 1 will be further explained below with specific examples.

[0134] In the next wave scenario of C-band 120-wave products, specifically for a certain second port (D1 to D...) N The optical signal output from a certain wavelength channel is used to detect the insertion loss (IL) of the first and second polarization states under different second deflection angles Δθ, and the insertion loss curves as a function of the second deflection angle Δθ are plotted. The first and second polarization states have the maximum transmission difference across all polarization states; that is, the polarization-dependent loss of wavelength selection switch 1 is the insertion loss difference between the first and second polarization states. The first and second polarization states are typically P-polarized light and S-polarized light, respectively. The detection results are as follows: Figure 15 As shown.

[0135] exist Figure 15 In the diagram, the difference in the ordinates of the two insertion loss curves corresponding to the same second deflection angle Δθ represents the polarization-dependent loss of wavelength selective switch 1 at that second deflection angle Δθ. From... Figure 15 As can be seen, by changing the second polarization angle Δθ, it is possible to control the polarization correlation loss to be 0 (the intersection of the two insertion loss curves), as well as to control the sign and magnitude of the polarization correlation loss.

[0136] In the above embodiments, the silicon-based liquid crystal 4 in the wavelength selective switch 1 can apply the same second phase 7 to optical signals of different wavelength channels output from the same output port, thereby enabling the adjustment of polarization-dependent loss for a specific output port and achieving port-level adjustment capability. However, the embodiments of this application are not limited to this.

[0137] In some embodiments, the silicon-based liquid crystal 4 in the wavelength selective switch 1 can load different second phases 7 for optical signals of different wavelength channels output from the same output port, that is, at least two of the second phases 7 loaded for optical signals of different wavelength channels are different; for example, all are different. With this design, polarization-dependent loss can be adjusted for optical signals of different wavelength channels output from the same output port, thereby achieving wavelength-level adjustment capability.

[0138] Figure 16 For C-band 120 waves (λ1 to λ) 120 In the next wave application scenario of the product, the polarization-dependent loss is compared for three schemes: no second phase loading, loading a second phase for port-level adjustment, and loading a second phase for wavelength-level adjustment. Figure 16 It can be seen that, compared to not loading the second phase, both schemes with the second phase significantly improve polarization-dependent loss. Furthermore, wavelength-level tuning significantly improves polarization-dependent loss compared to port-level tuning.

[0139] In some embodiments, the silicon-based liquid crystal 4 in the wavelength selective switch 1 can load different second phases 7 for optical signals of different wavelength channels output from the same output port. Furthermore, different second phases 7 can be loaded for optical signals of the same wavelength channel output from different output ports, meaning that at least two of the second phases 7 corresponding to different output ports are different; for example, all are different. This design allows for more refined polarization-dependent loss adjustment of the input optical signal, which is beneficial for further improving the performance of the wavelength selective switch 1.

[0140] In some embodiments, the phase distribution of the second phase 7 is a linear distribution, a quadratic distribution, a Gaussian distribution, or a trigonometric function distribution. This design is beneficial for adapting to different application scenarios.

[0141] In the above embodiments, the wavelength selective switch 1 uses silicon-based liquid crystal 4 as the spatial light modulator. The silicon-based liquid crystal 4 has the characteristic of a flexible grid, supporting flexible adjustment of the channel bandwidth of the wavelength selective switch 1. However, the embodiments of this application are not limited to this. The wavelength selective switch 1 provided in the embodiments of this application can also use a liquid crystal (LC) device, a micro-electro-mechanical system (MEMS) device, or other devices based on tunable electro-optic media as the spatial light modulator.

[0142] This application also provides a control method for a wavelength selective switch, applied to the wavelength selective switch 1 provided in the above embodiment, such as... Figure 17 As shown, the control method includes:

[0143] Step S10: Project the input light signal incident through the input port onto the spatial light modulator.

[0144] Step S20: Control the spatial light modulator to load a two-dimensional phase.

[0145] The two-dimensional phase is used to deflect the input optical signal to the output port and to adjust the incident angle of the input optical signal at the output port. The input port can be any port in the fiber array 2, and the output port can also be any port in the fiber array 2.

[0146] In some embodiments, the wavelength selection switch 1 further includes an intermediate optical component 3, which is located between the fiber array 2 and the spatial light modulator (e.g., a silicon-based liquid crystal 4), and is divided into a port plane optical path and a dispersion plane optical path.

[0147] Correspondingly, please see Figure 8 , Figure 12 and Figure 13 The two-dimensional phase 6 is used to deflect the input optical signal in the port plane optical path and also in the dispersive plane optical path; the port plane optical path is used to convert the deflection of the input optical signal into a translation in the first direction, and the dispersive plane optical path is used to convert the deflection of the input optical signal into a change in the incident angle in the second direction when the input optical signal is incident on the output port.

[0148] In some embodiments, please refer to Figure 9 Step S10 in the dispersive plane optical path includes:

[0149] Receives the input optical signal and splits the input optical signal into a first beam and a second beam with orthogonal polarization states;

[0150] Convert the second beam to the same polarization state as the first beam;

[0151] The first beam and the converted second beam are both projected onto the same position of the spatial light modulator (e.g., using a silicon-based liquid crystal 4);

[0152] The first beam is polarized light that can be controlled by a spatial light modulator (e.g., a silicon-based liquid crystal 4).

[0153] Correspondingly, please see Figure 7 and Figure 13 The two-dimensional phase 6 is used to deflect the first beam and the second beam in the port plane optical path, and also to deflect the second beam and the second beam in the dispersive plane optical path.

[0154] In some embodiments, the spatial light modulator (e.g., using a liquid crystal on silicon 4) includes a plurality of pixel units 41 arranged in a third and a fourth direction, the pixel units 41 being used for phase modulation. Correspondingly, the two-dimensional phase 6 includes a first phase 5 distributed in the third direction and a second phase 7 distributed in the fourth direction, the first phase 5 being used to deflect a first beam and a second beam in the port plane optical path, and the second phase 7 being used to deflect the second beam and the second beam in the dispersive plane optical path.

[0155] In some embodiments, the phase distribution of the second phase 7 is a linear distribution, a quadratic distribution, a Gaussian distribution, or a trigonometric function distribution.

[0156] In some embodiments, please refer to Figure 5 Wavelength selection switch 1 supports multiple wavelength channels (λ1 to λ2). M M can be, for example, 80, 96, 120 or 240, etc. The spatial light modulator (e.g., using a silicon-based liquid crystal 4) includes a plurality of pixel regions 42 arranged in a fourth direction. Each pixel region 42 includes a plurality of pixel units 41 arranged in a third direction and a fourth direction. The pixel units 41 in different pixel regions 42 are used to control light signals in different wavelength channels.

[0157] The input optical signal is an optical signal in one wavelength channel; correspondingly, step S10 in the dispersive plane optical path also includes:

[0158] The input optical signal is projected onto the corresponding pixel area 42 in the spatial light modulator (e.g., using a silicon-based liquid crystal 4) according to the wavelength channel.

[0159] In some embodiments, at least two of the second phases 7 corresponding to input optical signals of different wavelengths are different; or, the second phases 7 corresponding to input optical signals of different wavelengths are the same.

[0160] In some embodiments, the fiber array 2 includes multiple output ports, and a first phase 5 is used to deflect the input optical signal to any one of the output ports for output. When the input optical signal of the same wavelength is deflected to different output ports, at least two of the second phases 7 corresponding to the different output ports are different.

[0161] In some embodiments, under the action of two-dimensional phase 6, when the input optical signal is incident at the output port, the incident angle in the second direction is less than or equal to 0.5 degrees.

[0162] For further details on the control method, please refer to the description of wavelength selection switch 1 above, which will not be repeated here.

[0163] This application also provides an optical communication system 100, such as... Figure 18 As shown, the optical communication system 100 includes the wavelength selection switch 1 provided in the above embodiment; it also includes a transmission link 110 connected to the wavelength selection switch 1. The transmission link 110 is used to transmit optical signals input to the fiber array 2 in the wavelength selection switch 1, and is also used to transmit optical signals output by the fiber array 2.

[0164] As can be seen from the above description of wavelength selection switch 1, wavelength selection switch 1 can reduce its own polarization-dependent loss by adjusting polarization-dependent loss; it can also generate polarization-dependent loss to offset the polarization-dependent loss generated by other optical devices in optical communication system 100, thereby reducing the overall polarization-dependent loss of optical communication system 100.

[0165] Regarding the latter situation, such as Figure 18 As shown, the optical communication system 100 also includes a controller 130 and a polarization-dependent loss detector 120. The polarization-dependent loss detector 120 is disposed in the transmission link 110 and is used to detect the polarization-dependent loss of the optical communication system 120. The controller 130 is electrically connected to the polarization-dependent loss detector 120 and the wavelength selection switch 1, and is configured to adjust the polarization-dependent loss of the wavelength selection switch 1 according to the detection result of the polarization-dependent loss detector 120, thereby helping to reduce the overall polarization-dependent loss of the optical communication system 100.

[0166] The aforementioned optical communication system 100 can be any type of network architecture that uses wavelength selection switch 1 for networking, such as point-to-point network, ring network, MESH interconnection network, etc.

[0167] For example, such as Figure 19As shown, the optical communication system 100 includes multiple transmitters (Tx) 140 located at the transmitting end and multiple receivers (Rx) 160 located at the receiving end; it also includes a wavelength selection switch 1 and an optical amplifier (OA) 150 located between the transmitting end and the receiving end. The service optical signal is emitted from the transmitter 140 in the transmitting end, is amplified by the optical amplifier 150 after being scheduled by the wavelength selection switch 1, and is finally received by the receiver 160 in the receiving end.

[0168] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wavelength selective switch, characterized by, The wavelength selection switch includes: An optical fiber array, the optical fiber array including input ports and output ports arranged along a first direction in a port plane; and A spatial light modulator, wherein the spatial light modulator is used to load a two-dimensional phase, the two-dimensional phase being used to deflect an input light signal incident through the input port to the output port and to adjust the incident angle of the input light signal when it is incident on the output port in a second direction; The second direction is located in the port plane and is perpendicular to the first direction.

2. The wavelength selective switch of claim 1, wherein, The wavelength selection switch also includes an intermediate optical component, which is located between the fiber array and the spatial light modulator and is divided into a port plane optical path and a dispersion plane optical path. The two-dimensional phase is used to deflect the input optical signal in the port plane optical path, and also to deflect the input optical signal in the dispersive plane optical path; The port planar optical path is used to convert the deflection of the input optical signal into a translation in the first direction, and the dispersive plane optical path is used to convert the deflection of the input optical signal into a change in the incident angle in the second direction when the input optical signal is incident on the output port.

3. The wavelength selective switch of claim 2, wherein, The dispersive plane optical path is used to split the input optical signal into a first beam and a second beam with orthogonal polarization states, convert the second beam into the same polarization state as the first beam, and project the first beam and the second beam to the same position of the spatial light modulator; Wherein, the first beam is polarized light that can be controlled by the spatial light modulator; The two-dimensional phase is used to deflect the first beam and the second beam in the port plane optical path, and also to deflect the first beam and the second beam in the dispersive plane optical path.

4. The wavelength selective switch of claim 3, wherein, The spatial light modulator includes a plurality of pixel units arranged in a third and a fourth direction, the pixel units being used for phase modulation; The two-dimensional phase includes a first phase distributed in the third direction and a second phase distributed in the fourth direction. The first phase is used to deflect the first beam and the second beam in the port plane optical path, and the second phase is used to deflect the second beam and the second beam in the dispersive plane optical path.

5. The wavelength selective switch of claim 4, wherein, The phase distribution of the second phase can be linear, quadratic, Gaussian, or trigonometric.

6. The wavelength selective switch according to claim 4 or 5, characterized in that, The wavelength selection switch supports multiple wavelength channels, and the input optical signal is an optical signal from one of the wavelength channels. The spatial light modulator includes a plurality of pixel regions arranged in the fourth direction, and the pixel regions include a plurality of pixel units arranged in the third direction and the fourth direction. The pixel units in different pixel regions are used to control light signals in different wavelength channels. The dispersive plane optical path is also used to project the input optical signal onto the corresponding pixel region in the spatial light modulator according to the wavelength channel.

7. The wavelength selective switch of claim 6, wherein, In the second phase corresponding to the input optical signals of different wavelengths, at least two are different; Alternatively, the second phase may be the same as that corresponding to the input optical signal of a different wavelength.

8. The wavelength selective switch according to claim 6 or 7, characterized in that, The fiber array includes multiple output ports, and the first phase is used to deflect the input optical signal to any of the output ports for output. When the input optical signal of the same wavelength is deflected to different output ports, at least two of the second phases corresponding to the different output ports are different.

9. The wavelength selective switch according to any one of claims 6 to 8, characterized in that, The dispersive plane optical path includes a polarization processing device, a second lens, a wave splitting and combining device, and a third lens arranged sequentially in the transmission direction from the fiber array to the spatial light modulator. The polarization processing device includes a polarization beam splitter and a polarization conversion device. The polarization beam splitter is used to split the input optical signal into a first beam and a second beam with orthogonal polarization states. The polarization conversion device is used to convert the second beam into the same polarization state as the first beam. The second lens and the third lens have the same focal length. The fiber array and the wave splitter / multiplexer are respectively disposed on the front and rear focal planes of the second lens, and the wave splitter / multiplexer and the spatial light modulator are respectively disposed on the front and rear focal planes of the third lens.

10. The wavelength selective switch according to any one of claims 1 to 9, characterized in that, The port planar optical path includes a first lens, and the fiber array and the spatial light modulator are respectively disposed on the front and rear focal planes of the first lens.

11. The wavelength selective switch according to any one of claims 1 to 10, characterized in that, Under the influence of the two-dimensional phase, when the input optical signal is incident on the output port, the incident angle in the second direction is less than or equal to 0.5 degrees.

12. The wavelength selective switch according to any one of claims 1 to 11, characterized in that, The spatial light modulator is a silicon-based liquid crystal.

13. A control method for a wavelength selective switch, characterized in that, The wavelength selective switch includes an optical fiber array and a spatial light modulator, wherein the optical fiber array includes an input port and an output port arranged along a first direction in the port plane; The control method includes: The input optical signal incident through the input port is projected onto the spatial light modulator; The spatial light modulator is controlled to load a two-dimensional phase, which is used to deflect the input light signal incident through the input port to the output port and to adjust the incident angle of the input light signal when it is incident on the output port in a second direction. The second direction is located in the port plane and is perpendicular to the first direction.

14. The control method according to claim 13, characterized in that, The wavelength selection switch also includes an intermediate optical component, which is located between the fiber array and the spatial light modulator and is divided into a port plane optical path and a dispersion plane optical path. The two-dimensional phase is used to deflect the input optical signal in the port plane optical path, and also to deflect the input optical signal in the dispersive plane optical path; The port planar optical path is used to convert the deflection of the input optical signal into a translation in the first direction, and the dispersive plane optical path is used to convert the deflection of the input optical signal into a change in the incident angle in the second direction when the input optical signal is incident on the output port.

15. The control method according to claim 14, characterized in that, The process of projecting the input light signal incident through the input port onto the spatial light modulator includes, in the dispersive plane optical path: Receive the input optical signal and split the input optical signal into a first beam and a second beam with orthogonal polarization states; Convert the second beam to the same polarization state as the first beam; Both the first beam and the converted second beam are projected onto the same position of the spatial light modulator; Wherein, the first beam is polarized light that can be controlled by the spatial light modulator; The two-dimensional phase is used to deflect the first beam and the second beam in the port plane optical path, and also to deflect the second beam and the second beam in the dispersive plane optical path.

16. The control method according to claim 15, characterized in that, The spatial light modulator includes a plurality of pixel units arranged in a third and a fourth direction, the pixel units being used for phase modulation; The two-dimensional phase includes a first phase distributed in the third direction and a second phase distributed in the fourth direction. The first phase is used to deflect the first beam and the second beam in the port plane optical path, and the second phase is used to deflect the second beam and the second beam in the dispersive plane optical path.

17. The control method according to claim 16, characterized in that, The phase distribution of the second phase can be linear, quadratic, Gaussian, or trigonometric.

18. The control method according to claim 16 or 17, characterized in that, The wavelength selection switch supports multiple wavelength channels, and the input optical signal is an optical signal from one of the wavelength channels. The spatial light modulator includes a plurality of pixel regions arranged in the fourth direction, and the pixel regions include a plurality of pixel units arranged in the third direction and the fourth direction. The pixel units in different pixel regions are used to control light signals in different wavelength channels. The process of projecting the input light signal incident through the input port to the spatial light modulator further includes, in the dispersive plane optical path: The input optical signal is projected onto the corresponding pixel region in the spatial light modulator according to the wavelength channel.

19. The control method according to claim 18, characterized in that, In the second phase corresponding to the input optical signals of different wavelengths, at least two are different; Alternatively, the second phase may be the same as that corresponding to the input optical signal of a different wavelength.

20. The control method according to claim 18 or 19, characterized in that, The fiber array includes multiple output ports, and the first phase is used to deflect the input optical signal to any of the output ports for output. When the input optical signal of the same wavelength is deflected to different output ports, at least two of the second phases corresponding to the different output ports are different.

21. The control method according to any one of claims 13 to 20, characterized in that, Under the influence of the two-dimensional phase, when the input optical signal is incident on the output port, the incident angle in the second direction is less than or equal to 0.5 degrees.

22. An optical communication system, characterized in that, The optical communication system includes: Wavelength selective switch as claimed in any one of claims 1 to 12; The transmission link is connected to the wavelength selection switch and is used to transmit optical signals input to the fiber array in the wavelength selection switch, and also to transmit optical signals output by the fiber array.

23. The optical communication system according to claim 22, characterized in that, The optical communication system also includes a controller and a polarization-dependent loss detector, wherein the polarization-dependent loss detector is disposed in the transmission link and is used to detect the polarization-dependent loss of the optical communication system; The controller is electrically connected to the polarization-dependent loss detector and the wavelength selection switch, and is configured to adjust the two-dimensional phase recorded on the silicon-based liquid crystal according to the detection result of the polarization-dependent loss detector.

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