WO2025112569A1 - Wavelength selective switch, optical communication device and system, and optical signal transmission method - Google Patents

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

This application claims priority to Chinese patent application No. 202311612735.5 filed on November 27, 2023, with invention name “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

The present application relates to the field of optical communication technology, and in particular to a wavelength selective switch (WSS), optical communication equipment, system and optical signal transmission method.

Background Art

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).

In the related art, WSS includes a port group, a dispersion unit, a primary switching engine, and a secondary switching engine. Among them, the port group includes multiple common ports and multiple branch ports. After the light from different common ports passes through the dispersion unit, independent wavelength groups are formed in different areas of the primary switching engine, and different wavelength groups correspond to different common ports. The primary switching engine can perform a separate deflection process on each single-wavelength optical signal in each wavelength group so that it is transmitted to the secondary optical switching engine. Finally, the output port of each single-wavelength optical signal is controlled by the secondary switching engine. The WSS can transmit an optical signal of any wavelength provided by any public port to any branch port.

However, the WSS needs to include two-stage switching engines, has a relatively complex structure, and has a relatively high cost.

Summary of the invention

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.

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, 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. 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.

Wherein, when there are at least two first single-wavelength optical signals with the same wavelength among the multiple first single-wavelength optical signals transmitted from 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. That is, when there are first single-wavelength optical signals with the same wavelength among the first multi-wavelength optical signals incident from different first common ports, the first single-wavelength optical signals with the same wavelength will be transmitted to the same position of the optical switching engine, and the optical switching engine will only emit the first single-wavelength optical signal among the first multi-wavelength optical signals incident from one first common port from the first branch port.

The WSS can realize a WSS with more than three public ports through a primary switching engine, has a simple structure, and has a low manufacturing cost. In addition, the WSS with more than three public ports can improve the flexibility of optical communication system networking.

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 that mirror image crosstalk between the first branch ports can be avoided.

Optionally, among the M first common ports, the distance between any pair of the first common ports is the first distance, except that the distance between any first common port of the any pair of the first common ports and any first branch port is the second distance, and the first distance is not equal to the second distance. In this way, it is possible to avoid the occurrence of mirror crosstalk between any first common port of the any pair of the first common ports and the first branch port.

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 ways:

Mode 1: the N first branch ports are located between two adjacent first common ports;

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

Both of these two methods can easily satisfy the required distance relationship between the first common port and the first branch port.

Optionally, the WSS also 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 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. 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.

Wherein, when there are at least two second single-wavelength optical signals of the same wavelength in 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 there are second single-wavelength optical signals of the same wavelength in the second multi-wavelength optical signals incident from different second common ports, the second single-wavelength optical signals of the same wavelength will be transmitted to the same position of the optical switching engine, and the optical switching engine will only emit the second single-wavelength optical signal in the second multi-wavelength optical signals incident from one second common port from the second branch port. Moreover, 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, so that the other two WSSs can be integrated together to obtain a twin WSS.

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 the distance between any two of the second common ports is greater than the distance between any two of the second branch ports. The ports in the first port group and the second port group are arranged in a row, and the distance between any two of the second common ports is greater than the distance between any two of the second branch ports, so that there is no mirror crosstalk between the second branch ports.

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. There is one first common port between the N second branch ports and the N first branch ports. This arrangement can make full use of the space between the first common ports, which is conducive to further reducing the volume of the WSS.

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

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 with the same wavelength on the optical switching engine are arranged in a direction perpendicular to the dispersion direction.

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 is located 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 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 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 the polarization separation unit 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.

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 include a single board integrating a control circuit and the WSS.

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

The master node includes a first WSS, the backup node includes a second WSS, and the first WSS and the second WSS are any of the above A WSS. 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 used 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 used 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 the second optical signal and the first optical signal are both used to carry information sent to the second node.

Among them, 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.

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 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.

Optionally, the wavelengths of the first optical signal and the second optical signal are different. When there is no optical signal with the same wavelength as the first optical signal among the optical signals currently used by the second WSS, the first optical signal can be directly transmitted to the protection port of the second WSS; and when there is an optical signal with the same wavelength as the first optical signal among the optical signals currently used by the second WSS, the first optical signal needs to be converted into a second optical signal with a wavelength different from the first optical signal and different from any wavelength in the optical signals currently used by the second WSS, and then the second optical signal is 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.

Optionally, the optical communication system further comprises a first protection component, the first protection component is connected to a common port of the first WSS for receiving a line-side optical signal of the master node or to an output end of a local device of the master node, and the first protection component is also connected to a protection port of the second WSS. The first protection component is used to obtain the first optical signal from the common port of the first WSS for receiving a line-side optical signal of 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.

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

In the first type, 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, and 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 has a simple structure and is easy to implement.

The second type, the first protection component includes a first combiner, a second combiner and a plurality of optical switches, 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.

Optionally, the master node further includes a third WSS, the standby 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 used 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 used 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.

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

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

In a fourth aspect, an optical signal transmission method is further provided, and the method is implemented based on any optical communication system provided in the third aspect. The method includes controlling the first WSS to output the first optical signal from the 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, when the link between the first node and the second node is disconnected, controlling the second WSS to output the second optical signal from the second target branch port of the second WSS to the second node.

The effects of the second to fourth aspects mentioned above can refer to the corresponding effects in the first aspect, and this application will not be repeated 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 common ports, the optical signal corresponding to the second node can be input from a first common port 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

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

2 is a schematic diagram of the distribution of light spots of a plurality of first single-wavelength optical signals on an optical switching engine provided by an embodiment of the present application;

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

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

5 is a schematic diagram of light spot distribution of a plurality of first single-wavelength optical signals and a plurality of second single-wavelength optical signals on an optical switching engine provided by an embodiment of the present application;

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

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

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

FIG9 is a schematic diagram of the structure of an optical communication device provided in an embodiment of the present application;

FIG. 10 is a schematic diagram of the structure of an optical communication system provided in an embodiment of the present application.

DETAILED DESCRIPTION

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

The embodiment of the present application provides a WSS with a simple structure and multiple common ports, which 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 in conjunction with FIG.

Figure 1 is an optical path diagram of a WSS in a 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 the present 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.

FIG1 takes a WSS having three common ports and four branch ports as an example for illustration. As shown in FIG1 , 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. Among them, the three first common ports COM11 to COM13 and the four first branch ports P11 to P14 form 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 the embodiment of the present application does not limit this.

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

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

FIG2 is a schematic diagram of the light spot distribution of multiple first single-wavelength optical signals on the optical switching engine provided in an embodiment of the present application. As shown in FIG2, different ellipses represent light spots formed by different first single-wavelength optical signals on the optical switching engine. It can be seen that 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, respectively. However, 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.

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.

The optical switching engine can control the emission angle of the first single-wavelength optical signal on the optical switching engine according to the first branch port to which each first single-wavelength optical signal needs to be transmitted, so that after the first single-wavelength optical signal is emitted from the optical switching engine, it is transmitted to the first single-wavelength optical signal through the dispersion unit. The first branch port to which the wavelength optical signal needs to be transmitted. That is, the optical switching engine achieves displacement of the first single wavelength optical signal in the port direction by controlling the emission angle of the first single wavelength optical signal on the optical switching engine.

As shown in Fig. 1, it is assumed that the plurality of first multi-wavelength optical signals include three first single-wavelength optical signals with wavelengths of 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 emission 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 need to be transmitted.

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

The optical switching engine may be a device such as liquid crystal on silicon (LCOS) or micro-electro-mechanical system (MEMS) that can control the exit angle of incident light. For any first single-wavelength optical signal, the optical switching engine may load a grating, and diffract the first single-wavelength optical signal through the grating to achieve control of the exit angle of the first single-wavelength optical signal.

The periodic direction of the grating loaded on the optical switching engine is the port direction x. The control of the exit angle of the first single-wavelength optical signal on the optical switching engine by the grating follows the grating equation Λsinθ＝λ, where Λ represents the period of the grating, sin represents the sine function, θ represents the deflection angle of the exit 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.

It can be known from the above grating equation that for two first single-wavelength optical signals (with different wavelengths) transmitted from the same first common port to two positions in the dispersion direction of the optical switching engine, if the 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 the two positions 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, when the deflection angles are the same, the optical switching engine will emit the two first single-wavelength optical signals in the same exit direction, so that the two first single-wavelength optical signals can be transmitted to the same first branch port.

For two first single-wavelength optical signals (with different wavelengths) transmitted from different first common ports to two positions in the dispersion direction of the optical switching engine, if the 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 the two positions to control the deflection angle of the exit angle of the two first single-wavelength optical signals on the optical switching engine relative to the reflection angle. Since 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.

It can be seen that 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. Multiple first single-wavelength optical signals output from the same first branch port are combined into a combined optical signal, and the wavelengths of the first single-wavelength optical signals constituting the combined optical signal are different.

When the first single-wavelength optical signals of the first wavelength are obtained by dispersing the first multi-wavelength optical signals incident on the two first common ports through the dispersion unit, there are first single-wavelength optical signals of the first wavelength in both cases, 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. Since the incident angles of the 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 in different emission directions, so that when the two first single-wavelength optical signals of the first wavelength arrive at the port position, the positions in the port direction x are different. It can be seen that when the first multi-wavelength optical signals incident on different first common ports have the same wavelength, the optical switching engine can only emit the first single-wavelength optical signal of the first multi-wavelength optical signal incident from one first common port from the target branch port. Here, the target branch port is one of the multiple first branch ports.

Since the angle 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 angle 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 position, 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, there may be a situation where the two first wavelength first single wavelength optical signals are emitted from one first branch port respectively. This situation is called mirror crosstalk.

For example, for the WSS shown in FIG. 1 , it is assumed 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 branch port P12, then when the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM11 is emitted from the first branch port P11, the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM13 will be emitted from the first branch port P12.

In order to avoid the phenomenon of mirror crosstalk, the arrangement positions of the 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.

Exemplarily, the M first common ports and the N first branch ports may be arranged along the first direction (i.e., the 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 required first branch port, the other first single-wavelength optical signal will be deflected outside the receiving range of the N first branch ports, thereby achieving 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.

Still taking FIG. 1 as an example, it is assumed 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. Since 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 a wavelength of λ1 from the first common port COM11 is emitted from the first branch port P11, the first single-wavelength optical signal with a wavelength of λ1 from the first common port COM13 will be emitted from the position below the first branch port P14. Since this position is outside the receiving range of the first branch ports P11 to P14, no mirror crosstalk phenomenon will occur.

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 required. Optionally, the arrangement of the M first common ports and the N first branch ports includes but is not limited to the following two.

The first arrangement: N first branch ports are located between two adjacent first common ports. For example, as shown in FIG2 , 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 the two first common ports on both sides of the N first branch ports must be greater than the distance between any two of the first branch ports. In this way, it is only necessary to ensure that the distance between the adjacent first common ports is greater than the distance between the two first branch ports with the longest distance to avoid the occurrence of mirror crosstalk between the first branch ports, which is easy to implement.

The second arrangement mode: 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 there is a first common port between the two first part ports. For example, referring to FIG. 2 , 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.

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 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 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. At this time, there will also be the problem of mirror crosstalk.

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 the first distance, the distance from any first common port other than the pair of first common ports to any first branch port is the 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.

Continuing with FIG. 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 crosstalk problem can be avoided.

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 first When the two distances are met at the same time, mirror crosstalk can be better avoided.

For example, in Fig. 1, 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 the first distance is not equal to the second distance.

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 avoid the mirror crosstalk problem of the common port by the above method.

1, the light emitting direction of the first common ports COM11-COM13 is parallel to the main optical axis of the dispersion unit, and the light receiving direction of the first branch ports P11-P14 is also parallel to the main optical axis of the dispersion unit. In other embodiments, the light emitting direction of the first common ports COM11-COM13 may intersect with the main optical axis of the dispersion unit.

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 the wavelength.

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 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 then guide it 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.

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.

In some examples, the first lens group includes a first lens, the dispersion unit is located at the back focal plane of the first lens, the second lens group includes a second lens, the dispersion unit is located at the front focal plane of the second lens, and the optical switching engine is located at the back focal plane of the second lens.

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.

In summary, the WSS can realize a WSS with more than three public ports through a primary switching engine, has a simple structure, and has a low manufacturing cost. In addition, the WSS with more than three public ports can improve the flexibility of optical communication system networking.

In Figures 1 and 2, a WSS including one port group is used as an example for description. In other embodiments, a WSS may have multiple port groups, and the following description is given by taking a WSS having two port groups as an example. Such a WSS integrating two port groups may be called a twin WSS.

FIG3 is a light path diagram of a WSS in a port direction x provided in an embodiment of the present application, and FIG4 is a light path diagram of a WSS in a dispersion direction y provided in an embodiment of the present application. The light path diagram of the WSS in 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.

In conjunction with Figures 3 and 4, the WSS provided in the embodiment 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.

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 the relevant content of FIG. 1 , and the detailed description is omitted here.

The dispersion unit is also used to divide the second multi-wavelength optical signal from the second port group into a plurality of second single-wavelength optical signals according to the wavelength, and transmit the plurality of second single-wavelength optical signals to different positions of the optical switching engine in the dispersion direction. The optical switching engine is also used 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. Wherein, when there are at least two second single-wavelength optical signals of the same wavelength in the multi-channel 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 there are second single-wavelength optical signals of the same wavelength in the second multi-wavelength optical signals incident from different second common ports, the second single-wavelength optical signals of the same wavelength will be transmitted to the same position of the optical switching engine, and the optical switching engine will only emit the second single-wavelength optical signal in the second multi-wavelength optical signal incident from one second common port from the second branch port. Here, the control method of the optical switching engine for the output port of the second single-wavelength optical signal can refer to the control method for the output port of the first single-wavelength optical signal, which will not be described in detail here.

In addition, the first single-wavelength optical signal and the second single-wavelength optical signal having the same wavelength are respectively transmitted by the dispersion unit to the optical switching engine at a direction perpendicular to the Different positions in the dispersion direction.

FIG5 is a schematic diagram of the distribution of light spots 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, respectively) 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, respectively) 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.

Since the first single-wavelength optical signal and the second single-wavelength optical signal of the same wavelength are transmitted to different positions of the optical switching engine perpendicular to the dispersion direction y, the optical switching engine processes the first single-wavelength optical signal and the second single-wavelength optical signal independently. In this way, the first port group and the second port group can share the dispersion unit and the optical switching engine, which is conducive to obtaining a twin WSS with a simple structure and a small size.

In the embodiment of the present application, M second common ports, N second branch ports, M first common ports and N first branch ports are arranged along the first direction, and the distance between any two second common ports is greater than the distance between any two second branch ports. In this way, 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 required first branch port, the other second single-wavelength optical signal will be deflected outside the receiving range of the N second branch ports, so 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.

Optionally, the M second common ports and the N second branch ports may also satisfy the following condition: assuming that the distance between any pair of second common ports is the third distance, the distance from any second common port other than the pair of second common ports to any second branch port is the 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. In this way, mirror crosstalk can be further avoided.

Exemplarily, 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. In order to satisfy 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 will be relatively large, and the ports in the first port group and the ports in the second port group are arranged alternately, which can effectively utilize space and help reduce the volume of the WSS.

For example, as shown in Fig. 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.

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.

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

In order to obtain the light spot distribution position in FIG5, 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 FIG3) between the light emitting directions of the first common port and the second common port is an acute angle. By controlling the light emitting directions of the first common port and the second common port, the light spot positions of the first single-wavelength optical signal and the second single-wavelength optical signal on the optical switching engine can be controlled.

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 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.

The implementation of the first lens group, the second lens group, the dispersion unit and the optical switching engine refers to the relevant description in FIG1 , and the detailed description is omitted here.

In the embodiment of the present application, the specific value of α can be determined according to the structural parameters of the lens in the switching direction (i.e., the port direction x), and the lens in the switching direction can convert the difference in the incident angle into the difference in the position perpendicular to the dispersion direction y of the optical switching engine. As long as it can be ensured that the arrangement direction of the 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.

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 symmetrical with respect to the reference plane are also symmetrical with respect to the reference plane.

In the embodiments shown in FIG3 and FIG4, by controlling the light emitting directions of the first common port and the second common port, the single-wavelength optical signals corresponding to the first common port and the second common port form light spots in different areas of the optical switching engine. In other embodiments, the polarization state of light can also be used to form light spots in different areas of the optical switching engine for the single-wavelength optical signals corresponding to the first common port and the second common port, and this method is described below in conjunction with FIG6 and FIG7.

Fig. 6 is a light path diagram of another WSS in the port direction provided by an embodiment of the present application. Fig. 7 is a light path diagram of the WSS in Fig. 6 in the dispersion direction y. As shown in Figs. 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.

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 is located 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 a first linear polarized light of multiple wavelengths, and transmit the first linear polarized light of multiple wavelengths to the dispersion unit; and to convert the second multi-wavelength optical signal provided by the second port group into a second linear polarized light of multiple wavelengths, and transmit the second linear polarized light of multiple wavelengths to the dispersion unit. Wherein, the polarization direction of the first linear polarized light is perpendicular to the polarization direction of the second linear polarized light.

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 the wavelength, 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 the wavelength, 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 with 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 , and it is only necessary to replace the first single-wavelength optical signal in FIG5 with the single-wavelength first linear polarized light, and replace the second single-wavelength optical signal in FIG5 with the single-wavelength second linear polarized light.

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 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 y.

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

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.

The polarization conversion unit is also used for performing polarization conversion on the first linear polarized light of a single wavelength and outputting it to the corresponding first branch port, and performing polarization conversion on the second linear polarized light of a single wavelength and outputting it to the corresponding second branch port.

In some examples, the polarization conversion unit includes 2 (M+N) polarization conversion components, wherein the M+N polarization conversion components correspond to one port in the first port group respectively, and the other M+N polarization conversion components correspond to one port in the second port group respectively.

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

In the polarization conversion component corresponding to the first common port, the birefringent crystal is used to separate the 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 lights with polarization directions perpendicular to each other. The 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 a multi-wavelength first linearly polarized light.

In the polarization conversion component corresponding to the second common port, the birefringent crystal is used to separate the 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 lights with polarization directions perpendicular to each other. The 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.

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

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

In the polarization conversion component corresponding to the first common port, the PBS is used to reflect the first polarization component in the first multi-wavelength optical signal from the corresponding first common port, and transmit the second polarization component in the first multi-wavelength optical signal from the corresponding first common port, wherein the first polarization component and the second polarization component are linear 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 the half-wave plate, and the 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 linear polarized light.

In the polarization conversion component corresponding to the second common port, the PBS is used to reflect the second polarization component in the second multi-wavelength optical signal from the corresponding second common port, and transmit the first polarization component in the second multi-wavelength optical signal from the corresponding second common port, wherein the first polarization component and the second polarization component are linear 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 the half-wave plate, and the 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 the polarization direction of the second polarization component, thereby converting the first multi-wavelength optical signal into multi-wavelength first linear polarized light.

Exemplarily, 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.

The structure of the polarization conversion component corresponding to the first branch port is the same as that of the polarization conversion component corresponding to the first common port, but because the propagation directions of the light are opposite, the function of the polarization conversion component corresponding to the first branch port is opposite to that of the polarization conversion component corresponding to the first common port. For example, when the polarization conversion component corresponding to the first branch port receives a single-wavelength first linear polarized light from the dispersion unit, a part of the single-wavelength first linear polarized light is converted into a single-wavelength second linear polarized light, and another part of the single-wavelength first linear polarized light and the converted single-wavelength second linear polarized light are combined and output to the corresponding first branch port.

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.

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.

It should be noted that FIG. 3 to FIG. 7 are described by taking the WSS having two port groups as an example. In other embodiments, the WSS may also have more port groups, such as 3 port groups or 4 port groups.

In some examples, the WSS includes four port groups, namely, a first port group, a second port group, a third port group, and a fourth port group. For the relevant contents of the first port group and the second port group, see the corresponding embodiment of FIG. 3, which will not be repeated 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 order of the M third common ports, the N third branch ports, the M fourth common ports, and the N fourth branch ports is the same as the arrangement of the M first common ports, the N first branch ports, the M second common ports, and the N second branch ports. Here, the arrangement includes the arrangement order, the spacing distance, and the light output direction. In this way, in the dispersion direction, each port in the first port group and the second port group corresponds to each port in the third port group and the fourth port group one by one. Each port group corresponds to a light spot group, and each light spot group includes a plurality of light spots arranged in the dispersion direction. The light spot groups corresponding to the four port groups are arranged in sequence in a direction perpendicular to the dispersion direction, so that the optical switching engine can control the optical signals corresponding to the four port groups separately.

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.

FIG8 is a light path diagram of another WSS in the dispersion direction provided by an embodiment of the present application. FIG8 is obtained by replacing the transmissive optical element in the dispersion unit with a reflective optical element based on the embodiment shown in FIG1. For other embodiments, the transmissive optical element in the dispersion unit may also be replaced with a reflective optical element. The principle is similar to that of FIG1 and will not be described in detail here.

In the above embodiments, the common port is used as the input port and the branch port is used as the output port. It is understandable that, 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.

The embodiment of the present application also provides an optical communication device, which includes a control circuit and the aforementioned WSS, wherein the control circuit is connected to the WSS. The control circuit is used to control the optical switching engine of the WSS, so as to establish 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.

Optical switching equipment can be equipment such as ROADM that can exchange optical signals. Among them, ROADM can realize flexible scheduling and intelligent operation and maintenance of all-optical network services, and has wavelength-level scheduling and multi-dimensional flexible networking capabilities. The following takes ROADM as an example to exemplify the structure of optical communication equipment.

FIG9 is a schematic diagram of the structure of a ROADM provided in an embodiment of the present application. As shown in FIG9 , the ROADM includes a plurality of boards, some of which are located on the line side in FIG9 , and the other boards are located on the branch side in FIG9 . A board on the branch side connects a transmitter (transmitter, TX) and a receiver (receiver, RX) (not shown). The board can also realize optical switching. The ROADM realizes optical switching of the ROADM by using the optical switching of the plurality of boards therein.

Each single board includes at least one WSS. FIG9 shows an example of a single board including multiple WSSs. Some WSSs have M input ports and N output ports (expressed as M×N, M＞1 and N＞1). The WSS can transmit an optical signal (such as a wavelength-division multiplex (WDM) signal) from any input port (also called a common port or a combined wave port) to any output port of the N output ports (also called a branch port or a split wave port). Some WSSs have N input ports and M output ports (expressed as N×M). The WSS can transmit an optical signal from any input port of the N input ports to any one of the M output ports.

In addition to at least one WSS, the board may also include other components. For example, the board may also include a control circuit, which is used to control the WSS to transmit light from the input port to the output port. The control of the optical switching of the optical switching device can be achieved by controlling the control circuit.

By connecting the ports of multiple WSSs, ROADM can transmit an optical signal of any wavelength at any input port of the ROADM to any output port of the ROADM.

Optionally, the ROADM may be a ROADM with colorless, directionless, and contentionless characteristics, and such a ROADM may be referred to as a CDC ROADM. Colorless means that any port can output any wavelength; directionless means that any wavelength can be dispatched to any direction; contentionless means that when multiple directions need to add or remove the same wavelength locally at the same time, no wavelength conflict will occur.

Optionally, in FIG9 , the branch side includes an up/down module, which is respectively connected to the optical switching modules of various dimensions on the line side. In other embodiments, the branch side may also include at least two up/down modules, each of which is connected to an optical switching module of a certain dimension on the line side, and the optical switching modules connected to different up/down modules have different dimensions. The up/down modules are used to add local wavelengths and transfer the added wavelengths to the optical switching modules on the connected line side; and to drop at least part of the wavelengths from the optical switching modules on the connected line side.

The optical switching device may also be a device other than ROADM, and the number of boards in the device is different from the number of boards in the ROADM, and/or the connection relationship between the boards in the device is different from the connection relationship between the boards in the ROADM. Therefore, the optical switching device provided in the embodiment of the present application may include multiple boards, and there is a connection relationship between these boards. Through the connection between the boards, optical switching of the optical switching device can be achieved. In addition to multiple boards, the optical switching device may also include other components. For example, the optical switching device also includes a power module and a heat dissipation module, etc. The power module is used to supply power to the board, and the heat dissipation module is used to dissipate heat from the board.

The embodiment of the present application also provides an optical communication system, which includes multiple optical switching nodes. Multiple optical switching nodes can exchange optical signals through optical fibers. Among them, the optical switching node may include a control device and the aforementioned optical switching device, and the control device is used to control the optical switching device to exchange optical signals. Optionally, the optical switching node may also include an electrical switching device, and the control device may also control the electrical switching device to exchange electrical signals.

FIG10 is a schematic diagram of the structure of an optical communication system provided in an embodiment of the present application. As shown in FIG10 , 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.

The first WSS is used to output the first optical signal from the 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 used to output the second optical signal from the 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 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 any optical transmission link, and the first node is a 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 WSS connected to the optical transmission link where the second node is located. 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.

For example, in FIG10 , a circle represents a transmission node. Assume that the first node is transmission node N1 and the second node is transmission node N2. In a first time period, the link between transmission node N1 and transmission node N2 is normal, and the master node sends a first optical signal to the transmission node N2 through a branch port of the first WSS. In a second time period, the link between transmission node N1 and transmission node N2 is disconnected, and the standby node sends a second optical signal to the transmission node N2 through a branch port of the second WSS.

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

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

In an embodiment of the present application, the local device of the master node may include multiple optical transform units (OTUs), each OTU corresponds to a different wavelength, that is, different OTUs are used to send 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 sent by multiple OTUs into one channel to obtain a combined signal, and send the combined signal to the common port COM2 of the first WSS. The structure of the local device of the standby node is similar to that of the local device of the master node, and will not be described in detail here.

The optical communication system further includes a first protection component, which is connected to a local device of the master node and is also connected to a protection port COM3 of the second WSS. The first protection component is used to obtain a first optical signal from a local optical signal sent by the local device, and output a second optical signal to the protection port of the second WSS.

In a possible implementation, the wavelengths of the first optical signal and the second optical signal are the same, that is, the first optical signal and the second optical signal 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, input it into the common port COM3 of the second WSS, and control the second WSS to output the first optical signal received by its common port COM3 from the branch port of the second WSS connected to the optical transmission link where the second node is located.

Illustratively, in this embodiment, the first protection component can adopt any one of the following structures.

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.

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.

Continuing with the example of transmission node N1 as the first node and transmission node N2 as the second node, in the first time period, the optical transmission link is normal, the first WSS outputs the first optical signal among the local optical signals received by its common port COM2 from its branch port P1, and transmits it to the transmission node N2 through the transmission node N1; the second WSS ignores the optical signal received by its common port COM3, that is, the optical signal received by the common port COM3 of the second WSS is not output from any branch port of the second WSS.

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 learns whether the optical transmission link is abnormal, and it can be learned by automatic detection or manual configuration.

The second structure and the first protection component include a first combiner, a second combiner and a plurality of optical switches, and the plurality of optical switches correspond to a plurality of OTUs one by one. The input end of each optical switch is connected to a corresponding OTU, an 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 COM2 of the first WSS, 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 common port COM3 of the second WSS. In this way, the optical switch can be used to select whether to output the corresponding OTU output optical signal to the first WSS or to the second WSS. Among them, the first combiner can be a combiner in the local device of the aforementioned master node.

Let's continue to take transmission node N1 as the first node and transmission node N2 as the second node as an example. In the first time period, the optical transmission link is normal. Each optical switch connects the OTU to the input end of the first combiner, so that 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 outputs the first optical signal of the local optical signal received by its common port COM2 from its branch port P1 and transmits it to the transmission node N2 through the transmission node N1.

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 long OTU conducts the OTU with 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 learns whether the optical transmission link is abnormal, and it can be learned by automatic detection or manual configuration.

This implementation is applicable to the scenario where the optical signal currently outputted from the branch port of the second WSS does not contain an optical signal with the same wavelength as the first optical signal. Since at the same time, an optical signal with the same wavelength can only be outputted from one branch port of the second WSS, even if the optical signal outputted from the first protection component to the protection port (i.e., the common port COM3) of the second WSS contains an optical signal with the same wavelength as the optical signal currently outputted from the branch port of the second WSS, it will not affect the original optical signal.

It should be noted that when there is an optical signal with the same wavelength as the first optical signal in the optical signal currently output from the branch port of the second WSS, if the first optical signal is directly switched to the common port COM3 of the second WSS, it will not be output normally 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 in the optical signal currently output from the branch port of the second WSS.

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

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 is generated based on the information, and the second optical signal is input into the common port COM3 of the second WSS, and the second WSS is controlled to output the second optical signal received by its common port COM3 from the branch port P1 of the second WSS.

In this embodiment, the first protection component may include a spectrometer, a filter, a light source, a modulator, and a processing circuit. The input end of the spectrometer is connected to the output end of the local device, and the output end of the spectrometer is connected to the input end of the filter. The light source is used to output a light beam of a wavelength corresponding to the second optical signal, and the processing circuit is used to convert the light output by the filter into an electrical signal, and control the modulator to modulate the light beam output by the light source based on the electrical signal to obtain the second optical signal.

Optionally, the master node and the standby node may be the same optical switching device, or different optical switching devices. When the master node and the standby node are different optical switching devices, the master node and the standby node may be located in the same geographical location, for example, in the same computer room, or the master node and the standby node may be located in different geographical locations, for example, in different computer rooms.

In some examples, the master node and the standby node are two different ROADMs. The first WSS is a WSS in the branch side of the master node, and the second WSS is a WSS in the branch side of the standby node. A common port COM1 of the first WSS is used to connect to the line side of the ROADM to receive 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.) to receive an optical signal that the local device needs to send to a transmission device or a standby 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 to receive 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.) to receive an optical signal that the local device needs to send to a transmission device or a master node. Another common port COM3 of the second WSS serves as a protection port to receive an optical signal transmitted by the master node.

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

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

Optionally, as shown in FIG10 , the master node further includes a third WSS, and the standby node further includes a fourth WSS. The branch ports of the third WSS correspond to the branch ports of the fourth WSS one by one, and the corresponding branch ports of the third WSS and the fourth WSS are connected with the aforementioned optical transmission link. Since each transmission node needs to send optical signals in addition to receiving optical signals, each transmission node in the optical transmission link can send optical signals to the line side of the master node through the third WSS or the fourth WSS.

Among them, the third WSS is used to receive the third optical signal from the second node from the 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 used to receive the fourth optical signal from the second node from the fourth target branch port of the fourth WSS when the link between the first node and the second node is disconnected. The third optical signal and the fourth optical signal are both used 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.

In some examples, it is assumed that the first node is a transmission node N1 and the second node is a transmission node N2. The link between the transmission node N1 and the transmission node N2 is normal, and the transmission node N2 sends the third optical signal to the master node through a branch port of the third WSS. In the fourth time period, the link between the transmission node N1 and the transmission node N2 is disconnected, and the transmission node N2 sends the fourth optical signal to the backup node through a branch port of the fourth WSS.

Optionally, the first WSS and the third WSS can be integrated together, that is, a Twin WSS. Similarly, the second WSS and the fourth WSS can be integrated together, that is, a Twin WSS.

In the embodiment of the present application, the master node and the standby node are relative. For example, assuming that there are a first switching device and a second switching device, the second switching device can be the standby node of the first switching device, and the first switching device can also be the standby node of the second switching device. That is, the first switching device and the second switching device are mutually master and standby. In this case, the optical communication system also includes a second protection component, which is connected to the local device of the standby 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 standby node, and output the sixth optical signal to the protection port COM3 of the first WSS.

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

During implementation, the first protection component and the second protection component can be integrated into the master node or the backup node; or, a part of the first protection component and the second protection component are integrated into the master node, and the other part of the first protection component and the second protection component are 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.

For example, in FIG. 10 , the first protection component includes a splitter S1, and the first protection component is integrated in the master node; the second protection component includes a splitter S2, and the second protection component is integrated in the standby node.

It should be noted that FIG10 shows only one optical transmission link. In practical applications, the number of optical transmission links can be more, such as 2 or 3, 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 embodiment of the present application does 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 contained in different optical transmission links can be the same or different.

In addition, in Fig. 10, the example of protecting the common port COM2 of the master node for receiving the local optical signal of the master node by the first protection component and protecting the common port COM2 of the standby node for receiving the local optical signal of the standby node by the second protection component is used for explanation. In other embodiments, the common port COM1 of the master node for receiving the line-side optical signal of the master node can also be protected by the first protection component; and/or, the common port COM1 of the standby node for receiving the line-side optical signal of the standby node can be protected by the second protection component.

When the common port COM1 of the master node for receiving the line-side optical signal of the master node is protected by the first protection component, the first protection component is connected to the common port COM1 of the first WSS, and the first protection component 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.

Similarly, when the common port COM1 of the standby node for receiving the line-side optical signal of the standby node is protected by the second protection component, the second protection component is connected to the common port COM1 of the second WSS, and the second protection component is also connected to the protection port COM3 of the first WSS. The second protection component is used 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.

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

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

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

In some further 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, and receiving the first optical signal from a 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.

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

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, similar words such as "one" or "one" do not indicate a quantitative limitation, but rather indicate the existence of at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" 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.

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

Claims (17)

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. 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. 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 any pair of first common ports and any one of the first branch ports is a second distance, and the first distance is not equal to the second distance. 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. 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. 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 the distance between any two of the second common ports is greater than the distance between any two of the second branch ports. 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. 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. The wavelength selective switch according to any one of claims 5 to 8 is 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. 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. An optical communication device, characterized by comprising 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. 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. The optical communication system according to claim 12, characterized in that the wavelengths of the first optical signal and the second optical signal are different. 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. The optical communication system according to claim 14, characterized in that the first protection component comprises an optical splitter, an input end of the optical splitter is connected to an output end of the 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. The optical communication system according to any one of claims 12 to 15, characterized in that the master node further comprises a third wavelength selective switch, the backup node further comprises 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. An optical signal transmission method, characterized in that it is applied to the optical communication system according to any one of claims 12 to 16, and the method comprises: 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.