A wavelength selective switch

Abstract

The application discloses a wavelength selective switch for improving the stability of signal transmission. Signal light input ports and dummy light input ports are distributed along a first direction. A first dispersion element is used to decompose signal light from the signal light input ports into a plurality of sub-wavelength signal lights in a second direction, and to decompose dummy light from the dummy light input ports into a plurality of sub-wavelength dummy lights in the second direction. The second direction is perpendicular to the first direction. A first optical switch array is used to adjust the deflection direction of the plurality of sub-wavelength signal lights. The sub-wavelength signal lights and the sub-wavelength dummy lights of the same wavelength have the same incident position on a second optical switch array. The second optical switch array is used to adjust the deflection direction of the incident light at each incident position, so that the sub-wavelength signal light or the sub-wavelength dummy light of each wavelength is transmitted to an output port. It is equivalent to that the sub-wavelength signal light and the sub-wavelength dummy light of each wavelength are selected by the second optical switch array, and the selected light is transmitted to the output port.

Description

Technical Field

[0001] This application relates to the field of optical communication, and more particularly to a wavelength selective switch. Background Technology

[0002] With the rapid growth of data traffic on networks, the demand for network transmission capacity is also increasing. Network transmission capacity can usually be improved by increasing the channel operating spectrum bandwidth (number of channels), for example, by expanding the original C-band to include both C-band and L-band.

[0003] However, with the increase of channel bandwidth, stimulated Raman scattering (SRS) occurs in multi-wavelength transmission system links, causing a transfer of transmission power from short-wavelength bands to long-wavelength bands. In a steady state without upswing or downswing, the power transfer between multi-wavelength signals caused by the SRS effect is stable. However, when upswing or downswing occurs, the number, distribution, and location of the multi-wavelength signals change randomly, leading to complex variations in the SRS effect. This can potentially exceed the system's capacity, thus reducing the stability of signal transmission. Summary of the Invention

[0004] This application provides a wavelength selective switch (WSS) to improve the stability of signal transmission.

[0005] In a first aspect, this application provides a wavelength selective switch. The wavelength selective switch includes: a signal light input port, a dummy light input port, an output port, a first dispersive element, a second dispersive element, a first optical switch array, a second optical switch array, a first mirror group, a second mirror group, and a third mirror group. The signal light input port and the dummy light input port are distributed along a first direction.

[0006] A first dispersive element is used to decompose the signal light from the signal light input port into multiple sub-wavelength signal lights in a second direction, and to decompose the dummy light from the dummy light input port into multiple sub-wavelength dummy lights in the second direction. The second direction is perpendicular to the first direction. A first mirror group is used to collimate the multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights in the second direction. A first optical switch array is used to adjust the deflection direction of the multiple sub-wavelength signal lights from the first lens. A second mirror group is used to guide the sub-wavelength signal lights from the first optical switch array and the sub-wavelength dummy lights from the first mirror group to the second optical switch array. Sub-wavelength signal lights and sub-wavelength dummy lights of the same wavelength have the same incident position on the second optical switch array. The second optical switch array is used to adjust the deflection direction of the incident light at each incident position so that each wavelength of sub-wavelength signal light or sub-wavelength dummy light is transmitted to the output port. A third mirror group is used to converge the sub-wavelength signal lights and / or sub-wavelength dummy lights from the second optical switch array in the second direction. The second dispersive element is used to combine the sub-wavelength signal light and / or sub-wavelength dummy light from the third mirror group and guide the combined light to the output port.

[0007] In this embodiment, even if a signal light of a certain wavelength is dropped during transmission, a dummy light of that wavelength can be selected by the second optical switch array to fill the channel of the dropped signal light, thereby maintaining a full-wavelength state, stabilizing the SRS effect, and improving the stability of signal transmission. Furthermore, using the second optical switch array only requires switching between two output directions, resulting in faster adjustment and enabling rapid uploading of both signal light and dummy light.

[0008] In some possible implementations, if the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the second optical switch array is greater than or equal to a preset value, then the first sub-wavelength dummy light incident at the first incident position is transmitted to the output port through the second optical switch array. If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the second optical switch array is less than the preset value, then the first sub-wavelength signal light is transmitted to the output port through the second optical switch array.

[0009] In this embodiment, by detecting the energy of the incident sub-wavelength signal light on the second optical switch array, the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength can be reasonably selected, so that the normally transmitted sub-wavelength signal light can continue to transmit, and the abnormally transmitted sub-wavelength signal light can be ensured to be in full-wavelength state by uploading the sub-wavelength dummy light.

[0010] In some possible implementations, multiple sub-wavelength dummy lights from the first mirror group are transmitted to the second mirror group via a first optical switch array. That is, the first optical switch array can also adjust the deflection direction of the incident sub-wavelength dummy lights, expanding the application scenarios of this solution.

[0011] In some possible implementations, the first optical switch array is also used to adjust the deflection direction of the second sub-wavelength dummy light from the first mirror group. The second sub-wavelength dummy light, after deflection direction adjustment, is not guided to the second optical switch array. The second optical switch array is used to adjust the deflection direction of the second sub-wavelength signal light from the second mirror group to attenuate the energy transmitted by the second sub-wavelength signal light to the output port. The second sub-wavelength dummy light has the same wavelength as the second sub-wavelength signal light. In this implementation, before attenuating the second sub-wavelength signal light through the second optical switch array, the second sub-wavelength dummy light needs to be blocked by the first optical switch array to avoid enhancing the second sub-wavelength dummy light while attenuating the second sub-wavelength signal light, thus ensuring the attenuation effect.

[0012] In some possible implementations, the third sub-wavelength signal light, after being deflected by the first optical switch array, is not guided to the second optical switch array. The second optical switch array is used to adjust the deflection direction of the third sub-wavelength dummy light from the second mirror group to attenuate the energy transmitted by the dummy light to the output port. The dummy light has the same wavelength as the third sub-wavelength signal light. In this implementation, before attenuating the dummy light by the second optical switch array, the third sub-wavelength signal light must first be blocked by the first optical switch array to avoid simultaneously attenuating the dummy light and enhancing the third sub-wavelength signal light, thus ensuring the attenuation effect.

[0013] In some possible implementations, the WSS further includes a fourth mirror group and a fifth mirror group. The fourth mirror group is used to collimate and shape the signal light from the signal light input port before guiding it to the first dispersive element, and to collimate and shape the dummy light from the dummy light input port before guiding it to the first dispersive element. The fifth mirror group is used to collimate and shape the combined light from the second dispersive element before guiding it to the output port. Through this method, collimation and beam shaping can be performed on the light before dispersion and after combining, enhancing the practicality of this solution.

[0014] In some possible implementations, the first lens group includes a first lens, a second lens, and a third lens. The first lens is used to transmit multiple sub-wavelength signal light from the first dispersive element, or to refract the multiple sub-wavelength signal light from the first dispersive element in a first direction. The second lens is used to transmit multiple sub-wavelength dummy light from the first dispersive element, or to refract the multiple sub-wavelength dummy light from the first dispersive element in a first direction. The third lens is used to collimate the multiple sub-wavelength signal light from the first lens in a second direction and to collimate the multiple sub-wavelength dummy light from the second lens. This provides a specific implementation of the first lens group, improving the feasibility of this solution. In scenarios with multiple signal light input ports, the first lens can focus multiple signal lights to the same position of the first optical switch array in the first direction, and the second lens can guide the dummy light to other positions of the first optical switch array in the first direction.

[0015] In some possible implementations, the second mirror group includes a fourth lens, a fifth lens, and a sixth lens. The fourth lens is used to converge the sub-wavelength signal light from the first optical switch array in a second direction, and to converge the sub-wavelength dummy light from the first mirror group. The fifth lens is used to converge the sub-wavelength signal light and the sub-wavelength dummy light from the fourth lens in a first direction. The sixth lens is used to collimate and guide the sub-wavelength signal light and the sub-wavelength dummy light from the fifth lens in a second direction to the second optical switch array. This provides a specific implementation of the second mirror group, improving the feasibility of this solution.

[0016] In some possible implementations, the third mirror group includes a seventh lens and an eighth lens. The seventh lens is used to converge the sub-wavelength signal light from the second optical switch array in the second direction, and to converge the sub-wavelength dummy light from the second optical switch array. The eighth lens is used to perform beam shaping on the sub-wavelength signal light and the sub-wavelength dummy light from the seventh lens. This provides a specific implementation of the third mirror group, improving the feasibility of this solution.

[0017] In some possible implementations, the first optical switch array is a liquid crystal on silicon (LCOS), and the second optical switch array is a digital light processor (DLP). It should be understood that LCOS can support adjustment of any deflection direction, making it more widely applicable. DLP typically only supports two deflection directions, allowing for faster polarization direction switching.

[0018] In some possible implementations, the WSS also includes a controller, which controls the first optical switch array and the second optical switch array to facilitate wavelength selection of the first optical switch array according to actual conditions, and to select between sub-wavelength signal light and sub-wavelength dummy light of the same wavelength according to actual conditions.

[0019] Secondly, this application provides a wavelength selective switch. The wavelength selective switch includes: a signal light input port, a dummy light input port, an output port, a first dispersion element, a second dispersion element, an optical switch array, a first polarization conversion device, a second polarization conversion device, a polarization combiner, a polarization conversion array, a polarization separator, a first mirror group, a second mirror group, and a third mirror group. The signal light input port and the dummy light input port are distributed along a first direction.

[0020] A first polarization conversion device converts the signal light from the signal light input port into a first polarization state. A second polarization conversion device converts the dummy light from the dummy light input port into a second polarization state. The first and second polarization states are orthogonal to each other. A first dispersive element decomposes the signal light from the first polarization conversion device into multiple sub-wavelength signal lights in a second direction, and decomposes the dummy light from the second polarization conversion device into multiple sub-wavelength dummy lights in the second direction. The second direction is perpendicular to the first direction. A first mirror group collimates the multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights in the second direction. An optical switch array adjusts the deflection direction of the multiple sub-wavelength signal lights from the first lens. A second mirror group guides the sub-wavelength signal lights from the optical switch array and the sub-wavelength dummy lights from the first mirror group to a polarization combiner. The polarization combiner combines the sub-wavelength signal lights and sub-wavelength dummy lights from the second mirror group and guides the combined sub-wavelength signal lights and sub-wavelength dummy lights to a polarization conversion array. Sub-wavelength signal lights and sub-wavelength dummy lights of the same wavelength have the same incident position on the polarization conversion array. A polarization conversion array is used to adjust the polarization state of the incident light at each incident position to select the polarization state of each sub-wavelength signal light and each sub-wavelength dummy light output from the polarization conversion array. Specifically, sub-wavelength signal light and sub-wavelength dummy light of the same wavelength output from the polarization conversion array have different polarization states. A polarization splitter is used to transmit sub-wavelength signal light and / or sub-wavelength dummy light with a first polarization state from the polarization conversion array and to reflect sub-wavelength signal light and / or sub-wavelength dummy light with a second polarization state from the polarization conversion array. A third mirror group is used to converge the sub-wavelength signal light and / or sub-wavelength dummy light transmitted by the polarization splitter in a second direction. A second dispersive element is used to combine the sub-wavelength signal light and / or sub-wavelength dummy light from the third mirror group and guide the combined light to the output port.

[0021] In this embodiment, even if a signal light of a certain wavelength is dropped during transmission, a dummy light of that wavelength can be selected using a polarization conversion array and a deflection separator to fill the channel of the dropped signal light, thereby maintaining a full-wavelength state, stabilizing the SRS effect, and improving the stability of signal transmission. Furthermore, using a polarization conversion array only requires switching the incident light between two polarization states, resulting in faster adjustment and enabling rapid uploading of both signal light and dummy light.

[0022] In some possible implementations, if the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the polarization conversion array is greater than or equal to a preset value, then the first sub-wavelength dummy light incident at the first incident position has a first polarization state after passing through the polarization conversion array, and the first sub-wavelength signal light has a second polarization state after passing through the polarization conversion array. If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the polarization conversion array is less than a preset value, then the first sub-wavelength dummy light has a second polarization state after passing through the polarization conversion array, and the first sub-wavelength signal light has a first polarization state after passing through the polarization conversion array.

[0023] In this embodiment, by detecting the energy of the incident sub-wavelength signal light on the polarization conversion array, sub-wavelength signal light and sub-wavelength dummy light of the same wavelength can be reasonably selected, so that the normally transmitted sub-wavelength signal light can continue to transmit, and for the abnormally transmitted sub-wavelength signal light, sub-wavelength dummy light can be uploaded to ensure that the light after passing through WSS is in full-wavelength state.

[0024] In some possible implementations, multiple sub-wavelength dummy beams from the first mirror group are transmitted to the second mirror group via an optical switch array. That is, the optical switch array can also adjust the deflection direction of the incident sub-wavelength dummy beams, expanding the application scenarios of this solution.

[0025] In some possible implementations, the optical switch array is also used to adjust the deflection direction of the second sub-wavelength dummy light from the first mirror group, wherein the second sub-wavelength dummy light, after deflection direction adjustment, does not guide the polarization combiner. The polarization conversion array is used to adjust the polarization state of the second sub-wavelength signal light from the polarization combiner to attenuate the energy transmitted by the second sub-wavelength signal light to the output port. The second sub-wavelength dummy light has the same wavelength as the second sub-wavelength signal light. In this implementation, before attenuating the second sub-wavelength signal light through the polarization conversion array, the second sub-wavelength dummy light needs to be blocked by the optical switch array to avoid enhancing the second sub-wavelength dummy light while attenuating the second sub-wavelength signal light, thus ensuring the attenuation effect.

[0026] In some possible implementations, the third sub-wavelength signal light, after its deflection direction is adjusted by the optical switch array, is not guided to the polarization combiner. The polarization conversion array is used to adjust the polarization state of the third sub-wavelength dummy light from the polarization combiner to attenuate the energy transmitted by the dummy light to the output port. The dummy light has the same wavelength as the third sub-wavelength signal light. In this implementation, before attenuating the dummy light via the polarization conversion array, the third sub-wavelength signal light must first be blocked by the optical switch array to avoid simultaneously attenuating the dummy light and enhancing the third sub-wavelength signal light, thus ensuring the attenuation effect.

[0027] In some possible implementations, the WSS further includes a fourth mirror group and a fifth mirror group. The fourth mirror group is used to collimate and shape the signal light from the signal light input port before guiding it to the first polarization conversion device, and to collimate and shape the dummy light from the dummy light input port before guiding it to the first polarization conversion device. The fifth mirror group is used to collimate and shape the light after it has been combined from the second dispersive element before guiding it to the output port. Through this method, collimation and beam shaping can be performed on the light before dispersion and after combining, enhancing the practicality of this solution.

[0028] In some possible implementations, the first lens group includes a first lens, a second lens, and a third lens. The first lens is used to transmit multiple sub-wavelength signal light from the first dispersive element, or to refract the multiple sub-wavelength signal light from the first dispersive element in a first direction. The second lens is used to transmit multiple sub-wavelength dummy light from the first dispersive element, or to refract the multiple sub-wavelength dummy light from the first dispersive element in a first direction. The third lens is used to collimate the multiple sub-wavelength signal light from the first lens in a second direction and to collimate the multiple sub-wavelength dummy light from the second lens. This provides a specific implementation of the first lens group, improving the feasibility of this solution. In scenarios with multiple signal light input ports, the first lens can focus multiple signal lights to the same position on the optical switch array in the first direction, and the second lens can guide the dummy light to other positions on the optical switch array in the first direction.

[0029] In some possible implementations, the second mirror group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and a reflector. The fourth lens is used to converge the sub-wavelength signal light from the optical switch array in a second direction and to converge the sub-wavelength dummy light from the first mirror group. The fifth lens is used to perform beam shaping on the sub-wavelength signal light from the fourth lens. The sixth lens is used to collimate the sub-wavelength signal light from the fifth lens in a second direction and guide it to the polarization combiner. The seventh lens is used to perform beam shaping on the sub-wavelength dummy light from the fourth lens. The reflector is used to reflect the sub-wavelength dummy light from the seventh lens to the polarization combiner. This provides a specific implementation of the second mirror group, improving the feasibility of this solution.

[0030] In some possible implementations, the third mirror group includes an eighth lens and a ninth lens. The eighth lens is used to converge the sub-wavelength signal light from the polarization separator and the sub-wavelength dummy light from the polarization separator in the second direction. The ninth lens is used to perform beam shaping on the sub-wavelength signal light and the sub-wavelength dummy light from the eighth lens. This provides a specific implementation of the third mirror group, improving the feasibility of this solution.

[0031] In some possible implementations, the optical switch array is an LCOS, and the polarization conversion array is a ferroelectric liquid crystal on silicon (F-LCOS). It should be understood that LCOS can support adjustment of any deflection direction, thus having a wider range of applications. F-LCOS typically only supports two polarization states, allowing for faster polarization state switching.

[0032] In some possible implementations, the WSS also includes a controller, with the optical switch array and polarization conversion array controlled by the controller. This allows for wavelength selection by controlling the optical switch array according to actual conditions, and for adjusting the polarization state of the incident light by controlling the polarization conversion array according to actual conditions. It also combines a polarization separator to perform a two-way selection between sub-wavelength signal light and sub-wavelength dummy light of the same wavelength.

[0033] In this embodiment, the WSS has a signal light input port and a dummy light input port, where the dummy light is a beam that does not carry information. The signal light and dummy light undergo dispersion after passing through a dispersive element, thus decomposing into multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights. The function of the first optical switch array is to adjust the deflection direction of the multiple sub-wavelength signal lights to select the sub-wavelength signal light to be transmitted to the second optical switch array. Sub-wavelength signal lights and sub-wavelength dummy lights of the same wavelength have the same incident position on the second optical switch array. The function of the second optical switch array is to adjust the deflection direction of the incident light at each incident position, thereby performing a two-way selection between each wavelength's sub-wavelength signal light and sub-wavelength dummy light. The selected sub-wavelength signal light or sub-wavelength dummy light can be transmitted to the output port. In this way, even if a certain wavelength of signal light drops during transmission, the second optical switch array can select the dummy light of that wavelength to achieve uploading dummy light, filling the channel of the dropped signal light, thus maintaining a full-wavelength state, stabilizing the SRS effect, and improving the stability of signal transmission. In addition, using a second optical switch array only requires switching between two output directions, which allows for faster adjustment and enables rapid uploading of signal light and dummy light. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an optical transmission system used in an embodiment of this application; Figure 2(a) is a schematic diagram of the first optical path of WSS in the dispersion direction in the embodiment of this application; Figure 2(b) is a schematic diagram of the first optical path of WSS in the port direction in the embodiment of this application; Figure 3(a) is a schematic diagram of the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the first optical switch array; Figure 3(b) is a schematic diagram of the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the second optical switch array; Figure 4(a) is a schematic diagram of the second optical path of WSS in the dispersion direction in an embodiment of this application; Figure 4(b) is a schematic diagram of the second optical path of WSS in the port direction in the embodiment of this application; Figure 5(a) is a schematic diagram of the third optical path of WSS in the dispersion direction in the embodiment of this application; Figure 5(b) is a schematic diagram of the third optical path of WSS in the port direction in the embodiment of this application; Figure 6(a) is a schematic diagram of the fourth optical path of WSS in the dispersion direction in the embodiment of this application; Figure 6(b) is a schematic diagram of the fourth optical path of WSS in the port direction in the embodiment of this application. Detailed Implementation

[0035] This application provides a Wavelength Selective Switch (WSS) that can maintain a full-wavelength state by rapidly uploading dummy light to fill the channel of the signal light that has lost wavelength, thus stabilizing the SRS effect and improving the stability of signal transmission. The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] Figure 1 This is a schematic diagram of an optical transmission system used in an embodiment of this application. Figure 1 As shown, the optical transmission system includes optical amplifier 1, optical amplifier 2, wavelength selective switch 1, wavelength selective switch 2, add-drop wavelength selective switch (ADWSS) 1, and add-drop wavelength selective switch 2. It should be understood that to ensure SRS stability, the channel should be in a full-wave state. The light transmitted on the channel can include signal light and dummy light, where dummy light is light that does not carry a signal. That is, some idle channels without transmitted signal light can be filled with dummy light. As an example, the light passing through optical amplifier 1 is in a full-wave state, where the wavelength of the signal light is λ1-λ4, and the wavelengths of the dummy light are λ5 and λ6. After the full-wave light passes through wavelength selective switch 1, the signal light with wavelength λ1 is downloaded to add-drop wavelength selective switch 1. Furthermore, the dummy light with wavelengths λ5 and λ6 is blocked by wavelength selective switch 1, and add-drop wavelength selective switch 2 then uploads the signal light with wavelengths λ5 and λ6 to wavelength selective switch 2. Furthermore, the wavelength selection switch 2 will also carry a dummy light with a carrier length λ1, so that the light output from the wavelength selection switch 2 to the optical amplifier 2 is still in a full-wave state.

[0037] Based on the above description, when certain wavelengths of light are suddenly passively dropped due to factors such as laser source damage or optical amplifier failure, the WSS needs to be able to quickly upload dummy light to fill the channels of these dropped signals, minimizing signal power fluctuations and damage caused by transient effects or SRS effects of the optical amplifier. The WSS provided in the embodiments of this application will be described in detail below.

[0038] For ease of explanation, in the following embodiments, the direction of light transmission is uniformly defined as the Z-direction, the direction of port distribution is defined as the X-direction, and the direction of light dispersion is defined as the Y-direction. The X-direction is perpendicular to the Z-direction, the Y-direction is perpendicular to the Z-direction, and the X-direction is perpendicular to the Y-direction. Furthermore, this application does not limit the number of signal light input ports, dummy light input ports, and output ports; the numbers shown in the accompanying drawings are merely examples.

[0039] Figure 2(a) is a schematic diagram of the first optical path of the WSS in the dispersion direction in an embodiment of this application. Figure 2(b) is a schematic diagram of the first optical path of the WSS in the port direction in an embodiment of this application. As shown in Figures 2(a) and 2(b), the wavelength selective switch includes: a signal light input port 10, a dummy light input port 20, a first dispersion element 30, a first optical switch array 40, a second optical switch array 50, a second dispersion element 60, an output port 70, a mirror group 1, a mirror group 2, and a mirror group 3. The signal light input port 10 and the dummy light input port 20 are distributed in the X direction. Optionally, the wavelength selective switch may further include a mirror group 4 and a mirror group 5.

[0040] Specifically, mirror group 4 is used to collimate and shape the signal light from signal light input port 10 before guiding it to the first dispersive element 30, and to collimate and shape the dummy light from dummy light input port 20 before guiding it to the first dispersive element 30. The first dispersive element 30 is used to decompose the signal light from signal input port 10 into multiple sub-wavelength signal lights in the Y direction, and to decompose the dummy light from dummy light input port 20 into multiple sub-wavelength dummy lights in the Y direction. The wavelengths of the multiple sub-wavelength signal lights and the multiple sub-wavelength dummy lights are all different. Mirror group 1 is used to collimate the multiple sub-wavelength signal lights and the multiple sub-wavelength dummy lights in the Y direction to convert the angular difference in the wavelength direction into a positional difference in the wavelength direction. The multiple sub-wavelength signal lights and the multiple sub-wavelength dummy lights will be incident on different positions of the first optical switch array 40, respectively. The first optical switch array 40 is used to adjust the deflection direction of the incident multiple sub-wavelength signal lights and the multiple sub-wavelength dummy lights. Mirror group 2 is used to guide multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights from the first optical switch array 40 to the second optical switch array 50, so as to convert the positional difference in the port direction into an angular difference in the port direction. Specifically, sub-wavelength signal lights and sub-wavelength dummy lights of the same wavelength have the same incident position on the second optical switch array 50, but different incident angles. The second optical switch array 50 is used to adjust the deflection direction of the incident light at each incident position, so that each wavelength of sub-wavelength signal light or sub-wavelength dummy light is transmitted to the output port 70. This is equivalent to selecting one of the sub-wavelength signal lights and sub-wavelength dummy lights for each wavelength via the second optical switch array 50, wherein the selected sub-wavelength signal light or sub-wavelength dummy light is transmitted to the output port 70. Mirror group 3 is used to converge the sub-wavelength signal lights and / or sub-wavelength dummy lights from the second optical switch array 50 in the Y direction. The second dispersive element 60 is used to combine the sub-wavelength signal lights and / or sub-wavelength dummy lights from mirror group 3. The mirror group 5 is used to shape and collimate the beam after beam combining before guiding it to the output port 70.

[0041] Figure 3(a) is a schematic diagram of the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the first optical switch array. Figure 3(b) is a schematic diagram of the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the second optical switch array. As shown in Figure 3(a), the solid lines represent the spots of sub-wavelength signal light, and the dashed lines represent the spots of sub-wavelength dummy light. The spots of each sub-wavelength signal light and each sub-wavelength dummy light are arranged along the Y direction. Furthermore, on the first optical switch array 40, the spots of sub-wavelength signal light and sub-wavelength dummy light of the same wavelength have positional deviations. As shown in Figure 3(b), on the second optical switch array 50, the spots of sub-wavelength signal light and sub-wavelength dummy light of the same wavelength overlap. It should be understood that in practical applications, the complete overlap or partial overlap of the spots of sub-wavelength signal light and sub-wavelength dummy light of the same wavelength can be considered as the same incident position on the second optical switch array 50.

[0042] It should be noted that both the first optical switch array 40 and the second optical switch array 50 described above are controlled by a controller (not shown in the figure). The controller controls the first optical switch array 40 to achieve wavelength selection, meaning that the first optical switch array 40 can guide a sub-wavelength signal light and / or sub-wavelength dummy light of a specified wavelength to the second optical switch array 50 by adjusting the deflection direction of the incident light. The controller controls the second optical switch array 50 to select between the sub-wavelength signal light and the sub-wavelength dummy light, meaning that the second optical switch array 50 can select one of the two sub-wavelength signal light and sub-wavelength dummy light of the same wavelength by adjusting the deflection direction of the incident light. It should be understood that the first optical switch array 40 has the ability to adjust in any deflection direction, while the second optical switch array 50 can switch only between two deflection directions. Therefore, the second optical switch array 50 has a faster adjustment speed than the first optical switch array 40, enabling rapid uploading of signal light and dummy light. As an example, for sub-wavelength signal light and sub-wavelength dummy light of the same wavelength, if the second optical switch array 50 does not change the deflection direction of the incident light, the sub-wavelength signal light is transmitted to the output port 70; if the second optical switch array 50 changes the deflection direction of the incident light, the sub-wavelength dummy light is transmitted to the output port 70.

[0043] In some possible implementations, if both the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength are incident on the second optical switch array 50, the second optical switch array 50 will select to transmit the sub-wavelength signal light, that is, the sub-wavelength signal light will be transmitted to the output port 70 through the second optical switch array 50. If the sub-wavelength signal light is not incident on the second optical switch array 50 or the energy attenuation of the sub-wavelength signal light is large, the second optical switch array 50 will select to transmit the sub-wavelength dummy light of the same wavelength, that is, the sub-wavelength dummy light will be transmitted to the output port 70 through the second optical switch array 50. As an example, the energy of the sub-wavelength signal light incident on the second optical switch array 50 can be detected by an Optical Performance Monitoring (OPM) device. Assuming that the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the second optical switch array 50 is greater than or equal to a preset value, the second optical switch array 50 will select to upload the first sub-wavelength dummy light with the same wavelength as the first sub-wavelength signal light. Conversely, the second optical switch array 50 will select to upload the first sub-wavelength signal light. The specific preset value is subject to actual application, for example, 5dB, and is not limited here. It should be understood that by detecting the energy of the incident sub-wavelength signal light on the second optical switch array 50, sub-wavelength signal light and sub-wavelength dummy light of the same wavelength can be reasonably selected, so that the normally transmitting sub-wavelength signal light can continue to transmit, and for the abnormally transmitting sub-wavelength signal light, sub-wavelength dummy light can be uploaded to ensure that the light after passing through WSS is in a full-wavelength state.

[0044] It should be noted that this application does not limit the specific types of the first optical switch array 40 and the second optical switch array 50. As an example, the first optical switch array 40 uses Liquid Crystal on Silicon (LCOS), and the second optical switch array 50 uses a Digital Light Processor (DLP). It should be understood that DLP can also be called a Digital Micromirror Device (DMD). This application also does not limit the specific types of the first dispersive element 30 and the second dispersive element 60. As an example, the first dispersive element 30 and the second dispersive element 60 can be gratings, diffractive optical elements (DOE), or metasurface elements, etc.

[0045] In some possible implementations, the WSS shown in Figures 2(a) and 2(b) can also be used to attenuate the sub-wavelength signal light or the sub-wavelength dummy light. It should be understood that attenuation is specifically achieved by adjusting the deflection direction of the sub-wavelength signal light or the sub-wavelength dummy light through the second optical switch array 50. Furthermore, before attenuating the sub-wavelength signal light, it is necessary to prevent sub-wavelength dummy light of the same wavelength from incident on the second optical switch array 50. This is because if both the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength are incident on the second optical switch array 50, attenuation of the sub-wavelength signal light will simultaneously enhance the sub-wavelength dummy light, affecting the attenuation effect on the sub-wavelength signal light. In other words, reducing a portion of the sub-wavelength signal light transmitted to the output port 70 through the second optical switch array 50 will correspondingly increase a portion of the sub-wavelength dummy light transmitted to the output port 70; the two are inversely related. Similarly, before attenuating the sub-wavelength dummy light, it is necessary to prevent sub-wavelength signal light of the same wavelength from incident on the second optical switch array 50. Specific implementation methods are described below.

[0046] Implementation method 1: Attenuate sub-wavelength signal light.

[0047] The first optical switch array 40 adjusts the deflection direction of the incident second sub-wavelength dummy light so that it does not guide the second sub-wavelength dummy light to the second optical switch array 50. The second optical switch array 50 adjusts the deflection direction of the incident second sub-wavelength signal light to attenuate the energy transmitted from the second sub-wavelength signal light to the output port 70. The second sub-wavelength signal light has the same wavelength as the second sub-wavelength dummy light.

[0048] Implementation method 2: Attenuating sub-wavelength pseudo-light.

[0049] The first optical switch array 40 adjusts the deflection direction of the incident third sub-wavelength signal light so that it is not guided to the second optical switch array 50. The second optical switch array 50 adjusts the deflection direction of the third sub-wavelength dummy light to attenuate the energy transmitted by the third sub-wavelength dummy light to the output port 70. The third sub-wavelength signal light and the third sub-wavelength dummy light have the same wavelength.

[0050] It should be noted that this application does not limit the composition of the above-mentioned lens group 1, lens group 2, lens group 3, lens group 4 and lens group 5. A specific implementation method is provided below.

[0051] As shown in Figures 2(a) and 2(b), lens group 1 includes lenses 1, 2, and 3; lens group 2 includes lenses 4, 5, and 6; lens group 3 includes lenses 7 and 8; lens group 4 includes lenses 9 and 10; and lens group 5 includes lenses 11 and 12. Specifically, lens 9 is used to collimate the incident signal light and dummy light, and lens 10 is used to shape the incident signal light and dummy light. Lens 1 is used to converge multiple sub-wavelength signal lights from multiple signal light input ports 10 in the X direction. Taking the three signal light input ports 10 shown in Figure 2(b) as an example, one sub-wavelength signal light transmitted along the optical axis of lens 1 is transmitted through lens 1 to the first optical switch array 40, and the other two sub-wavelength signal lights are refracted through lens 1 to the first optical switch array 40. The three sub-wavelength signal lights are converged to the same position of the first optical switch array 40 in the X direction. Lens 2 functions similarly to lens 1, transmitting or refracting the incident sub-wavelength dummy light in the X direction, so that the incident sub-wavelength dummy light and the sub-wavelength signal light on the first optical switch array 40 have different incident positions in the X direction. Lens 3 is used to collimate the incident multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights in the Y direction. Lens 4 is used to converge the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the Y direction. Lens 5 is used to converge the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the X direction. Lens 6 is used to collimate the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the Y direction. Lens 7 is used to converge the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the Y direction. Lens 8 is used to perform beam shaping on the incident sub-wavelength signal light and the incident sub-wavelength dummy light. Lens 11 is used to perform beam shaping on the light after it has been combined by the second dispersive element 60. Lens 12 is used to collimate the light after it has been combined.

[0052] In one possible implementation, as shown in FIG2(a), the front focal plane of lens 10 coincides with the rear focal plane of lens 9. A first dispersive element 30 is located on the rear focal plane of lens 10 and on the front focal plane of lens 3. A first optical switch array 40 is located on the rear focal plane of lens 3 and on the front focal plane of lens 4. The rear focal plane of lens 4 coincides with the front focal plane of lens 6. A second optical switch array 50 is located on the rear focal plane of lens 6 and on the front focal plane of lens 7. A second dispersive element 60 is located on the rear focal plane of lens 7 and on the front focal plane of lens 11. Lens 11 is located on the front focal plane of lens 12. As shown in FIG2(b), lens 1 is close to the first dispersive element 30, and lens 8 is close to the second dispersive element 60. The front focal plane of lens 1 coincides with the rear focal plane of lens 9. The first optical switch array 40 is located on the rear focal plane of lens 1. The front focal plane of lens 2 coincides with the rear focal plane of lens 9. The first optical switch array 40 is located on the rear focal plane of lens 2. The first optical switch array 40 is located on the front focal plane of lens 5, and the second optical switch array 50 is located on the rear focal plane of lens 5. The second optical switch array 50 is located on the front focal plane of lens 8. The rear focal plane of lens 8 coincides with the front focal plane of lens 12.

[0053] It should be noted that, based on the WSS shown in Figures 2(a) and 2(b), modifications can be made to allow multiple sub-wavelength pseudo-lights from mirror group 1 to be directly transmitted to mirror group 2 without passing through the first optical switch array 40. This will be described below with reference to the accompanying drawings.

[0054] Figure 4(a) is a schematic diagram of the second optical path of the WSS in the dispersion direction in an embodiment of this application. Figure 4(b) is a schematic diagram of the second optical path of the WSS in the port direction in an embodiment of this application. It should be understood that Figure 4(a) shows the schematic diagram of the optical path of the dummy light in the dispersion direction in this embodiment. The schematic diagram of the signal light beam in the dispersion direction in this embodiment is the same as that in Figure 2(a) above. As shown in Figures 4(a) and 4(b), the sub-wavelength signal light passes through the first optical switch array 40, while the sub-wavelength dummy light does not pass through the first optical switch array 40. In this embodiment, the first optical switch array 40 does not need to adjust the deflection direction of the sub-wavelength dummy light, and each sub-wavelength dummy light will be incident on the second optical switch array 50. Therefore, a smaller first optical switch array 40 can be used, reducing costs. However, this embodiment cannot be applied to scenarios where attenuation of the sub-wavelength signal light is required. It should be understood that, apart from the differences described above, this embodiment is similar to the embodiments shown in Figures 2(a) and 2(b). Other identical features can be found in the relevant descriptions of the embodiments shown in Figures 2(a) and 2(b), which will not be repeated here.

[0055] As described in the above embodiments, the incident positions of sub-wavelength signal light and sub-wavelength dummy light of the same wavelength on the second optical switch array are the same. The function of the second optical switch array is to adjust the deflection direction of the incident light at each incident position, thereby selecting one of the sub-wavelength signal light and sub-wavelength dummy light for each wavelength. The selected sub-wavelength signal light or sub-wavelength dummy light can be transmitted to the output port. In this way, even if a certain wavelength of signal light drops during transmission, the second optical switch array can select the dummy light of that wavelength to upload dummy light, filling the channel of the dropped signal light, thus maintaining a full-wavelength state, stabilizing the SRS effect, and improving the stability of signal transmission. In addition, using the second optical switch array only requires switching between two output directions, resulting in faster adjustment speed and enabling rapid uploading of signal light and dummy light.

[0056] The above embodiments illustrate one type of WSS structure provided in this application, which mainly selects the carrier signal light or dummy light by adjusting the deflection direction of the incident light. Another WSS structure provided in this application will be described below, which mainly selects the carrier signal light or dummy light by adjusting the polarization state of the light.

[0057] Figure 5(a) is a schematic diagram of the third optical path of the WSS in the dispersion direction in an embodiment of this application. Figure 5(b) is a schematic diagram of the third optical path of the WSS in the port direction in an embodiment of this application. As shown in Figures 5(a) and 5(b), the wavelength selective switch includes: a signal light input port 10, a dummy light input port 20, a first dispersion element 30, an optical switch array 40, a second dispersion element 60, an output port 70, a first polarization conversion device 80, a second polarization conversion device 90, a polarization combiner 100, a polarization conversion array 110, a polarization separator 120, a mirror group 1, a mirror group 2, and a mirror group 3. The signal light input port 10 and the dummy light input port 20 are distributed in the X direction. Optionally, the wavelength selective switch may further include a mirror group 4 and a mirror group 5.

[0058] Specifically, the signal light from the signal light input port 10 has components in both the first and second polarization states. Similarly, the dummy light from the dummy light input port 20 also has components in both the first and second polarization states. The first and second polarization states are orthogonal to each other. The first polarization conversion device 80 converts the signal light from the signal light input port 10 into the first polarization state. The second polarization conversion device 90 converts the dummy light from the dummy light input port 20 into the second polarization state. The mirror group 4 collimates and shapes the signal light from the signal light input port 10 before guiding it to the first dispersive element 30, and collimates and shapes the dummy light from the dummy light input port 20 before guiding it to the first dispersive element 30. The first dispersive element 30 decomposes the incident signal light into multiple sub-wavelength signal lights in the Y direction and decomposes the incident dummy light into multiple sub-wavelength dummy lights in the Y direction. The wavelengths of the multiple sub-wavelength signal lights and the multiple sub-wavelength dummy lights are all different. Mirror group 1 is used to collimate multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights in the Y direction, converting angular differences in the wavelength direction into positional differences in the wavelength direction. The multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights are incident on different positions of the optical switch array 40. The optical switch array 40 is used to adjust the deflection direction of the incident multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights. Mirror group 2 is used to guide the multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights from the optical switch array 40 to the polarization combiner 100. The polarization combiner 100 is used to combine the input sub-wavelength signal lights and sub-wavelength dummy lights, and then guide the combined sub-wavelength signal lights and sub-wavelength dummy lights to the polarization conversion array 110. Sub-wavelength signal lights and sub-wavelength dummy lights of the same wavelength have the same incident position on the polarization conversion array 110. The polarization conversion array 110 is used to adjust the polarization state of the incident light at each incident position to select the polarization state of each sub-wavelength signal light and each sub-wavelength dummy light output from the polarization conversion array 110. Sub-wavelength signal light and sub-wavelength dummy light of the same wavelength output from the polarization conversion array 110 have different polarization states. The polarization separator 120 is used to transmit the input sub-wavelength signal light and / or sub-wavelength dummy light with a first polarization state and to reflect the input sub-wavelength signal light and / or sub-wavelength dummy light with a second polarization state. The mirror group 3 is used to converge the sub-wavelength signal light and / or sub-wavelength dummy light transmitted by the polarization separator 120 in the Y direction. The second dispersive element 60 is used to combine the sub-wavelength signal light and / or sub-wavelength dummy light from the mirror group 3. The mirror group 5 is used to perform beam shaping and collimation on the combined light before guiding it to the output port 70.

[0059] In this embodiment, the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the optical switch array 40 can be as shown in Figure 3(a) above, and the spot distribution of sub-wavelength signal light and sub-wavelength dummy light on the polarization conversion array 110 can be as shown in Figure 3(b) above. Complete overlap or partial overlap of the spot of sub-wavelength signal light and sub-wavelength dummy light of the same wavelength can be considered as having the same incident position on the polarization conversion array 110.

[0060] It should be noted that both the optical switch array 40 and the polarization conversion array 110 described above are controlled by a controller (not shown in the figure). The controller achieves wavelength selection by controlling the optical switch array 40, that is, the optical switch array 40 can guide a sub-wavelength signal light and / or sub-wavelength dummy light of a specified wavelength to the polarization conversion array 110 by adjusting the deflection direction of the incident light. The controller controls the polarization conversion array 110 to perform polarization state conversion on sub-wavelength signal light and sub-wavelength dummy light of the same wavelength, and combines this with the polarization separator 120 to perform a two-way selection between the sub-wavelength signal light and sub-wavelength dummy light of the same wavelength. It should be understood that the polarization conversion array 110 only needs to perform polarization state conversion on the incident light, resulting in faster adjustment speed and enabling rapid uploading of signal light and dummy light. As an example, for sub-wavelength signal light and sub-wavelength dummy light of the same wavelength, if the polarization conversion array 110 does not change the polarization state of the incident light, the sub-wavelength signal light will be transmitted to the output port 70 through the polarization separator 120; if the polarization conversion array 110 changes the polarization state of the incident light, the sub-wavelength dummy light will be transmitted to the output port 70 through the polarization separator 120.

[0061] In some possible implementations, if both the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength are incident on the polarization conversion array 110, the sub-wavelength signal light output from the polarization conversion array 110 will maintain a first polarization state, meaning the sub-wavelength signal light can be transmitted to the output port 70 through the polarization separator 120. If the sub-wavelength signal light is not incident on the polarization conversion array 110 or the energy attenuation of the sub-wavelength signal light is large, the polarization conversion array 110 will convert the sub-wavelength dummy light of the same wavelength to a first polarization state, meaning the sub-wavelength dummy light can be transmitted to the output port 70 through the polarization separator 120. As an example, the energy of the sub-wavelength signal light incident on the polarization conversion array 110 can be detected using an OPM device. Assuming the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the polarization conversion array 110 is greater than or equal to a preset value, the first sub-wavelength dummy light output by the polarization conversion array 110 has a first polarization state. Conversely, the first sub-wavelength signal light output by the polarization conversion array 110 maintains the first polarization state. The specific preset value is subject to actual application, for example, 5dB, and is not limited here. It should be understood that by detecting the energy of the incident sub-wavelength signal light on the polarization conversion array 110, sub-wavelength signal light and sub-wavelength dummy light of the same wavelength can be reasonably selected, so that the normally transmitted sub-wavelength signal light can continue to transmit, and for the abnormally transmitted sub-wavelength signal light, sub-wavelength dummy light can be uploaded to ensure that the light after passing through WSS is in a full-wavelength state.

[0062] It should be noted that this application does not limit the specific types of the optical switch array 40 and the polarization conversion array 110. As an example, the optical switch array 40 uses LCOS, and the polarization conversion array 110 uses ferroelectric liquid crystal on silicon (F-LCOS). This application also does not limit the specific types of the first dispersion element 30 and the second dispersion element 60. As an example, the first dispersion element 30 and the second dispersion element 60 can be gratings, DOEs, or metasurface elements, etc.

[0063] In some possible implementations, the WSS shown in Figures 5(a) and 5(b) can also be used to attenuate the sub-wavelength signal light or the sub-wavelength dummy light. It should be understood that attenuation is specifically achieved by adjusting the polarization state of the sub-wavelength signal light or the sub-wavelength dummy light through the polarization conversion array 110. Furthermore, before attenuating the sub-wavelength signal light, it is necessary to prevent sub-wavelength dummy light of the same wavelength from incident on the polarization conversion array 110. This is because if both the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength are incident on the polarization conversion array 110, attenuation of the sub-wavelength signal light will simultaneously enhance the sub-wavelength dummy light, affecting the attenuation effect on the sub-wavelength signal light. In other words, reducing a portion of the sub-wavelength signal light transmitted to the output port 70 through the polarization conversion array 110 will correspondingly increase a portion of the sub-wavelength dummy light transmitted to the output port 70; the two are inversely related. Similarly, before attenuating the sub-wavelength dummy light, it is necessary to prevent sub-wavelength signal light of the same wavelength from incident on the polarization conversion array 110. Specific implementation methods are described below.

[0064] Implementation method 1: Attenuate sub-wavelength signal light.

[0065] The optical switch array 40 adjusts the deflection direction of the incident second sub-wavelength dummy light so that it does not guide the second sub-wavelength dummy light to the polarization combiner 100. The polarization conversion array 110 adjusts the polarization state of the incident second sub-wavelength signal light to attenuate the energy transmitted by the second sub-wavelength signal light to the output port 70. The second sub-wavelength signal light has the same wavelength as the second sub-wavelength dummy light.

[0066] Implementation method 2: Attenuating sub-wavelength pseudo-light.

[0067] The optical switch array 40 adjusts the deflection direction of the incident third sub-wavelength signal light so that it does not guide the polarization combiner 100. The polarization conversion array 110 adjusts the deflection direction of the third sub-wavelength dummy light to attenuate the energy transmitted by the third sub-wavelength dummy light to the output port 70. The third sub-wavelength signal light and the third sub-wavelength dummy light have the same wavelength.

[0068] It should be noted that this application does not limit the composition of the above-mentioned lens group 1, lens group 2, lens group 3, lens group 4 and lens group 5. A specific implementation method is provided below.

[0069] As shown in Figures 5(a) and 5(b), mirror group 1 includes lens 1, lens 2, and lens 3; mirror group 2 includes lens 4, lens 5, lens 6, lens 13, and a reflector; mirror group 3 includes lens 7 and lens 8; mirror group 4 includes lens 9 and lens 10; and mirror group 5 includes lens 11 and lens 12. Specifically, lens 9 is used to collimate the incident signal light and dummy light, and lens 10 is used to shape the incident signal light and dummy light. Lens 1 is used to converge multiple sub-wavelength signal lights from multiple signal light input ports 10 in the X direction. Taking the three signal light input ports 10 shown in Figure 5(b) as an example, one sub-wavelength signal light transmitted along the optical axis of lens 1 is transmitted through lens 1 to the optical switch array 40, and the other two sub-wavelength signal lights are refracted through lens 1 to the optical switch array 40. The three sub-wavelength signal lights are converged to the same position of the optical switch array 40 in the X direction. Lens 2 functions similarly to lens 1, transmitting or refracting the incident sub-wavelength dummy light in the X direction, so that the incident sub-wavelength dummy light and the sub-wavelength signal light on the optical switch array 40 have different incident positions in the X direction. Lens 3 is used to collimate the incident multiple sub-wavelength signal lights and multiple sub-wavelength dummy lights in the Y direction. Lens 4 is used to converge the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the Y direction. Lens 5 is used to shape the incident sub-wavelength signal light. Lens 6 is used to collimate the incident sub-wavelength signal light in the Y direction. Lens 13 is used to shape the incident sub-wavelength dummy light, and the reflector is used to reflect the sub-wavelength dummy light from lens 13 to the polarization combiner 100. Lens 7 is used to converge the incident sub-wavelength signal light and the incident sub-wavelength dummy light in the Y direction. Lens 8 is used to shape the incident sub-wavelength signal light and the incident sub-wavelength dummy light. Lens 11 is used to shape the beam of light after it has been combined by the second dispersive element 60, and lens 12 is used to collimate the combined light.

[0070] In one possible implementation, as shown in FIG5(a), the front focal plane of lens 10 coincides with the rear focal plane of lens 9. The first dispersive element 30 is located on the rear focal plane of lens 10 and on the front focal plane of lens 3. The optical switch array 40 is located on the rear focal plane of lens 3 and on the front focal plane of lens 4. The rear focal plane of lens 4 coincides with the front focal plane of lens 6. The polarization conversion array 110 is located on the rear focal plane of lens 6 and on the front focal plane of lens 7. The second dispersive element 60 is located on the rear focal plane of lens 7 and on the front focal plane of lens 11. Lens 11 is located on the front focal plane of lens 12. As shown in FIG5(b), lens 1 is close to the first dispersive element 30, and lens 8 is close to the second dispersive element 60. The front focal plane of lens 1 coincides with the rear focal plane of lens 9. The optical switch array 40 is located on the rear focal plane of lens 1. The front focal plane of lens 2 coincides with the rear focal plane of lens 9. The optical switch array 40 is located on the rear focal plane of lens 2. Optical switch array 40 is located on the front focal plane of lens 5, and polarization conversion array 110 is located on the rear focal plane of lens 5. Optical switch array 40 is located on the front focal plane of lens 13, and polarization conversion array 110 is located on the rear focal plane of lens 13. Polarization conversion array 110 is located on the front focal plane of lens 8. The rear focal plane of lens 8 coincides with the front focal plane of lens 12.

[0071] It should be noted that, based on the WSS shown in Figures 5(a) and 5(b), modifications can be made to allow multiple sub-wavelength pseudo-lights from mirror group 1 to be directly transmitted to mirror group 2 without passing through the optical switch array 40. This will be described below with reference to the accompanying drawings.

[0072] Figure 6(a) is a schematic diagram of the fourth optical path of the WSS in the dispersion direction in an embodiment of this application. Figure 6(b) is a schematic diagram of the fourth optical path of the WSS in the port direction in an embodiment of this application. It should be understood that Figure 6(a) shows the schematic diagram of the optical path of the dummy light in the dispersion direction in this embodiment. The schematic diagram of the signal light beam in the dispersion direction in this embodiment is the same as that in Figure 5(a) above. As shown in Figures 6(a) and 6(b), the sub-wavelength signal light passes through the optical switch array 40, while the sub-wavelength dummy light does not pass through the optical switch array 40. In this embodiment, the optical switch array 40 does not need to adjust the deflection direction of the sub-wavelength dummy light, and each sub-wavelength dummy light will be incident on the polarization combiner 100. Therefore, a smaller optical switch array 40 can be used, reducing costs. However, this embodiment cannot be applied to scenarios where attenuation of the sub-wavelength signal light is required. It should be understood that, apart from the differences described above, this embodiment is similar to the embodiments shown in Figures 5(a) and 5(b). Other identical features can be found in the relevant descriptions of the embodiments shown in Figures 5(a) and 5(b), which will not be repeated here.

[0073] As described in the above embodiments, sub-wavelength signal light and sub-wavelength dummy light of the same wavelength have the same incident position on the polarization conversion array. The function of the polarization conversion array is to adjust the polarization state of the incident light at each incident position, and in conjunction with the polarization separator, to select one of the sub-wavelength signal light and sub-wavelength dummy light for each wavelength. The selected sub-wavelength signal light or sub-wavelength dummy light can be transmitted to the output port. In this way, even if the signal light of a certain wavelength drops during transmission, the polarization conversion array and the polarization separator can select the dummy light of that wavelength to fill the channel of the dropped signal light, thereby maintaining a full-wavelength state, stabilizing the SRS effect, and improving the stability of signal transmission. In addition, using a polarization conversion array only requires switching the incident light between two polarization states, resulting in faster adjustment speed and enabling rapid uploading of signal light and dummy light.

[0074] It should be noted that the embodiments described above are all based on a transmissive optical switch array 40. In some possible implementations, a reflective optical switch array 40 may also be used. That is, the output port 70 in the WSS is located on the same side as the signal light input port 10 and the dummy light input port 20, and a folded optical path is used. It should be understood that the implementation using a reflective optical switch array 40 can be obtained by making simple modifications to the above embodiments, and therefore, no further accompanying drawings or textual descriptions are provided here.

[0075] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A wavelength selective switch (WSS), characterized in that, include: The system includes a signal light input port, a dummy light input port, an output port, a first dispersive element, a second dispersive element, a first optical switch array, a second optical switch array, a first mirror group, a second mirror group, and a third mirror group, wherein the signal light input port and the dummy light input port are distributed along a first direction; The first dispersive element is used to decompose the signal light from the signal light input port into multiple sub-wavelength signal light in the second direction, and to decompose the dummy light from the dummy light input port into multiple sub-wavelength dummy light in the second direction, wherein the second direction is perpendicular to the first direction; The first mirror group is used to collimate the plurality of sub-wavelength signal lights and the plurality of sub-wavelength dummy lights in the second direction; The first optical switch array is used to adjust the deflection direction of multiple sub-wavelength signal light from the first mirror group; The second mirror group is used to guide the sub-wavelength signal light from the first optical switch array and the sub-wavelength dummy light from the first mirror group to the second optical switch array, wherein the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength have the same incident position on the second optical switch array but different incident angles. The second optical switch array is used to adjust the deflection direction of the incident light at each incident position so that the sub-wavelength signal light or sub-wavelength dummy light of each wavelength is transmitted to the output port. The third mirror group is used to converge sub-wavelength signal light and / or sub-wavelength dummy light from the second optical switch array in the second direction; The second dispersive element is used to combine the sub-wavelength signal light and / or sub-wavelength dummy light from the third mirror group and guide the combined light to the output port.

2. The WSS according to claim 1, characterized in that, If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the second optical switch array is greater than or equal to a preset value, then the first sub-wavelength dummy light incident at the first incident position is transmitted to the output port through the second optical switch array. If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the second optical switch array is less than the preset value, then the first sub-wavelength signal light is transmitted to the output port through the second optical switch array.

3. The WSS according to claim 1 or 2, characterized in that, Multiple sub-wavelength pseudo-lights from the first mirror group are transmitted to the second mirror group via the first optical switch array.

4. The WSS according to claim 3, characterized in that, The first optical switch array is also used to adjust the deflection direction of the second sub-wavelength dummy light from the first mirror group, wherein the second sub-wavelength dummy light after the deflection direction is adjusted is not guided to the second optical switch array; The second optical switch array is used to adjust the deflection direction of the second sub-wavelength signal light from the second mirror group to attenuate the energy transmitted by the second sub-wavelength signal light to the output port. The second sub-wavelength dummy light has the same wavelength as the second sub-wavelength signal light.

5. The WSS according to claim 1 or 2, characterized in that, The third sub-wavelength signal light is not guided to the second optical switch array after its deflection direction is adjusted by the first optical switch array. The second optical switch array is used to adjust the deflection direction of the third sub-wavelength dummy light from the second mirror group to attenuate the energy transmitted by the third sub-wavelength dummy light to the output port. The third sub-wavelength dummy light has the same wavelength as the third sub-wavelength signal light.

6. The WSS according to claim 1 or 2, characterized in that, The WSS also includes a fourth lens group and a fifth lens group; The fourth mirror group is used to collimate and shape the signal light from the signal light input port before guiding it to the first dispersive element, and to collimate and shape the dummy light from the dummy light input port before guiding it to the first dispersive element. The fifth mirror group is used to collimate and shape the beam of light from the combined light source of the second dispersive element before guiding it to the output port.

7. The WSS according to claim 1 or 2, characterized in that, The first lens group includes a first lens, a second lens, and a third lens; The first lens is used to transmit the plurality of sub-wavelength signal light from the first dispersive element, or to refract the plurality of sub-wavelength signal light from the first dispersive element in the first direction; The second lens is used to transmit the plurality of sub-wavelength pseudo-light from the first dispersive element, or to refract the plurality of sub-wavelength pseudo-light from the first dispersive element in the first direction; The third lens is used to collimate the plurality of sub-wavelength signal lights from the first lens in the second direction, and to collimate the plurality of sub-wavelength dummy lights from the second lens.

8. The WSS according to claim 1 or 2, characterized in that, The second lens group includes a fourth lens, a fifth lens, and a sixth lens; The fourth lens is used to converge the sub-wavelength signal light from the first optical switch array in the second direction and to converge the sub-wavelength dummy light from the first mirror group. The fifth lens is used to converge the sub-wavelength signal light and sub-wavelength dummy light from the fourth lens in the first direction; The sixth lens is used to collimate and guide the sub-wavelength signal light and sub-wavelength dummy light from the fifth lens in the second direction to the second optical switch array.

9. The WSS according to claim 1 or 2, characterized in that, The third lens group includes a seventh lens and an eighth lens; The seventh lens is used to converge the sub-wavelength signal light from the second optical switch array in the second direction and to converge the sub-wavelength dummy light from the second optical switch array. The eighth lens is used for beam shaping of the sub-wavelength signal light and sub-wavelength dummy light from the seventh lens.

10. The WSS according to claim 1 or 2, characterized in that, The first optical switch array is a liquid crystal on silicon (LCOS), and the second optical switch array is a digital light processor (DLP).

11. The WSS according to claim 1 or 2, characterized in that, The WSS also includes a controller, which controls the first optical switch array and the second optical switch array.

12. A wavelength selective switch (WSS), characterized in that, include: The system includes a signal light input port, a dummy light input port, an output port, a first dispersion element, a second dispersion element, an optical switch array, a first polarization conversion device, a second polarization conversion device, a polarization combiner, a polarization conversion array, a polarization separator, a first mirror group, a second mirror group, and a third mirror group, wherein the signal light input port and the dummy light input port are distributed along a first direction; The first polarization conversion device is used to convert the signal light from the signal light input port into a first polarization state; The second polarization conversion device is used to convert the dummy light from the dummy light input port into a second polarization state, wherein the first polarization state and the second polarization state are orthogonal to each other; The first dispersive element is used to decompose the signal light from the first polarization conversion device into multiple sub-wavelength signal light in the second direction, and to decompose the dummy light from the second polarization conversion device into multiple sub-wavelength dummy light in the second direction, wherein the second direction is perpendicular to the first direction; The first mirror group is used to collimate the plurality of sub-wavelength signal lights and the plurality of sub-wavelength dummy lights in the second direction; The optical switch array is used to adjust the deflection direction of multiple sub-wavelength signal light from the first mirror group; The second mirror group is used to guide the sub-wavelength signal light from the optical switch array and the sub-wavelength dummy light from the first mirror group to the polarization combiner; The polarization beam combiner is used to combine the sub-wavelength signal light and the sub-wavelength dummy light from the second mirror group, and guide the combined sub-wavelength signal light and the sub-wavelength dummy light to the polarization conversion array, wherein the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength have the same incident position on the polarization conversion array; The polarization conversion array is used to adjust the polarization state of the incident light at each incident position to select the polarization state of each sub-wavelength signal light and each sub-wavelength dummy light output from the polarization conversion array, wherein the polarization states of the sub-wavelength signal light and the sub-wavelength dummy light of the same wavelength output from the polarization conversion array are different. The polarization separator is used to transmit sub-wavelength signal light and / or sub-wavelength dummy light with a first polarization state from the polarization conversion array, and to reflect sub-wavelength signal light and / or sub-wavelength dummy light with a second polarization state from the polarization conversion array. The third mirror group is used to converge the sub-wavelength signal light and / or sub-wavelength dummy light transmitted by the polarization separator in the second direction; The second dispersive element is used to combine the sub-wavelength signal light and / or sub-wavelength dummy light from the third mirror group and guide the combined light to the output port.

13. The WSS according to claim 12, characterized in that, If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the polarization conversion array is greater than or equal to a preset value, then the first sub-wavelength dummy light incident at the first incident position has a first polarization state after passing through the polarization conversion array, and the first sub-wavelength signal light has a second polarization state after passing through the polarization conversion array. If the energy attenuation of the first sub-wavelength signal light incident at the first incident position on the polarization conversion array is less than the preset value, then the first sub-wavelength dummy light has a second polarization state after passing through the polarization conversion array, and the first sub-wavelength signal light has a first polarization state after passing through the polarization conversion array.

14. The WSS according to claim 12 or 13, characterized in that, Multiple sub-wavelength pseudo-lights from the first mirror group are transmitted to the second mirror group via the optical switch array.

15. The WSS according to claim 14, characterized in that, The optical switch array is also used to adjust the deflection direction of the second sub-wavelength dummy light from the first mirror group, wherein the second sub-wavelength dummy light after the deflection direction is adjusted is not guided to the polarization beam combiner. The polarization conversion array is used to adjust the polarization state of the second sub-wavelength signal light from the polarization combiner to attenuate the energy transmitted by the second sub-wavelength signal light to the output port. The second sub-wavelength dummy light has the same wavelength as the second sub-wavelength signal light.

16. The WSS according to claim 12 or 13, characterized in that, The third sub-wavelength signal light does not guide the polarization combiner after its deflection direction is adjusted by the optical switch array. The polarization conversion array is used to adjust the polarization state of the third sub-wavelength dummy light from the polarization combiner to attenuate the energy transmitted by the third sub-wavelength dummy light to the output port. The third sub-wavelength dummy light has the same wavelength as the third sub-wavelength signal light.

17. The WSS according to claim 12 or 13, characterized in that, The WSS also includes a fourth lens group and a fifth lens group; The fourth mirror group is used to collimate and shape the signal light from the signal light input port before guiding it to the first polarization conversion device, and to collimate and shape the dummy light from the dummy light input port before guiding it to the first polarization conversion device. The fifth mirror group is used to collimate and shape the beam of light from the combined light source of the second dispersive element before guiding it to the output port.

18. The WSS according to claim 12 or 13, characterized in that, The first lens group includes a first lens, a second lens, and a third lens; The first lens is used to transmit the plurality of sub-wavelength signal light from the first dispersive element, or to refract the plurality of sub-wavelength signal light from the first dispersive element in the first direction; The second lens is used to transmit the plurality of sub-wavelength pseudo-light from the first dispersive element, or to refract the plurality of sub-wavelength pseudo-light from the first dispersive element in the first direction; The third lens is used to collimate the plurality of sub-wavelength signal lights from the first lens in the second direction, and to collimate the plurality of sub-wavelength dummy lights from the second lens.

19. The WSS according to claim 12 or 13, characterized in that, The second mirror group includes a fourth lens, a fifth lens, a sixth lens, a seventh lens, and a reflecting mirror; The fourth lens is used to converge the sub-wavelength signal light from the optical switch array in the second direction and to converge the sub-wavelength dummy light from the first lens group. The fifth lens is used to perform beam shaping on the sub-wavelength signal light from the fourth lens; The sixth lens is used to collimate the sub-wavelength signal light from the fifth lens in the second direction and guide it to the polarization combiner; The seventh lens is used to perform beam shaping on the sub-wavelength pseudo-light from the fourth lens; The reflector is used to reflect sub-wavelength pseudo-light from the seventh lens to the polarization combiner.

20. The WSS according to claim 12 or 13, characterized in that, The third lens group includes an eighth lens and a ninth lens; The eighth lens is used to converge the sub-wavelength signal light from the polarization separator in the second direction, and to converge the sub-wavelength dummy light from the polarization separator. The ninth lens is used for beam shaping of the sub-wavelength signal light and sub-wavelength dummy light from the eighth lens.

21. The WSS according to claim 12 or 13, characterized in that, The optical switch array is a silicon-based liquid crystal LCOS, and the polarization conversion array is a silicon-based ferroelectric liquid crystal F-LCOS.

22. The WSS according to claim 12 or 13, characterized in that, The WSS also includes a controller, which controls the optical switch array and the polarization conversion array.

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