Wavelength selective switch, optical communication device and system, and optical signal transmission method

Abstract

Disclosed are a wavelength selective switch (WSS), an optical communication device and system, and an optical signal transmission method, which belong to the technical field of optical communications. The WSS comprises: a first port group, a dispersive unit and an optical switching engine. The first port group comprises: M first common ports and N first branch ports, wherein the first common ports are separately used for providing a first multi-wavelength optical signal to the dispersive unit; the dispersive unit is used for dividing the first multi-wavelength optical signal into a plurality of first single-wavelength optical signals on the basis of wavelengths, and respectively transmitting the plurality of first single-wavelength optical signals to different positions on the optical switching engine in a dispersion direction; and the optical switching engine is used for transmitting the first single-wavelength optical signals to the dispersive unit, in order to transmit a first single-wavelength optical signal to one first branch port by means of the dispersive unit. When there are at least two first single-wavelength optical signals having the same wavelength among the plurality of first single-wavelength optical signals received by the optical switching engine, the optical switching engine transmits only one of the at least two first single-wavelength optical signals to a first branch port.

Description

Wavelength selective switch, optical communication device, system and optical signal transmission method

[0001] This application claims priority to Chinese patent application No. 202311612735.5 filed on November 27, 2023, entitled “Wavelength selective switch, optical communication equipment, system and optical signal transmission method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical communication technology, and in particular to a wavelength selective switch (WSS), an optical communication device, a system, and an optical signal transmission method. Background Art

[0003] With the development of optical communication technology, optical communication equipment is being used more and more widely. WSS is used in a variety of optical communication equipment, such as reconfigurable optical add-drop multiplexer (ROADM).

[0004] In related technologies, a WSS includes a port group, a dispersion unit, a primary switching engine, and a secondary switching engine. The port group includes multiple common ports and multiple branch ports. After light from different common ports passes through the dispersion unit, it forms independent wavelength groups in different areas of the primary switching engine, with different wavelength groups corresponding to different common ports. The primary switching engine can perform individual deflection processing on each single-wavelength optical signal in each wavelength group, transmitting it to the secondary optical switching engine. Finally, the secondary switching engine controls the output port of each single-wavelength optical signal. This WSS can transmit an optical signal of any wavelength provided by any public port to any branch port.

[0005] However, the WSS needs to include two-stage switching engines, which results in a complex structure and high cost.

[0006] Summary of the Invention

[0007] The present application provides a WSS, an optical communication device, a system, and an optical signal transmission method, which are conducive to simplifying the structure of a WSS with multiple public ports.

[0008] In a first aspect, the present application provides a WSS. The WSS includes a first port group, a dispersion unit, and an optical switching engine. The first port group includes: M first common ports and N first branch ports, where M is an integer greater than 2, and N is an integer greater than 1, and the M first common ports are respectively used to provide a first multi-wavelength optical signal to the dispersion unit. The dispersion unit is used to separate the first multi-wavelength optical signal from the first common port into a plurality of first single-wavelength optical signals according to wavelength, and transmit the plurality of first single-wavelength optical signals to different positions of the optical switching engine in the dispersion direction. The optical switching engine is used to transmit the plurality of first single-wavelength optical signals from the dispersion unit to the dispersion unit, so that at least one of the plurality of first single-wavelength optical signals is transmitted to one of the first branch ports through the dispersion unit. Here, the plurality of first single-wavelength optical signals output from the same first branch port are combined into one channel to obtain a combined optical signal, and the wavelengths of the first single-wavelength optical signals constituting the combined optical signal are different.

[0009] When at least two first single-wavelength optical signals of the same wavelength exist among the multiple first single-wavelength optical signals transmitted by the dispersion unit to the optical switching engine, the optical switching engine transmits any one of the at least two first single-wavelength optical signals of the same wavelength to the first branch port. That is, when first single-wavelength optical signals of the same wavelength exist among the first multi-wavelength optical signals input from different first common ports, the first single-wavelength optical signals of the same wavelength are transmitted to the same position of the optical switching engine, and the optical switching engine only outputs the first single-wavelength optical signal of the first multi-wavelength optical signals input from one first common port from the first branch port.

[0010] The WSS can be implemented with three or more public ports through a primary switching engine, has a simple structure, and is relatively low in manufacturing cost. Furthermore, the WSS with three or more public ports can improve the flexibility of optical communication system networking.

[0011] Optionally, the M first common ports and the N first branch ports are arranged along a first direction, and a distance between any two of the first common ports is greater than a distance between any two of the first branch ports, so as to avoid mirror crosstalk between the first branch ports.

[0012] Optionally, among the M first common ports, the distance between any pair of first common ports is a first distance, except that the distance between any first common port in the pair of first common ports and any first branch port is a second distance, and the first distance and the second distance are not equal. In this way, mirror image crosstalk can be avoided between any first common port other than the pair of first common ports and the first branch port.

[0013] When the M first common ports and the N first branch ports are arranged along the first direction, the M first common ports and the N first branch ports may be arranged in any one of the following manners:

[0014] Mode 1: The N first branch ports are located between two adjacent first common ports;

[0015] Mode 2: There is one first common port among the N first branch ports.

[0016] Both of these two approaches can easily satisfy the required distance relationship between the first common port and the first branch port.

[0017] Optionally, the WSS further includes: a second port group. The second port group includes: M second common ports and N second branch ports. The M second common ports are respectively used to provide a second multi-wavelength optical signal to the dispersion unit. The dispersion unit is also used to split the second multi-wavelength optical signal from the second common port into a plurality of second single-wavelength optical signals according to wavelength, and transmit the plurality of second single-wavelength optical signals to different positions of the optical switching engine in the dispersion direction, respectively. The first single-wavelength optical signal and the second single-wavelength optical signal with the same wavelength are respectively transmitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction. The optical switching engine is also used to transmit the plurality of second single-wavelength optical signals from the dispersion unit to the dispersion unit, so that at least one second single-wavelength optical signal among the plurality of second single-wavelength optical signals is transmitted to one of the second branch ports through the dispersion unit.

[0018] When at least two second single-wavelength optical signals of the same wavelength exist among the multiple second single-wavelength optical signals transmitted by the dispersion unit to the optical switching engine, the optical switching engine transmits any one of the at least two second single-wavelength optical signals of the same wavelength to the branch port. That is, when a second single-wavelength optical signal of the same wavelength exists among the second multi-wavelength optical signals incident from different second common ports, the second single-wavelength optical signals of the same wavelength are transmitted to the same position of the optical switching engine, and the optical switching engine only emits the second single-wavelength optical signal of the second multi-wavelength optical signals incident from one second common port from the second branch port. Furthermore, since the first single-wavelength optical signal and the second single-wavelength optical signal of the same wavelength are respectively transmitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction, the optical switching engine can independently switch the first single-wavelength optical signal and the second single-wavelength optical signal, so that the transmission of the optical signals corresponding to the first port group and the second port group does not interfere with each other, thereby integrating the other two WSSs together to obtain a twin WSS.

[0019] Optionally, the M second common ports, the N second branch ports, the M first common ports, and the N first branch ports are arranged along the first direction, and a distance between any two of the second common ports is greater than a distance between any two of the second branch ports. Arranging the ports in the first port group and the second port group in a row, and with a distance between any two of the second common ports being greater than a distance between any two of the second branch ports, can eliminate mirror image crosstalk between the second branch ports.

[0020] Optionally, the N first branch ports are located between two adjacent first common ports, and the N second branch ports are located between two adjacent first common ports and between two adjacent second common ports. A first common port exists between the N second branch ports and the N first branch ports. This arrangement fully utilizes the space between the first common ports, further reducing the size of the WSS.

[0021] Optionally, the M second common ports are symmetrically arranged with respect to the M first common ports about a reference plane, and the N first branch ports and the N second branch ports are symmetrically arranged with respect to the reference plane, wherein the reference plane is parallel to the dispersion direction and perpendicular to the first direction. This arrangement facilitates simplifying the optical path design of the WSS.

[0022] Optionally, the light-emitting directions of the M first common ports and the N first branch ports are parallel, the light-emitting directions of the M second common ports and the N second branch ports are parallel, and the light-emitting directions of the M first common ports and the light-emitting directions of the M second common ports form an acute angle. Since the light-emitting directions of the M first common ports and the light-emitting directions of the M second common ports form an acute angle, when the first single-wavelength optical signal corresponding to the first common port and the second single-wavelength optical signal corresponding to the second common port have the same wavelength, the light spots of the first single-wavelength optical signal and the second single-wavelength optical signal having the same wavelength on the optical switching engine are arranged in a direction perpendicular to the dispersion direction.

[0023] Optionally, the WSS further includes a polarization conversion unit and a polarization separation unit. The polarization conversion unit is located on the optical path between the first port group and the dispersion unit, and on the optical path between the second port group and the dispersion unit. The polarization conversion unit is configured to convert the first multi-wavelength optical signal provided by the first port group into first linearly polarized light and transmit the first linearly polarized light to the dispersion unit; and to convert the second multi-wavelength optical signal provided by the second port group into second linearly polarized light and transmit the second linearly polarized light to the dispersion unit. The dispersion unit is configured to emit the first linearly polarized light and the second linearly polarized light of the same wavelength to the same position of the polarization separation unit in the dispersion direction. The polarization separation unit is located on the optical path between the dispersion unit and the optical switching engine, and is configured to emit the first linearly polarized light and the second linearly polarized light of the same wavelength emitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction. The polarization direction of the first linearly polarized light is perpendicular to the polarization direction of the second linearly polarized light.

[0024] In a second aspect, an optical communication device is provided, comprising a control circuit and the aforementioned WSS, wherein the control circuit is connected to the WSS. Optionally, the optical communication device may comprise a single board integrating the control circuit and the WSS.

[0025] In a third aspect, an optical communication system is further provided, the optical communication system comprising: a master node, a backup node, and at least one optical transmission link;

[0026] The master node includes a first WSS, and the backup node includes a second WSS, and the first WSS and the second WSS are any of the aforementioned WSSs. Each of the optical transmission links includes at least one node, and the optical transmission link is connected between a branch port of the first WSS and a branch port of the second WSS. The first WSS is configured to output a first optical signal from a first target branch port of the first WSS to the second node when the link between the first node and the second node is not disconnected. The second WSS is configured to output a second optical signal from a second target branch port of the second WSS to the second node when the link between the first node and the second node is disconnected, and both the second optical signal and the first optical signal are configured to carry information sent to the second node.

[0027] In which, the second node is any node in an optical transmission link, the first node is the main node or the transmission node adjacent to the second node in the optical transmission link where the second node is located, the first target branch port is the branch port of the first WSS connected to the optical transmission link where the second node is located, and the second target branch port is the branch port of the second WSS connected to the optical transmission link where the second node is located.

[0028] Optionally, the first wavelength selective switch has a common port for receiving a line-side optical signal of a master node and a common port for receiving a local optical signal of the master node. The second wavelength selective switch has a common port serving as a protection port, a common port for receiving a line-side optical signal of a backup node, and a common port for receiving a local optical signal of the backup node.

[0029] Optionally, the first optical signal and the second optical signal have different wavelengths. When the optical signals currently used by the second WSS do not have an optical signal with the same wavelength as the first optical signal, the first optical signal can be directly transmitted to the protection port of the second WSS. However, when the optical signals currently used by the second WSS do have an optical signal with the same wavelength as the first optical signal, the first optical signal needs to be converted into a second optical signal with a different wavelength from the first optical signal and different from any wavelength of the optical signals currently used by the second WSS, and then the second optical signal needs to be transmitted to the protection port of the second WSS. In this way, the second optical signal can be normally output from the corresponding branch port in the second WSS.

[0030] Optionally, the optical communication system further includes a first protection component, the first protection component being connected to a common port of the first WSS for receiving line-side optical signals from the master node or to an output terminal of a local device of the master node, and the first protection component being further connected to a protection port of the second WSS. The first protection component is configured to obtain the first optical signal from the common port of the first WSS for receiving line-side optical signals from the master node or to obtain the first optical signal from a local optical signal of the master node, and to input the second optical signal into the protection port of the second WSS.

[0031] Optionally, the first protection component may adopt any one of the following two structures:

[0032] In the first embodiment, the first protection component includes an optical splitter. The input end of the optical splitter is connected to the output end of the local device of the master node. One output end of the optical splitter is connected to the common port of the first WSS for receiving the local optical signal of the master node. The other output end of the optical splitter is connected to the protection port of the second WSS. Using an optical splitter as the first protection component is simple in structure and easy to implement.

[0033] The second type, wherein the first protection component includes a first combiner, a second combiner, and multiple optical switches, wherein the input end of the optical switch is connected to the wavelength conversion unit in the local device of the master node, one output end of the optical switch is connected to the input end of the first combiner, the output end of the first combiner is connected to the common port of the first WSS for receiving the local optical signal of the master node, the other output end of the optical switch is connected to the input end of the second combiner, and the output end of the second combiner is connected to the protection port of the second WSS. The first combiner can be a combiner in the local device of the master node.

[0034] Optionally, the master node further includes a third WSS, the backup node further includes a fourth WSS, and the optical transmission link is further connected between a branch port of the third WSS and a branch port of the fourth WSS. The third WSS is configured to receive a third optical signal from the second node from a third target branch port of the third WSS when the link between the first node and the second node is not disconnected; and the fourth WSS is configured to receive a fourth optical signal from the second node from a fourth target branch port of the fourth WSS when the link between the first node and the second node is disconnected. The third target branch port is a branch port of the third WSS connected to the optical transmission link where the second node is located, and the fourth target branch port is a branch port of the fourth WSS connected to the optical transmission link where the second node is located.

[0035] In some examples, the first WSS and the third WSS are integrated together, and the second WSS and the fourth WSS are integrated together.

[0036] Optionally, the optical communication system further includes a second protection component, connected to a common port of the second WSS for receiving line-side optical signals from the standby node or to an output terminal of a local device of the standby node, and further connected to a protection port of the first WSS. The second protection component is configured to obtain the first optical signal from the common port of the second WSS for receiving line-side optical signals from the standby node or from a local optical signal of the standby node, and to input the second optical signal into the protection port of the first WSS.

[0037] In a fourth aspect, a method for transmitting an optical signal is provided, which is implemented based on any of the optical communication systems provided in the third aspect. The method includes controlling the first WSS to output the first optical signal from a first target branch port of the first WSS to the second node when the link between the first node and the second node is not disconnected; or controlling the second WSS to output the second optical signal from a second target branch port of the second WSS to the second node when the link between the first node and the second node is disconnected.

[0038] The effects of the second to fourth aspects above can refer to the corresponding effects of the first aspect, and this application will not elaborate on them here. In addition, in the third and fourth aspects, when the second node cannot obtain the corresponding optical signal from the master node, since the backup node has three first public ports, the optical signal corresponding to the second node can be input from one of the first public ports of the backup node, and then the optical signal is sent from the backup node to the second node, thereby protecting the optical transmission link. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a light path diagram of a WSS in a port direction x provided by an embodiment of the present application;

[0040] FIG2 is a schematic diagram of the spot distribution of multiple first single-wavelength optical signals on an optical switching engine provided by an embodiment of the present application;

[0041] FIG3 is a light path diagram of another WSS in the port direction x provided by an embodiment of the present application;

[0042] FIG4 is a light path diagram of the WSS in FIG3 in the dispersion direction y;

[0043] 5 is a schematic diagram of the distribution of light spots of a plurality of first single-wavelength optical signals and a plurality of second single-wavelength optical signals on an optical switching engine according to an embodiment of the present application;

[0044] FIG6 is a light path diagram of another WSS in the port direction x provided in an embodiment of the present application;

[0045] FIG7 is a light path diagram of the WSS in FIG6 in the dispersion direction y;

[0046] FIG8 is a light path diagram of another WSS in the port direction x provided in an embodiment of the present application;

[0047] FIG9 is a schematic structural diagram of an optical communication device provided in an embodiment of the present application;

[0048] FIG10 is a schematic structural diagram of an optical communication system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0050] The present invention provides a simple structure of a WSS with multiple common ports. The WSS can use a primary optical switching engine to switch an optical signal of any wavelength in any common port to any branch port. The structure of the WSS will be further described below with reference to FIG1 .

[0051] Figure 1 is an optical path diagram of a WSS in the port direction x provided by an embodiment of the present application. The orthographic projection of the transmission path of the optical signal between the ports of the WSS on the reference plane xz is also the optical path diagram shown in Figure 1. Among them, the orthographic projections of the multiple ports of the WSS in the reference plane xz can be arranged in sequence along the port direction x. The arrangement direction of the multiple ports can be the port direction x, or it can be different from the port direction x, and this application does not limit this. The reference plane xz is perpendicular to the dispersion direction y, and the dispersion direction y will be further introduced in the subsequent content. The orthographic projection of the transmission path on the reference plane xz refers to: when light perpendicular to the reference plane xz is irradiated from the side of the transmission path away from the reference plane xz to the reference plane xz, the projection of the transmission path on the reference plane xz is formed.

[0052] Figure 1 illustrates a WSS with three common ports and four branch ports. As shown in Figure 1, the WSS includes three first common ports COM11 to COM13, four first branch ports P11 to P14, a dispersion unit, and an optical switching engine. The three first common ports COM11 to COM13 and the four first branch ports P11 to P14 constitute a first port group. It should be noted that the number of first common ports and the number of first branch ports in the first port group can be set as needed and are not limited in this embodiment of the present application.

[0053] After the first multi-wavelength optical signal input from any first common port is transmitted to the dispersion unit, it is dispersed by the dispersion unit in the dispersion direction y (perpendicular to the port direction x and direction z in Figure 1) into multiple first single-wavelength optical signals. Then, these first single-wavelength optical signals are transmitted to different positions of the optical switching engine in the dispersion direction y.

[0054] Optionally, the wavelengths of the first single-wavelength optical signals corresponding to the first multi-wavelength optical signals input by different first common ports may be entirely the same, partially the same, or completely different.

[0055] FIG2 is a schematic diagram of the light spot distribution of multiple first single-wavelength optical signals on the optical switching engine provided by an embodiment of the present application. As shown in FIG2 , different ellipses represent the light spots formed by different first single-wavelength optical signals on the optical switching engine. It can be seen that the first single-wavelength optical signals of different wavelengths are transmitted to different positions of the optical switching engine, and these first single-wavelength optical signals are transmitted to multiple positions of the optical switching engine and are arranged in sequence along the dispersion direction y. It should be noted that FIG2 shows 11 first single-wavelength optical signals with wavelengths of λ1 to λ11, but the embodiment of the present application does not limit the number of wavelengths supported by the WSS, and can be set according to actual needs, for example, more than 11 or less than 11.

[0056] Since FIG. 1 shows a view of the xz plane, FIG. 1 only shows a position where a first multi-wavelength optical signal is transmitted to the optical switching engine.

[0057] The optical switching engine can control the output angle of each first single-wavelength optical signal on the optical switching engine based on the first branch port to which the first single-wavelength optical signal is to be transmitted, so that after the first single-wavelength optical signal is emitted from the optical switching engine, it is transmitted through the dispersion unit to the first branch port to which the first single-wavelength optical signal is to be transmitted. In other words, the optical switching engine achieves port-direction displacement of the first single-wavelength optical signal by controlling the output angle of the first single-wavelength optical signal on the optical switching engine.

[0058] As shown in Figure 1, assuming that the multiple first multi-wavelength optical signals include three first single-wavelength optical signals with wavelengths λ1, λ2, and λ3, respectively, the first single-wavelength optical signal with wavelength λ1 is used to be transmitted to the first branch port P11, the first single-wavelength optical signal with wavelength λ2 is used to be transmitted to the first branch port P12, and the first single-wavelength optical signal with wavelength λ3 is used to be transmitted to the first branch port P13. By controlling the output angles of these first single-wavelength optical signals on the optical switching engine, these first single-wavelength optical signals can be transmitted to the branch ports to which they are required to be transmitted.

[0059] It should be noted that in Figure 1, first single-wavelength optical signals of different wavelengths are emitted from a single first branch port, and each first branch port emits a first single-wavelength optical signal of a single wavelength. In actual applications, multiple first single-wavelength optical signals of different wavelengths can also be emitted from the same first branch port, that is, one or more first branch ports may emit first single-wavelength signals of multiple wavelengths.

[0060] The optical switching engine can be a device such as liquid crystal on silicon (LCOS) or a micro-electro-mechanical system (MEMS) capable of controlling the output angle of incident light. For any first single-wavelength optical signal, the optical switching engine can be loaded with a grating and diffract the first single-wavelength optical signal through the grating to control the output angle of the first single-wavelength optical signal.

[0061] The periodic direction of the grating loaded on the optical switching engine is the port direction x. The grating controls the output angle of the first single-wavelength optical signal on the optical switching engine in accordance with the grating equation Λsinθ=λ, where Λ represents the period of the grating, sin represents a sine function, θ represents the deflection angle of the output angle of the first single-wavelength optical signal on the optical switching engine relative to the reflection angle, and λ represents the wavelength of the first single-wavelength optical signal.

[0062] From the above grating equation, it can be seen that for two first single-wavelength optical signals (with different wavelengths) transmitted from the same first common port to two locations in the dispersion direction of the optical switching engine, if these two first single-wavelength optical signals need to be transmitted to the same first branch port, then the optical switching engine needs to load gratings of different periods at these two locations so that the deflection angles of the exit angles of the two first single-wavelength optical signals on the optical switching engine relative to the reflection angle are the same. Since the incident angles of the two first single-wavelength optical signals are the same, the corresponding reflection angles are also the same. Therefore, if the deflection angles are the same, the optical switching engine will emit the two first single-wavelength optical signals in the same exit direction, allowing them to be transmitted to the same first branch port.

[0063] For two first single-wavelength optical signals (with different wavelengths) transmitted from different first common ports to two locations in the dispersion direction of the optical switching engine, if these two first single-wavelength optical signals need to be transmitted to the same first branch port, the optical switching engine needs to load gratings of corresponding periods at these two locations to control the deflection angle of the output angle of the two first single-wavelength optical signals on the optical switching engine relative to the reflection angle. Because the incident angles of the two first single-wavelength optical signals are different, the corresponding reflection angles are also different. Therefore, the deflection angles corresponding to the two first single-wavelength optical signals may be the same or different, depending on the position of the first branch port outputting the two first single-wavelength optical signals in the port direction x.

[0064] As can be seen, the optical switching engine can transmit multiple first single-wavelength optical signals from the dispersion unit to the dispersion unit, so that at least one of the multiple first single-wavelength optical signals is transmitted to a corresponding first branch port through the dispersion unit. The multiple first single-wavelength optical signals output from the same first branch port are combined into a combined optical signal, and the first single-wavelength optical signals that constitute the combined optical signal have different wavelengths.

[0065] When first single-wavelength optical signals of the first wavelength are obtained by dispersing the first multi-wavelength optical signals incident on two first common ports through the dispersion unit and both contain first single-wavelength optical signals of the first wavelength, two first single-wavelength optical signals of the same wavelength will be incident on the same position of the optical switching engine at different incident angles. Because the incident angles of these two first single-wavelength optical signals of the first wavelength are different, the corresponding reflection angles are also different. Therefore, when the deflection angles are the same, the optical switching engine will emit the two first single-wavelength optical signals of the first wavelength at different output directions, so that when the two first single-wavelength optical signals of the first wavelength arrive at the port position, they are at different positions in the port direction x. Therefore, when first single-wavelength optical signals of the first wavelength are incident on different first common ports, the optical switching engine can only emit the first single-wavelength optical signal of the first multi-wavelength optical signals incident on one first common port from the target branch port. Here, the target branch port is one of the multiple first branch ports.

[0066] Because the angular relationship between the incident directions of the two first-wavelength, first-single-wavelength optical signals corresponding to the two first common ports on the optical switching engine is fixed, the angular relationship between the exit directions of the two first-wavelength, first-single-wavelength optical signals emitted by the optical switching engine is also fixed. When the two first-wavelength, first-single-wavelength optical signals return to the port positions, the distance between the exit positions of the two first-wavelength, first-single-wavelength optical signals is equal to the distance between the two first common ports. Therefore, if the distance between the two first common ports is equal to the distance between the two first branch ports, then it is possible that two first-wavelength, first-single-wavelength optical signals will each exit from one first branch port. This situation is called mirror crosstalk.

[0067] For example, for the WSS shown in Figure 1, assume that the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM11 are λ1, λ2, and λ3, and the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM13 are λ1 and λ4. The wavelengths of the five first single-wavelength optical signals emitted from the dispersion unit to the optical switching engine are λ1, λ1, λ2, λ3, and λ4, respectively. If the distance between the first common port COM11 and the first common port COM13 is equal to the distance between the first branch port P11 and the first branch port P12, then when the first single-wavelength optical signal with wavelength λ1 from the first common port COM11 is emitted from the first branch port P11, the first single-wavelength optical signal with wavelength λ1 from the first common port COM13 will be emitted from the first branch port P12.

[0068] In order to avoid the phenomenon of mirror crosstalk, the arrangement positions of the various ports in the first port group can be designed so that when there are at least two first single-wavelength optical signals with the same wavelength among the multiple first single-wavelength optical signals transmitted by the dispersion unit to the optical switching engine, the optical switching engine only transmits one of the at least two first single-wavelength optical signals with the same wavelength to the first branch port.

[0069] For example, the M first common ports and the N first branch ports can be arranged along a first direction (i.e., port direction x), and the distance between any two first common ports is greater than the distance between any two first branch ports. In this way, for two first single-wavelength optical signals of the same wavelength from the two first common ports, when one of the first single-wavelength optical signals is output to the desired first branch port, the other first single-wavelength optical signal will be deflected outside the receiving range of the N first branch ports, thereby ensuring that only one of the at least two first single-wavelength optical signals of the same wavelength emitted by the optical switching engine is transmitted to the first branch port.

[0070] Still using Figure 1 as an example, assume that the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM11 are λ1, λ2, and λ3, and the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM13 are λ1 and λ4. The wavelengths of the five first single-wavelength optical signals emitted by the dispersion unit to the optical switching engine are λ1, λ1, λ2, λ3, and λ4, respectively. Because the distance between the first common port COM11 and the first common port COM13 is greater than the distance between any two first branch ports among the first branch ports P11 to P14, when the first single-wavelength optical signal with wavelength λ1 from the first common port COM11 is emitted from the first branch port P11, the first single-wavelength optical signal with wavelength λ1 from the first common port COM13 will be emitted from a location below the first branch port P14. Since this location is outside the receiving range of the first branch ports P11 to P14, mirror crosstalk will not occur.

[0071] Under the premise that the distance between any two first common ports is greater than the distance between any two first branch ports, the arrangement of the M first common ports and the N first branch ports can be set as needed. Optionally, the arrangement of the M first common ports and the N first branch ports includes but is not limited to the following two.

[0072] The first arrangement: N first branch ports are located between two adjacent first common ports. For example, as shown in Figure 2, four first branch ports P11 to P14 are sequentially arranged between the first common port COM11 and the first common port COM12. In this arrangement, the distance between two first common ports on either side of the N first branch ports must be greater than the distance between any two first branch ports. This arrangement avoids mirror image crosstalk between the first branch ports by simply ensuring that the distance between adjacent first common ports is greater than the distance between the two farthest first branch ports, making it easy to implement.

[0073] The second arrangement: N first branch ports are located on both sides of a first branch port, that is, the N first branch ports are divided into two parts, and a first common port exists between the two parts of the first port. For example, referring to Figure 2 again, the first branch ports P11 to P12 can be arranged in sequence between the first common port COM11 and the first common port COM12, and the first branch ports P13 to P14 can be arranged in sequence between the first common port COM11 and the first common port COM13.

[0074] Continuing with Figure 1 as an example, assume that the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM11 are λ1, λ2, and λ3, and the wavelengths corresponding to the first multi-wavelength optical signal incident on the first common port COM13 are λ1 and λ4. The wavelengths of the five first single-wavelength optical signals emitted by the dispersion unit to the optical switching engine are λ1, λ1, λ2, λ3, and λ4, respectively. If the distance between the first common port COM11 and the first common port COM13 is equal to the distance between the first branch port P11 and the first common port COM12, when the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM13 is emitted from the first branch port P11, the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM11 will be emitted from the first common port P12. In this case, the problem of mirror crosstalk will also exist.

[0075] Therefore, the M first common ports and the N first branch ports may also satisfy the following condition: assuming that the distance between any pair of first common ports is a first distance, the distance from any first common port other than the pair of first common ports to any first branch port is a second distance, and the first distance is not equal to the second distance. Here, any pair of first common ports refers to any two first common ports among the M first common ports.

[0076] Continuing with Figure 1 as an example, if the distance between the first common port COM11 and the first common port COM13 (the first distance) is not equal to the distance between the first common port COM12 and any one of the first branch ports (the second distance), when the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM13 is emitted from the first branch port P11, the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM11 will not be emitted from the first common port P12. Therefore, the mirror image crosstalk problem can be avoided.

[0077] When the distance between any two first common ports is greater than the distance between any two first branch ports, and the first distance is not equal to the second distance are simultaneously satisfied, mirror image crosstalk can be better avoided.

[0078] For example, in Figure 1, the N first branch ports are located between the first common port COM11 and the first common port COM12. The distance between any two first common ports is greater than the distance between any two first branch ports, and the distance between the first common port COM11 and the first common port COM13 is greater than the distance between the first common port COM12 and the first branch port P11. This arrangement can simultaneously meet the requirements that the distance between any two first common ports is greater than the distance between any two first branch ports, and that the first distance is not equal to the second distance.

[0079] It should be noted that if an anti-reflection device is provided on the optical path corresponding to each first common port, then even if the first single-wavelength optical signal is emitted from other first common ports, it will not affect the transmission quality of the optical signal. In this case, it is not necessary to use the above method to avoid the mirror image crosstalk problem of the common port.

[0080] For example, in Figure 1 , the light-emitting directions of the first common ports COM11-COM13 are parallel to the principal optical axis of the dispersion unit, and the light-receiving directions of the first branch ports P11-P14 are also parallel to the principal optical axis of the dispersion unit. In other embodiments, the light-emitting directions of the first common ports COM11-COM13 may intersect with the principal optical axis of the dispersion unit.

[0081] Optionally, the dispersion unit includes an optical element such as a grating, a diffractive optical element (DOE) or a metasurface element, which can separate the received multi-wavelength optical signal into multiple single-wavelength optical signals according to wavelength.

[0082] Optionally, the WSS further includes a first lens group and a second lens group. The first lens group is located in the optical path between the first port group and the dispersion element, and the second lens group is located in the optical path between the dispersion element and the optical switching engine. The first lens group is configured to beam shape the first multi-wavelength optical signal and then direct it to the dispersion element. The second lens group is configured to converge the first single-wavelength optical signal output by the dispersion element in the dispersion direction y, so that the first single-wavelength optical signal forms a light spot on the optical switching engine.

[0083] Illustratively, the first lens group and the second lens group include one or more lenses, which is not limited in the embodiments of the present application.

[0084] In some examples, the first lens group includes a first lens, the dispersive element is located at a back focal plane of the first lens, the second lens group includes a second lens, the dispersive element is located at a front focal plane of the second lens, and the optical switching engine is located at a back focal plane of the second lens.

[0085] Optionally, each port includes an optical fiber and a collimator, and the collimator is located on the optical path between one end of the optical fiber and the first lens group, and is used to collimate the light emitted from the optical fiber, or collimate the light from the dispersion unit before emitting from the optical fiber.

[0086] In summary, the WSS can be implemented with three or more public ports through a primary switching engine, has a simple structure, and is relatively low in manufacturing cost. Furthermore, the WSS with three or more public ports can improve the flexibility of optical communication system networking.

[0087] Figures 1 and 2 illustrate a WSS with one port group. In other embodiments, a WSS may have multiple port groups. The following illustrates a WSS with two port groups. A WSS that integrates two port groups may be referred to as a twin WSS.

[0088] Figure 3 is a light path diagram of a WSS in the port direction x provided by an embodiment of the present application, and Figure 4 is a light path diagram of a WSS in the dispersion direction y provided by an embodiment of the present application. The light path diagram of the WSS in the port direction x is: a view of the light path of the WSS in the dispersion direction y, and the light path diagram of the WSS in the dispersion direction y is: a view of the light path in the WSS in the port direction x. The orthographic projection of the transmission path of the optical signal between the ports of the WSS on the reference plane xz is also the light path diagram of the WSS in the port direction x. The orthographic projection of the transmission path of the optical signal between the ports of the WSS on the plane yz is also the light path diagram of the WSS in the dispersion direction y.

[0089] With reference to Figures 3 and 4, the WSS provided in the embodiments of the present application includes: a first port group, a second port group, a dispersion unit, and an optical switching engine. The first port group includes three first common ports COM11 to COM13 and four first branch ports P11 to P14. The second port group includes three second common ports COM21 to COM23 and four second branch ports P21 to P24.

[0090] The process of the dispersion unit and the optical switching engine processing the first multi-wavelength optical signal from the first common port is shown in FIG1 , and detailed description is omitted here.

[0091] The dispersion unit is further configured to separate the second multi-wavelength optical signal from the second port group into a plurality of second single-wavelength optical signals according to wavelength, and transmit the plurality of second single-wavelength optical signals to different locations of the optical switching engine in the dispersion direction. The optical switching engine is further configured to transmit the second single-wavelength optical signal from the dispersion unit to the dispersion unit, so that the second single-wavelength optical signal is transmitted to a second branch port. When at least two second single-wavelength optical signals of the same wavelength exist among the multiple second single-wavelength optical signals transmitted to the optical switching engine by the dispersion unit, the optical switching engine transmits only one of the at least two second single-wavelength optical signals of the same wavelength to the second branch port. That is, when second single-wavelength optical signals of the same wavelength exist among the second multi-wavelength optical signals input from different second common ports, the second single-wavelength optical signals of the same wavelength are transmitted to the same location of the optical switching engine, and the optical switching engine only outputs the second single-wavelength optical signal from the second multi-wavelength optical signals input from one second common port through the second branch port. The control method for the output port of the second single-wavelength optical signal by the optical switching engine can be referred to as the control method for the output port of the first single-wavelength optical signal, and will not be described in detail here.

[0092] Furthermore, the first single-wavelength optical signal and the second single-wavelength optical signal with the same wavelength are respectively transmitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction.

[0093] FIG5 is a schematic diagram of the light spot distribution of multiple first single-wavelength optical signals and multiple second single-wavelength optical signals on an optical switching engine provided by an embodiment of the present application. As shown in FIG5 , the light spots formed by multiple first single-wavelength optical signals (with wavelengths of λ1 to λ11) on the optical switching engine are arranged in sequence in the dispersion direction y, and the light spots formed by multiple second single-wavelength optical signals (with wavelengths of λ1 to λ11) on the optical switching engine are arranged in sequence in the dispersion direction y. The light spots formed by the first single-wavelength optical signal and the second single-wavelength optical signal of the same wavelength on the optical switching engine are arranged in sequence in a direction perpendicular to the dispersion direction y. For example, in FIG5 , the first single-wavelength optical signal and the second single-wavelength optical signal with a wavelength of λ1 are arranged in sequence in the port direction x. In this way, the optical switching engine is divided into at least a first area and a second area, and the arrangement direction of the first area and the second area is perpendicular to the dispersion direction y. The light spots corresponding to the multiple first single-wavelength optical signals are arranged in a row in the first area, and the light spots corresponding to the multiple second single-wavelength optical signals are arranged in a row in the second area.

[0094] Because the first and second single-wavelength optical signals of the same wavelength are transmitted to different locations of the optical switching engine perpendicular to the dispersion direction y, the optical switching engine processes the first and second single-wavelength optical signals independently. This allows the first and second port groups to share components such as the dispersion unit and the optical switching engine, resulting in a simple and compact twin WSS.

[0095] In an embodiment of the present application, the M second common ports, the N second branch ports, the M first common ports, and the N first branch ports are arranged along a first direction, and the distance between any two second common ports is greater than the distance between any two second branch ports. Thus, for two second single-wavelength optical signals of the same wavelength from two second common ports, when one of the second single-wavelength optical signals is output to the desired first branch port, the other second single-wavelength optical signal will be deflected outside the receiving range of the N second branch ports, thereby ensuring that only one of the at least two second single-wavelength optical signals of the same wavelength emitted by the optical switching engine is transmitted to the second branch port.

[0096] Optionally, the M second common ports and the N second branch ports may further satisfy the following condition: assuming that the distance between any pair of second common ports is a third distance, the distance from any second common port other than the pair of second common ports to any second branch port is a fourth distance, and the third distance is not equal to the fourth distance. Here, any pair of second common ports refers to any two second common ports among the M second common ports. This further prevents mirror crosstalk.

[0097] For example, N first branch ports are located between two adjacent first common ports, and N second branch ports are located between two other adjacent first common ports and between two adjacent second common ports. There is a first common port between the N second branch ports and the N first branch ports. To ensure that the spacing between any two adjacent first common ports is greater than the distance between any two adjacent first branch ports, the spacing between two adjacent first common ports is relatively large. Alternating the ports in the first port group and the ports in the second port group can effectively utilize space and help reduce the size of the WSS.

[0098] For example, as shown in Figure 3, the first branch ports P11-P14 are located between the first common port COM12 and the first common port COM13, the second branch ports P21-P24 are located between the first common port COM11 and the first common port COM13, and the first common port COM11 is located between the first branch ports P11-P14 and the second branch ports P21-P24. Correspondingly, the second branch ports P21-P24 are located between the second common port COM21 and the second common port COM22, the first branch ports P11-P14 are located between the second common port COM21 and the second common port COM23, and the second common port COM21 is located between the first branch ports P11-P14 and the second branch ports P21-P24.

[0099] Optionally, the M second common ports and the M first common ports are arranged symmetrically about a reference plane, the N first branch ports and the N second branch ports are arranged symmetrically about the reference plane, and the reference plane is parallel to the dispersion direction y and perpendicular to the first direction.

[0100] In some examples, the reference plane passes through the principal optical axis of the dispersion unit. In other examples, the reference plane may not pass through the principal optical axis of the dispersion unit, but may be parallel to the principal optical axis of the dispersion unit.

[0101] To achieve the light spot distribution shown in Figure 5, in this embodiment, the light-emitting directions of the M first common ports and the light-receiving directions of the N first branch ports are parallel, the light-emitting directions of the M second common ports and the light-receiving directions of the N second branch ports are parallel, and the angle α (see Figure 3) between the light-emitting directions of the first common ports and the second common ports is an acute angle. By controlling the light-emitting directions of the first and second common ports, the light spot positions of the first and second single-wavelength optical signals on the optical switching engine can be controlled.

[0102] Optionally, the WSS further includes a first lens group and a second lens group. The first lens group is located on the optical path between the first port group and the dispersion unit, and on the optical path between the second port group and the dispersion unit. The second lens group is located on the optical path between the dispersion element and the optical switching engine. The first lens group is used to perform beam shaping on the first multi-wavelength optical signal and the second multi-wavelength optical signal, and then guide them to the dispersion unit. The second lens group is used to converge the first single-wavelength optical signal output by the dispersion unit in the dispersion direction y, so that the first single-wavelength optical signal can form a light spot on the optical switching engine, and to converge the second single-wavelength optical signal output by the dispersion unit in the dispersion direction y, so that the second single-wavelength optical signal can form a light spot on the optical switching engine.

[0103] The implementation of the first lens group, the second lens group, the dispersion unit and the optical switching engine can be found in the relevant description in FIG1 , and a detailed description is omitted here.

[0104] In the embodiments of the present application, the specific value of α can be determined based on the structural parameters of the lens in the switching direction (i.e., the port direction x). The lens in this switching direction can convert differences in incident angles into differences in positions perpendicular to the dispersion direction y of the optical switching engine. This is sufficient as long as the arrangement direction of the light spot positions of the first single-wavelength optical signal and the second single-wavelength optical signal of the same wavelength on the optical switching engine is perpendicular to the dispersion direction y.

[0105] Exemplarily, when the M second common ports are arranged symmetrically with respect to the reference plane, the light emitting directions of the first common ports and the second common ports that are symmetrical with respect to the reference plane are also symmetrical with respect to the reference plane.

[0106] The embodiments shown in Figures 3 and 4 control the light output directions of the first and second common ports, so that the single-wavelength optical signals corresponding to the first and second common ports form light spots in different areas of the optical switching engine. In other embodiments, the polarization state of light can also be used to cause the single-wavelength optical signals corresponding to the first and second common ports to form light spots in different areas of the optical switching engine. This approach is described below with reference to Figures 6 and 7.

[0107] Figure 6 is a light path diagram of another WSS in the port direction provided by an embodiment of the present application. Figure 7 is a light path diagram of the WSS in Figure 6 in the dispersion direction y. As shown in Figures 6 and 7, the WSS includes a first port group, a second port group, a polarization conversion unit, a dispersion unit, a polarization separation unit, and an optical switching engine.

[0108] The arrangement order of the ports in the first port group and the second port group is the same as that of the embodiments shown in Figures 3 and 4 and will not be described in detail here. The polarization conversion unit is located on the optical path between the first port group and the dispersion unit, and on the optical path between the second port group and the dispersion unit. The polarization conversion unit is used to convert the first multi-wavelength optical signal provided by the first port group into multi-wavelength first linearly polarized light and transmit the multi-wavelength first linearly polarized light to the dispersion unit; and to convert the second multi-wavelength optical signal provided by the second port group into multi-wavelength second linearly polarized light and transmit the multi-wavelength second linearly polarized light to the dispersion unit. The polarization direction of the first linearly polarized light is perpendicular to the polarization direction of the second linearly polarized light.

[0109] The dispersion unit is used to separate the multi-wavelength first linear polarized light into a plurality of single-wavelength first linear polarized lights according to their wavelengths, and transmit the plurality of single-wavelength first linear polarized lights to different positions of the optical switching engine in the dispersion direction; to separate the multi-wavelength second linear polarized light into a plurality of single-wavelength second linear polarized lights according to their wavelengths, and transmit the plurality of single-wavelength second linear polarized lights to different positions of the optical switching engine in the dispersion direction y, wherein the single-wavelength first linear polarized light and the single-wavelength second linear polarized light of the same wavelength are transmitted to the same position of the polarization separation unit in the dispersion direction y. The distribution diagram of the light spots formed by the single-wavelength first linear polarized light and the single-wavelength second linear polarized light on the optical switching engine is the same as that in FIG5 , except that the first single-wavelength optical signal in FIG5 is replaced by the single-wavelength first linear polarized light, and the second single-wavelength optical signal in FIG5 is replaced by the single-wavelength second linear polarized light.

[0110] The polarization separation unit is located on the optical path between the dispersion unit and the optical switching engine. The polarization separation unit is used to direct the first linear polarized light of a single wavelength and the second linear polarized light of a single wavelength of the same wavelength emitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction y.

[0111] The optical switching engine is used to control the emission direction of the received single wavelength first polarized light and second linear polarized light of each wavelength, so as to control the position where the single wavelength first polarized light and second linear polarized light of each wavelength are emitted to the dispersion unit.

[0112] The polarization separation unit is also used to transmit the first linear polarized light of a single wavelength from the optical switching engine to the dispersion unit, so that the dispersion unit transmits the first linear polarized light of a single wavelength to the polarization conversion unit; and to transmit the second linear polarized light of a single wavelength from the optical switching engine to the dispersion unit, so that the dispersion unit transmits the second linear polarized light of a single wavelength to the polarization conversion unit.

[0113] The polarization conversion unit is further used to perform polarization conversion on the first linear polarized light of a single wavelength and output it to the corresponding first branch port, and to perform polarization conversion on the second linear polarized light of a single wavelength and output it to the corresponding second branch port.

[0114] In some examples, the polarization conversion unit includes 2 (M+N) polarization conversion components, where the M+N polarization conversion components each correspond to a port in the first port group, and the other M+N polarization conversion components each correspond to a port in the second port group.

[0115] In a first possible implementation, the polarization conversion component includes a birefringent crystal and a half-wave plate.

[0116] In the polarization conversion assembly corresponding to the first common port, a birefringent crystal is used to split a first multi-wavelength optical signal from the corresponding first common port into a first polarization component and a second polarization component, wherein the first polarization component and the second polarization component are linearly polarized light with mutually perpendicular polarization directions. A half-wave plate is used to convert the polarization state of the first polarization component so that the polarization direction of the converted first polarization component is the same as the polarization direction of the second polarization component, thereby converting the first multi-wavelength optical signal into multi-wavelength first linearly polarized light.

[0117] In the polarization conversion assembly corresponding to the second common port, a birefringent crystal is used to split a second multi-wavelength optical signal from the corresponding second common port into a first polarization component and a second polarization component, wherein the first polarization component and the second polarization component are linearly polarized light with mutually perpendicular polarization directions. A half-wave plate is used to convert the polarization state of the second polarization component so that the polarization direction of the converted second polarization component is the same as that of the first polarization component, thereby converting the second multi-wavelength optical signal into multi-wavelength second linearly polarized light.

[0118] In the embodiment of the present application, the birefringent crystal includes but is not limited to yttrium vanadate crystal (YVO4) or calcite.

[0119] In a second possible implementation, the polarization conversion component includes a polarization beam splitter (PBS), a reflector, and a half-wave plate.

[0120] In the polarization conversion assembly corresponding to the first common port, the PBS is used to reflect the first polarization component of the first multi-wavelength optical signal from the corresponding first common port, and to transmit the second polarization component of the first multi-wavelength optical signal from the corresponding first common port, wherein the first polarization component and the second polarization component are linearly polarized lights with polarization directions perpendicular to each other. The reflector is used to receive the first polarization component from the PBS and reflect the first polarization component to a half-wave plate, which is used to convert the polarization state of the first polarization component so that the polarization direction of the converted first polarization component is the same as the polarization direction of the second polarization component, thereby converting the first multi-wavelength optical signal into multi-wavelength first linearly polarized light.

[0121] In the polarization conversion assembly corresponding to the second common port, the PBS is used to reflect the second polarization component of the second multi-wavelength optical signal from the corresponding second common port, and transmit the first polarization component of the second multi-wavelength optical signal from the corresponding second common port, wherein the first polarization component and the second polarization component are linearly polarized lights with polarization directions perpendicular to each other. The reflector is used to receive the second polarization component from the PBS and reflect the second polarization component to a half-wave plate, which is used to convert the polarization state of the second polarization component so that the polarization direction of the converted second polarization component is the same as the polarization direction of the second polarization component, thereby converting the first multi-wavelength optical signal into multi-wavelength first linearly polarized light.

[0122] Illustratively, the first polarization component and the first linear polarized light are both P light, and the second polarization component and the second linear polarized light are both S light; or, the first polarization component and the first linear polarized light are both S light, and the second polarization component and the second linear polarized light are both P light.

[0123] The structure of the polarization conversion assembly corresponding to the first branch port is identical to that of the polarization conversion assembly corresponding to the first common port. However, due to the opposite propagation directions of light, the function of the polarization conversion assembly corresponding to the first branch port is opposite to that of the polarization conversion assembly corresponding to the first common port. For example, when the polarization conversion assembly corresponding to the first branch port receives single-wavelength first linearly polarized light from the dispersion unit, it converts a portion of the single-wavelength first linearly polarized light into single-wavelength second linearly polarized light, and combines the other portion of the single-wavelength first linearly polarized light with the converted single-wavelength second linearly polarized light before outputting the combined light to the corresponding first branch port.

[0124] Similarly, the structure of the polarization conversion component corresponding to the second branch port is the same as that of the polarization conversion component corresponding to the second common port, but since the propagation directions of light are opposite, the function of the polarization conversion component corresponding to the second branch port is opposite to that of the polarization conversion component corresponding to the second common port.

[0125] The embodiments of the present application do not limit the components of the polarization separation unit. For example, the polarization separation unit may include a PBS and a reflector, etc., as long as the functions of the aforementioned polarization separation unit can be achieved.

[0126] It should be noted that FIG3 to FIG7 illustrate an example in which a WSS has two port groups. In other embodiments, the WSS may have more port groups, such as three port groups or four port groups.

[0127] In some examples, the WSS includes four port groups: a first port group, a second port group, a third port group, and a fourth port group. The details of the first and second port groups are described in the corresponding embodiment of FIG3 and are not further described here. The third port group includes M third common ports and N third branch ports. The fourth port group includes M fourth common ports and N fourth branch ports. The arrangement of the M third common ports, N third branch ports, M fourth common ports, and N fourth branch ports is the same as the arrangement of the M first common ports, N first branch ports, M second common ports, and N second branch ports. The arrangement includes the arrangement order, spacing, and light output direction. Thus, in the dispersion direction, each port in the first and second port groups corresponds one-to-one to each port in the third and fourth port groups. Each port group corresponds to a light spot group, each light spot group including multiple light spots arranged in the dispersion direction. The light spot groups corresponding to the four port groups are arranged sequentially in a direction perpendicular to the dispersion direction. This allows the optical switching engine to independently control the optical signals corresponding to the four port groups.

[0128] In the embodiments shown in FIG. 1 to FIG. 7 , the dispersion unit includes a transmissive optical element. In other embodiments, the transmissive optical element may be replaced with a reflective optical element to further reduce the volume of the WSS.

[0129] Figure 8 is a light path diagram of another WSS in the dispersion direction, provided by an embodiment of the present application. Figure 8 is based on the embodiment shown in Figure 1, but the transmissive optical element in the dispersion unit is replaced with a reflective optical element. For other embodiments, the transmissive optical element in the dispersion unit can also be replaced with a reflective optical element. The principle is similar to that of Figure 1 and will not be described in detail here.

[0130] In the above embodiments, the common port is used as the input port and the branch port is used as the output port. However, since the optical path is reversible, the common port can also be the output port and the branch port can also be the input port.

[0131] An embodiment of the present application further provides an optical communication device, comprising a control circuit and the aforementioned WSS, wherein the control circuit is connected to the WSS. The control circuit is configured to control an optical switching engine of the WSS, thereby establishing optical channels between each common port and each branch port of the WSS. Optionally, the optical communication device may be a single board or an optical switching device including the single board, such as an optical switching device such as a ROADM.

[0132] Optical switching equipment can be devices such as ROADMs that switch optical signals. ROADMs enable flexible service scheduling and intelligent O&M for all-optical networks, offering wavelength-level scheduling and multi-dimensional flexible networking capabilities. The following describes the structure of optical communication equipment using ROADMs as an example.

[0133] Figure 9 is a schematic diagram of the structure of a ROADM provided by an embodiment of the present application. As shown in Figure 9, the ROADM includes multiple boards, some of which are located on the line side of Figure 9, and others on the branch side of Figure 9. A board on the branch side connects a transmitter (transmitter, TX) and a receiver (receiver, RX) (not shown). The boards can also implement optical switching. The ROADM utilizes multiple boards to exchange light, thus achieving optical switching in the ROADM.

[0134] Each board includes at least one WSS. Figure 9 illustrates a single board including multiple WSSs. Some WSSs have M input ports and N output ports (expressed as M×N, where M>1 and N>1). The WSS can transmit an optical signal (such as a wavelength-division multiplexed (WDM) signal) from any input port (also known as a common port or a combined port) to any of the N output ports (also known as a branch port or a split-wavelength port). Some WSSs have N input ports and M output ports (expressed as N×M). The WSS can transmit an optical signal from any of the N input ports to any of the M output ports.

[0135] In addition to at least one WSS, the board may also include other components. For example, the board may include a control circuit that controls the WSS to transmit light from its input port to its output port. This control circuit can be used to control the optical switching of the optical switching device.

[0136] By connecting the ports of multiple WSSs, ROADM can transmit optical signals of any wavelength from any input port of the ROADM to any output port of the ROADM.

[0137] Optionally, the ROADM can be colorless, directionless, and contentionless, and is referred to as a CDC ROADM. Colorless means any port can output any wavelength; directionless means any wavelength can be dispatched in any direction; and contentionless means no wavelength conflict occurs when multiple directions simultaneously require the same wavelength to be added or dropped locally.

[0138] Optionally, in Figure 9, the branch side includes an add / drop module, which is connected to optical switching modules of various dimensions on the line side. In other embodiments, the branch side may also include at least two add / drop modules, each of which is connected to optical switching modules of a certain dimension on the line side, with different add / drop modules connected to optical switching modules of different dimensions. The add / drop modules are used to add local wavelengths and transmit the added wavelengths to the optical switching modules on the connected line side; as well as to drop at least some wavelengths from the optical switching modules on the connected line side.

[0139] The optical switching device may also be a device other than a ROADM, and the number of boards in the device may differ from the number of boards in the ROADM, and / or the connection relationship between the boards in the device may differ from the connection relationship between the boards in the ROADM. Therefore, the optical switching device provided in the embodiments of the present application may include multiple boards, and these boards may be connected to each other. The connections between the boards enable optical switching of the optical switching device. In addition to multiple boards, the optical switching device may also include other components. For example, the optical switching device may also include a power module and a heat dissipation module. The power module is used to supply power to the boards, and the heat dissipation module is used to dissipate heat from the boards.

[0140] An embodiment of the present application also provides an optical communication system comprising multiple optical switching nodes. The multiple optical switching nodes can exchange optical signals via optical fibers. The optical switching nodes can include a control device and the aforementioned optical switching device, with the control device configured to control the optical switching device in exchanging optical signals. Optionally, the optical switching nodes can also include electrical switching devices, and the control device can further control the electrical switching devices in exchanging electrical signals.

[0141] Figure 10 is a schematic diagram of the structure of an optical communication system provided in an embodiment of the present application. As shown in Figure 10, the optical communication system includes: a master node, a backup node, and at least one optical transmission link. The master node includes a first WSS, and the backup node includes a second WSS. The first WSS and the second WSS are any of the aforementioned WSSs. Each optical transmission link is connected between a branch port of the first WSS and a branch port of the second WSS. At least one transmission node is sequentially connected to each optical transmission link.

[0142] The first WSS is configured to output a first optical signal from a first target branch port of the first WSS to the second node when the link between the first node and the second node is not disconnected. The second WSS is configured to output a second optical signal from a second target branch port of the second WSS to the second node when the link between the first node and the second node is disconnected. The second optical signal and the first optical signal are both configured to carry information to be sent to the second node.

[0143] The second node is any node in any optical transmission link, the first node is a master node or a transmission node adjacent to the second node in the optical transmission link where the second node is located. The first target branch port is a branch port of the first WSS connected to the optical transmission link where the second node is located, and the second target branch port is a branch port of the second WSS connected to the optical transmission link where the second node is located.

[0144] For example, in Figure 10, circles represent transmission nodes. Assume that the first node is transmission node N1, and the second node is transmission node N2. During a first time period, the link between transmission nodes N1 and N2 is normal, and the master node sends a first optical signal to transmission node N2 via a branch port of the first WSS. During a second time period, the link between transmission nodes N1 and N2 is disconnected, and the backup node sends a second optical signal to transmission node N2 via a branch port of the second WSS.

[0145] Optionally, the wavelengths of the first optical signal and the second optical signal may be the same or different.

[0146] In the embodiment of the present application, a common port COM1 of the first WSS is used to receive optical signals from the line side (not shown in FIG. 10 ) of the master node, another common port COM2 of the second WSS is used to receive local optical signals from the master node (i.e., optical signals sent by local devices), and another common port COM3 of the first WSS serves as a protection port. A common port COM1 of the second WSS is used to receive optical signals from the line side (not shown in FIG. 10 ) of the backup node, another common port COM2 of the second WSS is used to receive local optical signals from the backup node (i.e., optical signals sent by local devices), and another common port COM3 of the second WSS serves as a protection port.

[0147] In an embodiment of the present application, the local device of the master node may include multiple optical transform units (OTUs), each corresponding to a different wavelength. That is, different OTUs are used to transmit optical signals of different wavelengths. The local device of the master node may also include a combiner, which is used to combine the optical signals transmitted by the multiple OTUs into one channel to generate a combined signal, and then transmit the combined signal to the common port COM2 of the first WSS. The structure of the local device of the backup node is similar to that of the local device of the master node and will not be described in detail here.

[0148] The optical communication system also includes a first protection component connected to a local device of the master node and to a protection port COM3 of the second WSS. The first protection component is configured to obtain a first optical signal from a local optical signal transmitted by the local device and output a second optical signal to the protection port of the second WSS.

[0149] In one possible implementation, the first optical signal and the second optical signal have the same wavelength, that is, they are the same optical signal. In this case, it is only necessary to obtain the first optical signal from the common port COM2 of the first WSS and input it to the common port COM3 of the second WSS. The second WSS is then controlled to output the first optical signal received at its common port COM3 from a branch port of the second WSS connected to the optical transmission link where the second node is located.

[0150] Illustratively, in this embodiment, the first protection component may adopt any one of the following structures.

[0151] The first structure, as shown in Figure 10, the first protection component includes a splitter S1, the input end of the splitter S1 is connected to the output end of the local device of the master node, one output end of the splitter S1 is connected to the common port COM2 of the first WSS, and the other output end of the splitter S1 is connected to the common port COM3 of the second WSS.

[0152] The optical splitter S1 is used to split the local optical signal sent by the local device into two paths, one path is sent to the common port COM2 of the first WSS of the master node, and the other path is sent to the common port COM3 of the second WSS of the backup node.

[0153] Continuing with the example of transmission node N1 as the first node and transmission node N2 as the second node, during the first time period, the optical transmission link is normal. The first WSS outputs the first optical signal from its branch port P1 among the local optical signals received at its common port COM2, transmitting it to transmission node N2 via transmission node N1. The second WSS ignores the optical signal received at its common port COM3, meaning that no optical signal received at the second WSS's common port COM3 is output from any of its branch ports.

[0154] In the second time period, an abnormality occurs in the optical transmission link, and the link between transmission node N1 and transmission node N2 is disconnected. The second WSS outputs the first optical signal received by its common port COM3 from the branch port P1 of the second WSS, and transmits it to the transmission node N2 after passing through the transmission node N5, the transmission node N4, and the transmission node N3 in sequence. Whether the second WSS outputs the first optical signal received by its common port COM3 from the branch port P1 of the second WSS is implemented by the control circuit in the standby node. The embodiment of the present application does not limit the way in which the standby node knows whether the optical transmission link is abnormal, and it can be known through automatic detection or manual configuration.

[0155] The second structure, the first protection component, includes a first combiner, a second combiner, and multiple optical switches, with the multiple optical switches corresponding one-to-one to the multiple OTUs. The input of each optical switch is connected to a corresponding OTU, one output of the optical switch is connected to the input of the first combiner, the output of the first combiner is connected to the common port COM2 of the first WSS, the other output of the optical switch is connected to the input of the second combiner, and the output of the second combiner is connected to the common port COM3 of the second WSS. In this way, the optical switch can select whether the corresponding OTU output optical signal is output to the first WSS or the second WSS. The first combiner can be a combiner in the local device of the aforementioned master node.

[0156] Continuing with the example of transmission node N1 as the first node and transmission node N2 as the second node, during the first time period, the optical transmission link is normal. Each optical switch connects the OTU to the input of the first combiner. As a result, the optical signals output by each OTU are transmitted from the first combiner to the common port COM2 of the first WSS. The first WSS then outputs the first optical signal from its branch port P1 among the local optical signals received at its common port COM2, transmitting the signal to transmission node N2 via transmission node N1.

[0157] In the second time period, an abnormality occurs in the optical transmission link, and the link between the transmission node N1 and the transmission node N2 is disconnected. The optical switch connected to the OTU of the wavelength corresponding to the first optical signal connects the OTU to the input end of the second combiner, so that the first optical signal can be transmitted to the common port COM3 of the second WSS through the second combiner. The second WSS outputs the first optical signal received by its common port COM3 from the branch port P1 of the second WSS, and transmits it to the transmission node N2 after passing through the transmission node N5, the transmission node N4, and the transmission node N3 in sequence. The embodiment of the present application does not limit the way in which the master node knows whether the optical transmission link is abnormal, and it can be known through automatic detection or manual configuration.

[0158] This embodiment is applicable to scenarios where the optical signals currently output from the branch port of the second WSS do not contain an optical signal with the same wavelength as the first optical signal. Since an optical signal with the same wavelength can only be output from one branch port of the second WSS at the same time, even if the optical signal output from the first protection component to the protection port of the second WSS (i.e., the common port COM3) contains an optical signal with the same wavelength as the optical signal currently output from the branch port of the second WSS, it will not affect the original optical signal.

[0159] It should be noted that if the optical signal currently output from the branch port of the second WSS contains an optical signal with the same wavelength as the first optical signal, directly switching the first optical signal to the common port COM3 of the second WSS will not allow it to be normally output from the branch port of the second WSS. Therefore, it is necessary to convert the first optical signal into a second optical signal before transmitting it to the common port COM3 of the second WSS. Here, the wavelength of the second optical signal is different from the wavelength of the first optical signal and is different from any wavelength of the optical signals currently output from the branch port of the second WSS.

[0160] In one possible implementation, the master node may include information carried by a first optical signal sent by a first OTU in a local device in a second optical signal sent by a second OTU. In this implementation, the first protection component has a simple structure and low implementation cost.

[0161] In another possible implementation, the first optical signal can be first obtained from the local optical signal of the master node, and then the information carried by the first optical signal can be extracted. Then, a second optical signal can be generated based on the information, and the second optical signal can be input into the common port COM3 of the second WSS, and the second WSS can be controlled to output the second optical signal received by its common port COM3 from the branch port P1 of the second WSS.

[0162] In this embodiment, the first protection component may include an optical splitter, a filter, a light source, a modulator, and a processing circuit. The input of the optical splitter is connected to the output of the local device, and the output of the optical splitter is connected to the input of the filter. The light source is configured to output a light beam having a wavelength corresponding to the second optical signal. The processing circuit is configured to convert the light output by the filter into an electrical signal and, based on the electrical signal, control the modulator to modulate the light beam output by the light source to generate the second optical signal.

[0163] Optionally, the master node and the backup node may be the same optical switching device, or different optical switching devices. When the master node and the backup node are different optical switching devices, the master node and the backup node may be located in the same geographical location, for example, in the same computer room, or the master node and the backup node may be located in different geographical locations, for example, each located in a different computer room.

[0164] In some examples, the master node and the backup node are two different ROADMs. The first WSS is the WSS on the branch side of the master node, and the second WSS is the WSS on the branch side of the backup node. A common port COM1 of the first WSS is used to connect to the line side of the ROADM for receiving optical signals from other nodes. Another common port COM2 of the first WSS is used to connect to a local device (such as an OTU, etc.) for receiving optical signals that the local device needs to send to the transmission device or the backup node. Another common port COM3 of the first WSS serves as a protection port. Similarly, a common port COM1 of the second WSS is used to connect to the line side of the ROADM for receiving optical signals from other nodes. Another common port COM2 of the second WSS is used to connect to a local device (such as an OTU, etc.) for receiving optical signals that the local device needs to send to the transmission device or the master node. Another common port COM3 of the second WSS serves as a protection port for receiving optical signals transmitted by the master node.

[0165] In other examples, the master node and the backup node are the same ROADM. The ROADM has two wavelength switching modules on its branch side, which can also be called local add / drop modules. One of the two wavelength switching modules on the branch side includes a first WSS, and the other includes a second WSS.

[0166] Optionally, the transmission node may be an optical communication device in an optical access network, such as an optical line terminal (OLT).

[0167] Optionally, as shown in Figure 10, the master node further includes a third WSS, and the backup node further includes a fourth WSS. The branch ports of the third WSS correspond one-to-one with the branch ports of the fourth WSS, and an optical transmission link is connected between the corresponding branch ports of the third and fourth WSSs. Because each transmission node needs to transmit optical signals in addition to receiving them, each transmission node in the optical transmission link can transmit optical signals to the line side of the master node via the third or fourth WSS.

[0168] The third WSS is configured to receive a third optical signal from the second node from a third target branch port of the third WSS when the link between the first node and the second node is not disconnected. The fourth WSS is configured to receive a fourth optical signal from the second node from a fourth target branch port of the fourth WSS when the link between the first node and the second node is disconnected. Both the third optical signal and the fourth optical signal are configured to carry information sent by the second node. The third target branch port is a branch port of the third WSS connected to the optical transmission link where the second node is located, and the fourth target branch port is a branch port of the fourth WSS connected to the optical transmission link where the second node is located. Optionally, the wavelengths of the third optical signal and the fourth optical signal may be the same or different.

[0169] In some examples, assume that the first node is transmission node N1 and the second node is transmission node N2. During a third time period, the link between transmission node N1 and transmission node N2 is normal, and transmission node N2 sends a third optical signal to the master node via a branch port of a third WSS. During a fourth time period, the link between transmission node N1 and transmission node N2 is disconnected, and transmission node N2 sends a fourth optical signal to the backup node via a branch port of a fourth WSS.

[0170] Optionally, the first WSS and the third WSS may be integrated together to form a Twin WSS. Similarly, the second WSS and the fourth WSS may be integrated together to form a Twin WSS.

[0171] In the embodiment of the present application, the master node and the backup node are relative. For example, assuming there are a first switching device and a second switching device, the second switching device can be the backup node of the first switching device, and the first switching device can also be the backup node of the second switching device. That is, the first switching device and the second switching device are mutually master and backup. In this case, the optical communication system also includes a second protection component, which is connected to the local device of the backup node, and the second protection component is also connected to the protection port COM3 of the first WSS. The second protection component is also used to obtain a fifth optical signal from the local optical signal sent from the local device of the backup node, and output the sixth optical signal to the protection port COM3 of the first WSS.

[0172] The structure of the second protection component can adopt any one of the structures of the aforementioned first protection component, and detailed description is omitted here.

[0173] During implementation, the first protection component and the second protection component can be integrated into the master node or the backup node; or, part of the first protection component and the second protection component can be integrated into the master node, and the other part of the first protection component and the second protection component can be integrated into the backup node; or, the first protection component and the second protection component can be set independently of the master node and the backup node.

[0174] For example, in FIG10 , the first protection component includes an optical splitter S1, and the first protection component is integrated in the master node; the second protection component includes an optical splitter S2, and the second protection component is integrated in the standby node.

[0175] It should be noted that Figure 10 shows only one optical transmission link. In practical applications, the number of optical transmission links can be greater, such as two or three, as long as the number of optical transmission links is less than or equal to the number of branch ports of the first WSS and the second WSS. In addition, the embodiments of the present application do not limit the number of transmission nodes in each optical transmission link, which can be set according to actual needs. The number of transmission nodes included in different optical transmission links can be the same or different.

[0176] In addition, Figure 10 illustrates an example in which a first protection component is used to protect the common port COM2 of the master node, which is used to receive the master node's local optical signal, and a second protection component is used to protect the common port COM2 of the backup node, which is used to receive the backup node's local optical signal. In other embodiments, the first protection component may be used to protect the common port COM1 of the master node, which is used to receive the master node's line-side optical signal, and / or the second protection component may be used to protect the common port COM1 of the backup node, which is used to receive the backup node's line-side optical signal.

[0177] When the first protection component is used to protect the common port COM1 of the master node, which is used to receive the line-side optical signal of the master node, the first protection component is connected to the common port COM1 of the first WSS and is also connected to the protection port COM3 of the second WSS. The first protection component is used to obtain the first optical signal from the line-side optical signal of the master node and output the second optical signal to the protection port of the second WSS.

[0178] Similarly, when the second protection component is used to protect the common port COM1 of the standby node, which is used to receive the line-side optical signal of the standby node, the second protection component is connected to the common port COM1 of the second WSS and is also connected to the protection port COM3 of the first WSS. The second protection component is configured to obtain the first optical signal from the line-side optical signal of the standby node and output the second optical signal to the protection port of the first WSS.

[0179] An embodiment of the present application further provides an optical communication method, which is implemented based on the aforementioned optical communication system. The master node and backup node of the optical communication system each include a control circuit. The control circuit of the master node is electrically connected to a first WSS and is used to control the optical switching engine of the first WSS. The control circuit of the backup node is electrically connected to a second WSS and is used to control the optical switching engine of the second WSS. The method can be implemented by the control circuit.

[0180] In some examples, the method includes: when a link between the first node and the second node is not disconnected, outputting the first optical signal from a first target branch port of the first WSS to the second node through the first WSS; or, when the link between the first node and the second node is disconnected, outputting the second optical signal from a second target branch port of the second WSS to the second node through the second WSS.

[0181] In other examples, the method includes: when the link between the first node and the second node is not disconnected, receiving, through the third WSS, a third optical signal from the second node received from a third target branch port of the third WSS; or, when the link between the first node and the second node is disconnected, receiving, through the fourth WSS, a fourth optical signal from the second node received from a fourth target branch port of the fourth WSS.

[0182] In some other examples, the method includes: when the link between the first node and the second node is not disconnected, outputting the first optical signal from the first target branch port of the first WSS to the second node through the first WSS, and receiving the third optical signal from the second node received from the third target branch port of the third WSS through the third WSS; or, when the link between the first node and the second node is disconnected, outputting the second optical signal from the second target branch port of the second WSS to the second node through the second WSS, and receiving the fourth optical signal from the second node received from the fourth target branch port of the fourth WSS through the fourth WSS.

[0183] For details, please refer to the aforementioned embodiment of the optical communication system and will not be described in detail here.

[0184] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meaning understood by persons of ordinary skill in the field to which this application belongs. The words "first", "second", "third" and similar terms used in the patent application specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "a" do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as "include" or "comprising" mean that the elements or objects appearing before "include" or "comprising" cover the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. The multiple involved in the embodiments of this application refers to two or more. A and / or B means that there are three situations: A; B; and A and B.

[0185] The above is only an embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A wavelength selective switch, characterized in that: The wavelength selective switch comprises: a first port group, a dispersion unit and an optical switching engine, The first port group includes: M first common ports and N first branch ports, wherein M is an integer greater than 2, and N is an integer greater than 1, and the M first common ports are respectively used to provide a first multi-wavelength optical signal to the dispersion unit; The dispersion unit is used to divide the first multi-wavelength optical signal from the first common port into a plurality of first single-wavelength optical signals according to wavelength, and transmit the plurality of first single-wavelength optical signals to different positions of the optical switching engine in the dispersion direction respectively; The optical switching engine is used to transmit the plurality of first single-wavelength optical signals from the dispersion unit to the dispersion unit, so as to transmit at least one first single-wavelength optical signal among the plurality of first single-wavelength optical signals to one of the first branch ports through the dispersion unit; When there are at least two first single-wavelength optical signals with the same wavelength among the multiple first single-wavelength optical signals transmitted by the dispersion unit to the optical switching engine, the optical switching engine transmits any one of the at least two first single-wavelength optical signals with the same wavelength to the first branch port.

2. The wavelength selective switch according to claim 1, characterized in that: The M first common ports and the N first branch ports are arranged along a first direction, and a distance between any two of the first common ports is greater than a distance between any two of the first branch ports.

3. The wavelength selective switch according to claim 2, characterized in that: Among the M first common ports, the distance between any pair of the first common ports is a first distance, except that the distance between any first common port of the pair of the first common ports and any first branch port is a second distance, and the first distance is not equal to the second distance.

4. The wavelength selective switch according to claim 2 or 3, characterized in that: The N first branch ports are located between two adjacent first common ports; or, There is one first common port among the N first branch ports.

5. The wavelength selective switch according to any one of claims 2 to 4, characterized in that: The wavelength selective switch further comprises: a second port group, The second port group includes: M second common ports and N second branch ports; The M second common ports are respectively used to provide a second multi-wavelength optical signal to the dispersion unit; The dispersion unit is further used to divide the second multi-wavelength optical signal from the second common port into a plurality of second single-wavelength optical signals according to wavelength, and transmit the plurality of second single-wavelength optical signals to different positions of the optical switching engine in the dispersion direction respectively, and the first single-wavelength optical signal and the second single-wavelength optical signal with the same wavelength are respectively transmitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction; The optical switching engine is further used to transmit the plurality of second single-wavelength optical signals from the dispersion unit to the dispersion unit, so that at least one second single-wavelength optical signal among the plurality of second single-wavelength optical signals is transmitted to one of the second branch ports; When there are at least two second single-wavelength optical signals with the same wavelength among the multiple second single-wavelength optical signals transmitted by the dispersion unit to the optical switching engine, the optical switching engine transmits one of the at least two second single-wavelength optical signals with the same wavelength to the branch port.

6. The wavelength selective switch according to claim 5, characterized in that: The M second common ports, the N second branch ports, the M first common ports and the N first branch ports are arranged along the first direction, and a distance between any two of the second common ports is greater than a distance between any two of the second branch ports.

7. The wavelength selective switch according to claim 6, characterized in that: The N first branch ports are located between two adjacent first common ports, and the N second branch ports are located between two adjacent first common ports and between two adjacent second common ports; There is one first common port between the N second branch ports and the N first branch ports.

8. The wavelength selective switch according to claim 6, characterized in that: The M second common ports and the M first common ports are arranged symmetrically about a reference plane, the N first branch ports and the N second branch ports are arranged symmetrically about the reference plane, and the reference plane is parallel to the dispersion direction and perpendicular to the first direction.

9. The wavelength selective switch according to any one of claims 5 to 8, characterized in that: The light emitting directions of the M first common ports and the N first branch ports are parallel, the light emitting directions of the M second common ports and the N second branch ports are parallel, and the light emitting directions of the M first common ports form an acute angle with the light emitting directions of the M second common ports.

10. The wavelength selective switch according to any one of claims 5 to 9, characterized in that: The wavelength selective switch further comprises: a polarization conversion unit and a polarization separation unit, The polarization conversion unit is located on an optical path between the first port group and the dispersion unit, and is located on an optical path between the second port group and the dispersion unit, and is used to convert the first multi-wavelength optical signal provided by the first port group into a first linear polarized light, and transmit the first linear polarized light to the dispersion unit; and convert the second multi-wavelength optical signal provided by the second port group into a second linear polarized light, and transmit the second linear polarized light to the dispersion unit; The dispersion unit is used to emit the first linear polarized light and the second linear polarized light with the same wavelength to the same position of the polarization separation unit in the dispersion direction; The polarization separation unit is located on the optical path between the dispersion unit and the optical switching engine, and is used to emit the first linear polarized light and the second linear polarized light of the same wavelength emitted by the dispersion unit to different positions of the optical switching engine perpendicular to the dispersion direction; Wherein, the polarization direction of the first linear polarized light is perpendicular to the polarization direction of the second linear polarized light.

11. An optical communication device, characterized in that: The method comprises a control circuit and the wavelength selective switch according to any one of claims 1 to 10, wherein the control circuit is connected to the wavelength selective switch.

12. An optical communication system, characterized in that: The optical communication system comprises: a master node, a backup node and at least one optical transmission link; Wherein, the master node includes a first wavelength selective switch, the backup node includes a second wavelength selective switch, and the first wavelength selective switch and the second wavelength selective switch are the wavelength selective switches according to any one of claims 1 to 10; Each of the optical transmission links comprises at least one node, and the optical transmission link is connected between a branch port of the first wavelength selective switch and a branch port of the second wavelength selective switch; The first wavelength selective switch is used to output the first optical signal from the first target branch port of the first wavelength selective switch to the second node when the link between the first node and the second node is not disconnected; The second wavelength selective switch is used to output a second optical signal from a second target branch port of the second wavelength selective switch to the second node when a link between the first node and the second node is disconnected, wherein the second optical signal and the first optical signal are both used to carry information sent to the second node; The second node is any node in an optical transmission link, the first node is the main node or a transmission node adjacent to the second node in the optical transmission link where the second node is located, the first target branch port is a branch port of the first wavelength selection switch connected to the optical transmission link where the second node is located, and the second target branch port is a branch port of the second wavelength selection switch connected to the optical transmission link where the second node is located.

13. The optical communication system according to claim 12, characterized in that: The first optical signal and the second optical signal have different wavelengths.

14. The optical communication system according to claim 12 or 13, characterized in that: The first wavelength selective switch has a common port for receiving a line-side optical signal of the master node and a common port for receiving a local optical signal of the master node; The second wavelength selective switch has a protection port, a common port for receiving a line-side optical signal of a standby node, and a common port for receiving a local optical signal of the standby node; The optical communication system further comprises a first protection component, the first protection component and the first wavelength selection switch for receiving the master node The first protection component is connected to at least one of a common port of a line-side optical signal and an output terminal of a local device of the master node, and the first protection component is also connected to a protection port of the second wavelength selective switch; The first protection component is used to obtain the first optical signal from the common port of the first wavelength selective switch for receiving the line-side optical signal of the main node or to obtain the first optical signal from the local optical signal of the main node, and to input the second optical signal into the protection port of the second wavelength selective switch.

15. The optical communication system according to claim 14, characterized in that: The first protection component includes an optical splitter, an input end of the optical splitter is connected to an output end of a local device of the master node, one output end of the optical splitter is connected to a common port of the first wavelength selective switch for receiving a local optical signal of the master node, and another output end of the optical splitter is connected to a protection port of the second wavelength selective switch; or, The first protection component includes a first combiner, a second combiner and a plurality of optical switches, wherein an input end of the optical switch is connected to a wavelength conversion unit in a local device of the master node, an output end of the optical switch is connected to an input end of the first combiner, an output end of the first combiner is connected to a common port of the first wavelength selective switch for receiving a local optical signal of the master node, another output end of the optical switch is connected to an input end of the second combiner, and an output end of the second combiner is connected to a protection port of the second wavelength selective switch.

16. The optical communication system according to any one of claims 12 to 15, characterized in that: The master node further includes a third wavelength selective switch, the backup node further includes a fourth wavelength selective switch, and the optical transmission link is further connected between a branch port of the third wavelength selective switch and a branch port of the fourth wavelength selective switch; The third wavelength selective switch is used to receive a third optical signal from the second node through a third target branch port of the third wavelength selective switch when the link between the first node and the second node is not disconnected; The fourth wavelength selective switch is used to receive a fourth optical signal from the second node through a fourth target branch port of the fourth wavelength selective switch when the link between the first node and the second node is disconnected; The third target branch port is a branch port of the third wavelength selective switch connected to the optical transmission link where the second node is located, and the fourth target branch port is a branch port of the fourth wavelength selective switch connected to the optical transmission link where the second node is located.

17. A method for transmitting an optical signal, characterized in that: Applied to the optical communication system according to any one of claims 12 to 16, the method comprising: When the link between the first node and the second node is not disconnected, outputting the first optical signal from the first target branch port of the first wavelength selective switch to the second node through the first wavelength selective switch; or, When the link between the first node and the second node is disconnected, the second optical signal is output from the second target branch port of the second wavelength selective switch to the second node through the second wavelength selective switch.

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