CN117856884A

CN117856884A - Optical communication system, access node and optical module

Info

Publication number: CN117856884A
Application number: CN202211736177.9A
Authority: CN
Inventors: 孙文惠; 孙晓斌; 高士民; 杨洋; 宋冬锋
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-10-09
Filing date: 2022-12-31
Publication date: 2024-04-09
Also published as: CN117857948A; WO2024078242A1; WO2024078104A1; CN117856885A; CN117856969A; CN117857069A; CN117857949A; CN117856962A

Abstract

The embodiment of the application discloses an optical communication system, an access node and an optical module, wherein the optical communication system comprises a main link and a backup link for backing up the main link, and each intermediate access node included in the optical communication system is respectively connected with the main link and the backup link through the same optical module, so that the complexity and the cost of networking of the optical communication system can be reduced. The optical communication system comprises a main node, a backup node and at least one intermediate access node, wherein the optical communication system further comprises a main link and a backup link, each intermediate access node in the at least one intermediate access node is connected with the main node and the backup node through the main link and the backup link respectively, and the intermediate access node is connected with the main link and the backup link through the same included optical module.

Description

Optical communication system, access node and optical module

The present application claims priority from the chinese patent application filed on 10 months 09 of 2022, filed under the application number 202211226927.8, entitled "P2 MP network system based on F-TDMA and IP and optical depth fusion", the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to the field of optical communications technologies, and in particular, to an optical communications system, an access node, and an optical module.

Background

The networking types of optical communication systems are becoming more and more diversified, and one networking type of an optical communication system is shown in fig. 1, where fig. 1 is a diagram illustrating a structure example of an existing optical communication system. For example, the optical communication system 100 includes a primary core node (CP) and a backup CP. The primary CP is connected to the AP131 and the AP132 in sequence, and the backup CP is connected to the AP131 and the AP132 in sequence. The main link of the optical communication system includes a main CP, a main optical module of the AP131, and a main optical module of the AP132. The backup link of the optical communication system includes a backup CP, a backup optical module of the AP131, and a backup optical module of the AP132.

If the main link fails, for example, an optical fiber link between the main optical module of the AP131 and the main optical module of the AP132 fails, the optical communication system is switched from the main link transmission to the backup link transmission, for example, the uplink service of the AP132 is sequentially transmitted to the backup CP through the backup optical module of the AP132 and the backup optical module of the AP131, so that the uplink service of the AP132 can be normally transmitted to the backup CP through the backup link even if the main link fails.

Therefore, in order to realize the backup with the backup link being the main link, each AP configuration included in the optical communication system needs to be respectively connected to the main optical module of the main link and the backup optical module connected to the backup link, thereby improving the networking complexity and cost of the optical communication system.

Disclosure of Invention

The embodiment of the application provides an optical communication system, an access node and an optical module, wherein the optical communication system comprises a main link and a backup link for backing up the main link, and each intermediate access node included in the optical communication system is respectively connected with the main link and the backup link through the same optical module, so that the complexity and the cost of networking of the optical communication system can be reduced.

The first aspect of the present application provides an optical communication system, where the optical communication system includes a main node, a backup node, and at least one intermediate access node, where the optical communication system further includes a main link and a backup link, each intermediate access node in the at least one intermediate access node is connected to the main node and the backup node through the main link and the backup link, respectively, and the intermediate access node is connected to the main link and the backup link through an included same optical module.

According to the scheme, any intermediate access node can realize communication between the intermediate access node and the main node through the main link and between the intermediate access node and the backup node through the backup link only by using the same optical module, and the communication between the main link and the backup link is realized without using two independent optical modules, so that the number of the optical modules included in the intermediate access node is effectively reduced, the networking complexity of an optical communication system is reduced, and the networking cost of the optical communication system is further reduced.

Based on the first aspect, in an optional implementation manner, the at least one intermediate access node includes a first intermediate access node, the first intermediate access node includes a first optical module, the optical communication system further includes a first branching optical combiner, a first main optical combiner, and a first backup optical combiner, the first optical module is connected to the first branching optical combiner, the first branching optical combiner is further connected to the first main optical combiner and the first backup optical combiner respectively, and the first main optical combiner is connected to the main link, and the first backup optical combiner is connected to the backup link.

By adopting the implementation mode, the first intermediate access node can be effectively ensured, and the first intermediate access node can be connected to the main link and also can be connected to the backup link through the same optical module.

Based on the first aspect, in an optional implementation manner, the first main optical combiner is an optical power adjustable optical combiner, an input port and a first output port of the first main optical combiner are respectively connected with the main link, and a second output port of the first main optical combiner is connected with the first shunt optical combiner; the input port of the first main optical combiner is used for receiving the first main link optical power from the main link, the first main optical combiner is used for tuning the first main link optical power into the second main link optical power and the third main link optical power, the first output port of the first main optical combiner is used for sending the second main link optical power to the main link, the second output port of the first main optical combiner is used for sending the third main link optical power to the first branch optical combiner, and the first branch optical combiner is used for sending the third main link optical power to the first optical module.

By adopting the implementation mode, the first main optical combiner is the optical power adjustable optical combiner, so that the optical power of the first output port and the optical power of the second output port of the first main optical combiner can be dynamically and flexibly adjusted according to the requirement.

Based on the first aspect, in an optional implementation manner, the at least one intermediate access node further includes a second intermediate access node, the second intermediate access node includes a second optical module, and the optical communication system further includes a second splitting optical combiner and a second main optical combiner; and under the condition that the distance between the first intermediate access node and the main node is smaller than the distance between the second intermediate access node and the main node, the light splitting proportion corresponding to the second output port of the first main light combiner is smaller than the light splitting proportion corresponding to the second output port of the second main light combiner.

With the implementation, the distance between the second intermediate access node and the master node is greater than the distance between the first intermediate access node and the master node. Because the light splitting proportion corresponding to the second output port of the first main optical combiner is smaller than the light splitting proportion corresponding to the second output port of the second main optical combiner, the second intermediate access node far away from the main node in the downlink direction can obtain enough downlink optical power, and the number of the intermediate access nodes included in the optical communication system is further improved. In the uplink direction, by tuning the light splitting proportion corresponding to the second output port of each main light combiner, the optical power transmitted to the main link by different intermediate access nodes through the main light combiners is adjusted, so that the uplink optical power received by the main node through the main link is in an balanced state in different time periods, the optical module of the main node for receiving the uplink optical power from the main link does not need to have strong sensitivity, and the gain of the optical module of the main node for processing the uplink optical power from each intermediate access node is effectively reduced.

Based on the first aspect, in an optional implementation manner, the optical power output by the second output port of the first main optical combiner is equal to the optical power output by the second output port of the second main optical combiner.

By adopting the implementation manner, the optical power output at the second output port of the first main optical combiner is equal to the optical power output at the second output port of the second main optical combiner, so that the number of intermediate access nodes included in the optical communication system can be increased as much as possible.

Based on the first aspect, in an optional implementation manner, the first branching optical combiner is an optical combiner with a fixed optical splitting ratio.

By adopting the implementation mode, under the condition that the branching optical combiner is an optical combiner with fixed light splitting proportion, the main link and the backup link of the optical communication system both transmit uplink business. Under the condition that the main link is in normal transmission, the main node can successfully receive uplink service through the main link. The backup node is also able to receive upstream traffic transmitted via the backup link. If the optical communication system is switched from the main link transmission to the backup link transmission, the backup node is always in a state of receiving the uplink service via the backup link, so that the backup node can be in a normal working state rapidly, the switching time delay from the main link to the backup link is reduced, and the packet loss rate of each intermediate access node for sending the uplink service to the backup node is reduced.

Based on the first aspect, in an optional implementation manner, the first shunt optical combiner is an optical power adjustable optical combiner, a main port of the first shunt optical combiner is connected with the first main optical combiner, and a backup port of the first shunt optical combiner is connected with the first backup optical combiner; the first optical splitter is configured to tune optical power of a backup port of the first optical splitter to zero.

By adopting the implementation mode, under the condition that the optical power of the backup port of the first branching optical combiner is tuned to zero, the optical power is prevented from being transmitted to the backup link when the main link is in a normal transmission state, and further the loss of the optical power in the process that the uplink optical power is transmitted to the main node through the main link is reduced.

Based on the first aspect, in an optional implementation manner, if the first optical module is in an abnormal state, the first main optical combiner is configured to tune an optical power of the second output of the first main optical combiner to zero.

By adopting the implementation manner, if the first optical module is in an abnormal state, the optical power of the second output of the first main optical combiner is tuned to zero, so that the interference of uplink service is avoided.

Based on the first aspect, in an optional implementation manner, the first backup optical combiner is an optical power adjustable optical combiner, an input port and a first output port of the first backup optical combiner are respectively connected with the backup link, and a second output port of the first backup optical combiner is connected with the first shunt optical combiner; the input port of the first backup optical combiner is used for receiving the first backup link optical power from the backup link, the first backup optical combiner is used for tuning the first backup link optical power into the second backup link optical power and the third backup link optical power, the first output port of the first backup optical combiner is used for sending the second backup link optical power to the backup link, the second output port of the first backup optical combiner is used for sending the third backup link optical power to the first shunt optical combiner, and the first shunt optical combiner is used for sending the third backup link optical power to the first optical module.

By adopting the implementation mode, under the condition that the transmission of the main link is switched to the backup link, the backup link can successfully realize the communication between each intermediate access node and the backup node, and the successful communication between each intermediate access node and the backup node under the condition that the transmission of the main link is abnormal is ensured.

Based on the first aspect, in an optional implementation manner, the optical communication system includes a plurality of intermediate access nodes connected in sequence, the plurality of intermediate access nodes includes a first intermediate access node and a last intermediate access node, the main link includes a first sub-main link and a second sub-main link, the last intermediate access node is connected with one intermediate access node of the plurality of intermediate access nodes through the first sub-main link, and the last intermediate access node is connected with the main node through the second sub-main link, the backup link includes a first sub-backup link and a second sub-backup link, the first intermediate access node is connected with one intermediate access node of the plurality of intermediate access nodes through the first sub-backup link, and the first intermediate access node is connected with the backup node through the second sub-backup link.

By adopting the implementation mode, the switching to the backup link can be successfully realized under the condition of annular networking and the abnormal condition of main link transmission, and the transmission reliability of the annular networking is ensured.

Based on the first aspect, in an optional implementation manner, if the transmission of the main link is switched to the backup link, the main node is configured to send a first round trip delay time RTD to the backup node, where the first RTD is an RTD that optical power is transmitted between the first intermediate access node and the main node via the main link; the backup node is configured to obtain a second RTD according to the first RTD, where the second RTD is an RTD that optical power is transmitted between the first intermediate access node and the backup node via the backup link; the backup node is further configured to obtain, via the backup link, uplink optical power from the first intermediate access node according to the second RTD.

By adopting the implementation mode, under the condition that the main link transmission is switched to the backup link, the backup node does not need to re-measure the second RTD between the backup node and each intermediate access node, but directly calculates the second RTD according to the first RTD from the main node, thereby improving the switching efficiency of the main link transmission to the backup link and reducing the time delay of service interruption in the switching process.

Based on the first aspect, in an optional implementation manner, the backup node is configured to determine, in a process of obtaining the second RTD according to the first RTD, that a difference between a target RTD and the first RTD is the second RTD, where the target RTD is an RTD that an optical signal is transmitted between the primary node and the backup node sequentially through the plurality of intermediate access nodes.

By adopting the implementation mode, the backup node can successfully calculate the second RTD according to the first RTD, so that the backup node does not need to re-measure the second RTD between the backup node and the AP.

Based on the first aspect, in an optional implementation manner, the primary node is configured to detect that the uplink optical power sent by the primary link is not less than a preset time period and not received from the first intermediate access node, and switch transmission of the primary link to the backup link.

By adopting the implementation mode, the main node can timely and successfully detect that the transmission of the main link is abnormal, so that the transmission of the main link is timely switched to the backup link under the condition that the transmission of the main link is abnormal, and the reliability of the transmission of the optical communication system is improved.

Based on the first aspect, in an optional implementation manner, before the master node is configured to switch transmission of the master link to the backup link, the master node is further configured to detect that uplink optical power sent by the second intermediate access node through the master link is not less than or equal to the preset time period, where a distance between the first intermediate access node and the master node is less than a distance between the second intermediate access node and the master node.

By adopting the implementation mode, the accuracy of detecting the occurrence of the abnormality of the main link transmission by the main node can be improved.

Based on the first aspect, in an optional implementation manner, the optical power adjustable optical splitter includes an electrode and an optical waveguide component connected with the electrode; the optical waveguide assembly includes an input port for receiving optical power, a first output port, and a second output port, the electrode for transmitting a target voltage to the optical waveguide assembly, the target voltage for tuning the optical power of the first output port and the optical power of the second output port.

By adopting the implementation mode, the optical power of each output port of the optical power adjustable optical combiner can be tuned in an electric control mode, and under the condition that the optical communication system comprises a plurality of optical power adjustable optical combiners, the difficulty of tuning the optical power of each output port of each optical power adjustable optical combiners is effectively reduced, and the efficiency of tuning the optical power of each output port is improved.

The second aspect of the present application provides an access node, the access node includes an optical module, a branching optical multiplexer, a main optical multiplexer and a backup optical multiplexer, the optical module is connected with the branching optical multiplexer, the branching optical multiplexer is further connected with the main optical multiplexer and the backup optical multiplexer respectively, the main optical multiplexer is used for connecting a main link, the backup optical multiplexer is used for connecting a backup link, the main link is used for connecting the optical module and the main node, and the backup link is used for connecting the optical module and the backup node.

For an explanation of the beneficial effects of this aspect, please refer to the first aspect, and detailed descriptions thereof are omitted.

Based on the second aspect, in an optional implementation manner, the main optical combiner and the backup optical combiner are optical power adjustable optical combiners.

Based on the second aspect, in an optional implementation manner, the branching optical combiner is a fixed optical splitting ratio optical combiner or an optical power adjustable optical combiner.

The third aspect of the application provides an optical module, the optical module includes laser instrument, diode, branching optical multiplexer, main optical multiplexer and backup optical multiplexer, the laser instrument with the diode respectively with branching optical multiplexer is connected, branching optical multiplexer still respectively with main optical multiplexer and backup optical multiplexer are connected, main optical multiplexer is used for connecting the main link, backup optical multiplexer is used for connecting the backup link, the main link is used for connecting optical module and main node, backup link is used for connecting optical module and backup node.

Based on the third aspect, in an optional implementation manner, the main optical combiner and the backup optical combiner are optical power adjustable optical combiners.

Based on the third aspect, in an optional implementation manner, the branching optical combiner is a fixed optical splitting ratio optical combiner or an optical power adjustable optical combiner.

Drawings

Fig. 1 is a diagram showing an example of the structure of a conventional optical communication system;

fig. 2 is a structural example diagram of an optical communication system provided in the present application;

fig. 3 is a structural example diagram of an embodiment of the first AP;

fig. 4 is an optical power spectrum exemplary diagram of an optical communication system for transmitting downlink traffic provided in the present application;

fig. 5 is a diagram of an optical combination example of optical power of an optical communication system for transmitting uplink traffic provided in the present application;

fig. 6 is another optical combination example diagram of optical power of an optical communication system for transmitting uplink traffic provided in the present application;

fig. 7 is a diagram of another optical combination example of optical power of an optical communication system for transmitting uplink traffic provided in the present application;

fig. 8 is a structural example diagram of another embodiment of an optical communication system provided in the present application;

fig. 9 is a structural example diagram of another embodiment of an optical communication system provided in the present application;

fig. 10 is an exemplary graph of round trip delay time of an optical communication system provided herein;

FIG. 11 is a diagram showing an overall structure of an optical power tunable optical combiner according to an embodiment of the present disclosure;

FIG. 12 is a top view of the optical power tunable optical splitter of FIG. 11;

FIG. 13 is a schematic diagram showing an example of a cross-sectional structure of the optical power tunable optical splitter shown in FIG. 11;

Fig. 14 is a structural example diagram of another embodiment of an optical communication system provided in the present application;

FIG. 15 is a diagram showing an example of the structure of a main optical combiner according to an embodiment of the present application;

fig. 16 is a structural example diagram of an AP provided in the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In order to improve the reliability of the optical communication system, the optical communication system provided by the application comprises a main link and a backup link for backing up the main link, and the backup link can take over the transmission of the main link under the condition that the transmission of the main link is abnormal so as to ensure the normal transmission of the optical communication system.

First, referring to fig. 2, a structure of an optical communication system provided in the present application will be described, where fig. 2 is a structural example diagram of an optical communication system provided in the present application. Fig. 2 illustrates an example of a chain-type networking of an optical communication system.

The optical communication system 200 includes a master node, a backup node, a plurality of intermediate nodes sequentially connected to the master node, and a plurality of intermediate nodes sequentially connected to the backup node. In this embodiment, the master node is taken as a master CP210, the backup node is taken as a backup CP220, and the intermediate node is taken as an AP as an example. Fig. 2 illustrates an optical communication system 200 including three APs, namely a first AP230, a second AP240, and a third AP 250. The first AP230 is connected to the primary CP210 and the backup CP220, respectively. The primary CP210, the first AP230, the second AP240, and the third AP250 are sequentially connected, and the backup CP220, the first AP230, the second AP240, and the third AP250 are sequentially connected. The number of APs included in the optical communication system 200 is not limited in this embodiment. To ensure reliability of the optical communication system 200, the optical communication system 200 further includes a main link 261 and a backup link 262 for backing up the main link 261.

The network to which the optical communication system 200 is applied in this embodiment is not limited, for example, if the optical communication system 200 shown in this embodiment is applied to a passive optical network (passive optical network, PON), the CP may be an optical line terminal OLT, and the AP may be an optical network unit (optical network unit, ONU) or an optical network terminal (optical network terminal, ONT). If the optical communication system 200 is applied to an optical transport network (optical transport network, OTN), then both the CP and the AP may be OTN devices.

Taking the first AP230 as an example, the structure of each AP included in the optical communication system 200 will be described. The first AP230 includes a first AP-side device 231, a first optical module 232, a first shunt optical combiner 233, a first main optical combiner 234, and a first backup optical combiner 235. Wherein the first AP-side device 231 may be a switch (e.g., core layer switch, layer 2 switch), a router, or the like. The first optical module 232 may be directly inserted into the first AP-side device 231, or may be integrated with the first AP-side device 231. The first AP-side device 231, the first optical module 232, and the first optical splitter multiplexer 233 are sequentially connected, the first optical splitter multiplexer 233 is further connected to the first main optical splitter 234 and the first backup optical splitter 235, the first main optical splitter 234 is further connected to the main link 261, and the first backup optical splitter 235 is further connected to the backup link 262. The second AP240 includes a second AP side device 241, a second optical module 242, a second optical splitter 243, a second main optical splitter 244, and a second backup optical splitter 245, and for the description of specific connection relationships, please refer to the description of the first AP230, and details are not repeated. For a description of other AP structures included in the optical communication system, please refer to the description of the first AP230, which is not repeated.

In the example of the optical communication system 200 shown in fig. 2, the main link 261 specifically includes an optical fiber connected between the optical module of the main CP210 and the first main optical combiner 234, an optical fiber connected between the first main optical combiner 234 and the second main optical combiner 244, and an optical fiber connected between the second main optical combiner 244 and the third main optical combiner of the third AP 250. The backup link 262 includes an optical fiber connected between the optical module of the backup CP220 and the first backup optical splitter 235, an optical fiber connected between the first backup optical splitter 235 and the second backup optical splitter 245, and an optical fiber connected between the second backup optical splitter 245 and the third optical splitter of the third AP 250. And each AP included in the optical communication system 200 can be connected to the main link 261 through the main optical combiner included in the AP, and to the main CP210 through the main link 261. For example, the first AP230 is connected to the main link 261 through a first main optical combiner 234 included in the first AP 230. Each AP included in the optical fiber communication system 200 can be connected to the backup link 262 through the backup optical combiner included in the AP, and to the backup CP220 through the backup link 262. For example, the first AP230 is connected to the backup link 262 through a first backup optical combiner 235 included in the first AP 230.

As can be seen from the description of the structure of the first AP230, the first optical module 232 included in the first AP230 is connected to the main link 261 through the first branching optical combiner 233 and the first main optical combiner 234, and similarly, the first optical module 232 is connected to the backup link 262 through the first branching optical combiner 233 and the first backup optical combiner 235. It is understood that the main link 261 and the backup link 262 are connected with the same optical module in the same AP. That is, the optical communication system 200 according to the present embodiment can realize connection between the same optical module in the AP and the main link 261 and the backup link 262, respectively.

Taking the communication of the second AP240 as an example, if the main link 261 is in a normal transmission state, uplink traffic from the second optical module 242 of the second AP240 is transmitted to the main CP210 via the main link 261 as shown above. Downstream traffic from the primary CP, and which needs to be sent to the second AP240, is transmitted to the second optical module 242 via the primary link 261. If an abnormal state occurs in the main link, and uplink traffic of at least one AP included in the optical communication system 200 cannot be transmitted to the main CP210 through the main link 261, the transmission of the main link 261 may be switched to the backup link 262. In case of switching to the backup link 262, the uplink traffic of the second optical module 242 of the second AP240 is transmitted to the backup CP220 via the backup link 262 as shown above. Downstream traffic from the backup CP220 that needs to be sent to the second AP240 is transmitted to the second optical module 242 via the backup link 262.

It can be seen that, no matter the second AP of the optical communication system 200 communicates through the main link 261 or communicates through the backup link 262, the second AP can be implemented only by one second optical module 242, and two independent optical modules are not required to be configured for the main link 261 and the backup link 262 respectively, so that the number of optical modules included in the AP is effectively reduced, the networking complexity of the optical communication system is reduced, and the networking cost of the optical communication system is further reduced.

The implementation of the AP communicating with the primary CP210 via the primary link 261 is described below:

fig. 2 and fig. 3 are combined, where fig. 3 is a structural example diagram of an embodiment of the first AP. The first AP230 in this embodiment includes a first main optical combiner 234 that is an optical power tunable optical combiner. The first main optical combiner 234 includes an input port 301, a first output port 302, and a second output port 303. The first main optical combiner 234 is capable of dynamically and flexibly tuning (tuning) the split ratio corresponding to the first output port 302 and the split ratio corresponding to the second output port 303.

Wherein the second output port 303 of the first main optical combiner 234 is connected to the first split optical combiner 233. The first output port 302 is connected to the optical fiber between the second AP240 and the first main optical combiner 234. And the input port 301 is connected to the optical fiber between the first main optical combiner 234 and the main CP 210. A process in which the primary CP210 transmits downlink traffic to the first AP230 and the second AP240 is described with reference to fig. 2 to 4, where fig. 4 is an optical power spectrum example diagram of the optical communication system provided in the present application for transmitting the downlink traffic. The primary CP210 transmits a downlink optical signal to the first primary optical combiner 234 via a primary link connected between the first primary optical combiner 234 and the primary CP210, the optical power of the downlink optical signal being the first primary link downlink optical power and the downlink optical signal having carried downlink traffic transmitted by the primary CP to the first AP230 and the second AP240. The input port 301 of the first main optical combiner 234 is configured to receive a first main link downlink optical power from the main link. The first main optical combiner 234 tunes the first main downlink optical power to the second main downlink optical power and the third main downlink optical power according to the optical splitting ratio corresponding to the first output port 302 and the optical splitting ratio corresponding to the second output port 303, and the first output port 302 of the first main optical combiner 234 is configured to send the second main downlink optical power to the main link, and the second main downlink optical power transmitted via the main link can be successfully sent to the second AP240. The second AP240 can obtain the downlink traffic from the CP210 from the second main link downlink optical power, and the process of the second AP processing the second main link downlink optical power is referred to as the process of the first AP230 processing the first main link downlink optical power in this embodiment, which is not described in detail. The second output port 303 of the first main optical combiner 234 is configured to send the third main link downlink optical power to the first split optical combiner 233. The first optical splitter/combiner 233 can send the third main link downlink optical power to the first optical module 232, so that the first optical module 232 can obtain the downlink traffic from the main CP210 from the third main link downlink optical power.

The following describes advantages of implementing downlink service transmission by using an optical power adjustable optical combiner for the main optical combiner of each AP shown in this embodiment:

in the case that the optical communication system is of a ring-type networking, the optical communication system and the master CP are sequentially connected to a plurality of APs, and the downlink optical power sent by the master CP is split into a part of optical power after passing through one AP, for example, as shown in fig. 4, the downlink optical power of the first main link output by the master CP210 is split into the downlink optical power of the third main link, which is sent to the first AP230, and the remaining downlink optical power of the second main link is sent to the second AP240. If the first main optical splitter of the first AP230 is an optical splitter with a fixed optical splitting ratio, the further away from the main CP210, the lower the downlink optical power that can be obtained by the AP will be. In order to ensure normal transmission of downlink service between the main CP and the AP, the downlink optical power received by the AP cannot be too low, and the laser included in the AP cannot be successfully detected due to the too low optical power, so that photoelectric conversion cannot be successfully performed, and the number of APs included in the optical communication system is limited.

In the case that the main optical combiner of each AP is an optical power adjustable optical combiner, the downlink optical power that can be obtained by the AP farther from the main CP210 can be effectively improved, so as to further improve the number of APs included in the optical communication system. Specifically, in the case where the optical communication system shown in the present embodiment includes a plurality of APs, the split ratio of the main optical splitter included in each AP may be different. For example, the split ratio of the second output port of the main optical splitter included in the AP is in positive correlation with the distance between the AP and the main CP 210. That is, as the AP is closer to the master CP210, the split ratio of the second output port of the master optical combiner of the AP is smaller, so as to ensure that the AP closer to the master CP can split less optical power from the master CP. Similarly, if the AP is further from the primary CP210, the splitting ratio of the second output port of the primary optical combiner of the AP is greater, so as to ensure that the AP further from the primary CP can split enough optical power from the primary CP, so as to ensure that the AP can normally communicate with the primary CP. As shown in fig. 2, the distance between the first AP230 and the master CP210 is smaller than the distance between the second AP240 and the master CP210, and thus the split ratio of the second output port of the first master optical splitter 234 of the first AP230 is smaller than the split ratio of the second output port of the second master optical splitter 244 of the second AP240. Under the condition that the light splitting ratio of the second output port of the main light splitter included in the AP and the distance between the AP and the main CP210 are in positive correlation, the optical module of the AP far away from the main CP210 is ensured to receive enough optical power, so that even the AP far away from the main CP210 can normally communicate with the main CP, and the quantity of the APs connected by the optical communication system is improved. The optical power output by the second output port of the main optical combiner of each AP in this embodiment may be equal, so as to increase the number of APs sequentially connected to the main CP as much as possible, that is, the optical power output by the second output port of the first main optical combiner 234 of the first AP230 shown in fig. 2 is equal to the optical power output by the second output port of the second main optical combiner 244 of the second AP240.

If the first AP230 and the second AP240 need to send uplink traffic to the primary CP210, the types of the branching optical splitters included in the APs will be different. For example, the AP may include a fixed ratio optical splitter. Specifically, taking the first AP230 shown in fig. 3 as an example, the first optical splitter/combiner 233 includes an input port 313, a primary port 311, and a backup port 312. The input port 313 of the first branching optical combiner 233 is connected to the first optical module 232, the main port 311 of the first branching optical combiner 233 is connected to the second output port 303 of the first main optical combiner 234, and the backup port 312 of the first branching optical combiner 233 is connected to the first backup optical combiner 235. The first optical splitter 233 is a fixed-ratio optical splitter, that is, the optical splitting ratio corresponding to the main port 311 and the optical splitting ratio corresponding to the backup port 312 of the first optical splitter 233 are fixed, for example, the first optical splitter 233 is an equal-ratio optical splitter, and then the optical splitting ratio corresponding to the main port 311 is 50% and the optical splitting ratio corresponding to the backup port 312 is 50%. The present embodiment does not limit the splitting ratio of the first splitter/combiner 233. For a description of the structure of the optical splitter and combiner included in other APs included in the optical communication system provided in the present application, please refer to the description of the first optical splitter and combiner in this embodiment, and detailed description is omitted.

Referring to fig. 2, fig. 3, and fig. 5, which are schematic diagrams of an optical combination example of optical power of an optical communication system for transmitting uplink traffic provided in the present application, in a case where the optical splitter is a fixed-ratio optical splitter, the AP transmits uplink traffic to the primary CP. The second optical module 242 of the second AP240 needs to send a first uplink optical signal to the second optical splitter/combiner 243, where the first uplink optical signal is used to carry uplink traffic that the second AP240 needs to send to the primary CP210, and the optical power of the first uplink optical signal is the first primary link uplink optical power. The second optical splitter 243 is configured to split the first main link uplink optical power to obtain the second main link uplink optical power and the first backup link uplink optical power. Since the second optical splitter 243 is an equal ratio optical splitter, the second main link uplink optical power and the first backup link uplink optical power are equal. The second optical splitter 243 transmits the second main link uplink optical power to the second main optical splitter 244, so that the second main link uplink optical power is transmitted to the first AP230 via the main link, and the second optical splitter 243 transmits the first backup link uplink optical power to the second backup optical splitter 245, so that the first backup link uplink optical power is transmitted to the first AP230 via the backup link.

The first optical module 232 of the first AP230 sends a second uplink optical signal to the first optical splitter/combiner 233, where the second uplink optical signal is used to carry uplink traffic that needs to be sent to the primary CP210 by the first AP230, and the optical power of the second uplink optical signal is the optical power of the third primary link uplink. The first optical splitter/combiner 233 is configured to split the uplink optical power of the third main link to obtain the uplink optical power of the fourth main link and the uplink optical power of the second backup link, and because the first optical splitter/combiner 233 is an equal ratio optical splitter, the uplink optical power of the fourth main link and the uplink optical power of the second backup link are equal. The first optical splitter 233 sends the fourth main link uplink optical power to the first optical splitter 234, and it can be understood that the first optical splitter 234 receives two optical powers, one is the second main link uplink optical power from the second AP240, and the other is the fourth main link uplink optical power from the first optical splitter 233, so that the first optical splitter 234 combines the second main link uplink optical power and the fourth main link uplink optical power to obtain the fifth main link uplink optical power. The first primary optical combiner 234 transmits the fifth primary link uplink optical power to the primary CP210 through the primary link, thereby enabling the primary CP210 to obtain uplink traffic from the second AP240 as well as the first AP 230. The first backup optical combiner 235 receives two optical powers, one being the first backup link uplink optical power from the second AP240 and the other being the second backup link uplink optical power from the first splitter optical combiner 233, and then the first backup optical combiner 235 combines the first backup link uplink optical power and the second backup link uplink optical power to obtain the third backup link uplink optical power. The first backup optical combiner 235 transmits the third backup link uplink optical power to the backup CP220 through the backup link.

When the branching optical splitter included in each AP is an optical splitter with a fixed splitting ratio, both the main link and the backup link of the optical communication system transmit uplink optical power. In the case where the main link is in normal transmission, the main CP210 can successfully receive the uplink optical power via the main link. The backup CP220 is also able to receive the upstream optical signals transmitted via the backup link. If the optical communication system is switched from the main link transmission to the backup link transmission, because the backup CP220 is always in a state of receiving the uplink optical power via the backup link, the backup CP220 can be in a normal working state rapidly, so that the switching delay from the main link to the backup link is reduced, and the packet loss rate of each AP transmitting the uplink service to the CP side is reduced.

Based on the above-described process of sending uplink optical power to the primary CP and the backup CP by each AP, the following describes the advantages of implementing uplink traffic transmission by using an optical power adjustable optical combiner for the primary optical combiner of each AP shown in this embodiment:

if the uplink optical power transmitted from each AP included in the optical communication system to the primary CP fluctuates greatly, the optical module of the primary CP210 needs to increase the sensitivity of processing the uplink optical power, which results in a very large gain of the optical module. The first optical combiner of each AP shown in this embodiment is an optical power adjustable optical combiner, so that the optical power of different APs transmitted to the main link via the main optical combiner can be adjusted by tuning the optical splitting ratio corresponding to the second output port of each main optical combiner, so that the uplink optical power received by the main CP210 via the main link is in an balanced state in different time periods, the optical module of the main CP210 for receiving the uplink optical power from the main link does not need to have strong sensitivity, and the gain of the optical module of the CP for processing the uplink optical power from each AP is effectively reduced.

The optical splitter/combiner included in each AP shown in this embodiment may be an optical power adjustable optical splitter. Then, a procedure of transmitting uplink traffic to the primary CP by the AP is described with reference to fig. 6, where fig. 6 is another optical combination exemplary diagram of optical power of the optical communication system for transmitting uplink traffic provided in the present application.

The second optical module 242 of the second AP needs to send a first uplink optical signal to the second optical splitter/combiner 243, where the first uplink optical signal is used to carry uplink traffic that the second AP240 needs to send to the primary CP210, and the optical power of the first uplink optical signal is the uplink optical power of the first primary link. Since the second optical splitter 243 is an optical power adjustable optical splitter, the optical power of the backup port of the second optical splitter 243 is tuned to zero, and the second optical splitter 243 does not transmit optical power to the second backup optical splitter 245, so that the first main link uplink optical power from the second optical module 242 can be transmitted to the second main optical splitter 244 without being split, and as shown in fig. 6, the uplink optical power transmitted to the main CP by the optical module via the main link is improved compared to the example shown in fig. 5. Similarly, the first optical splitter/combiner 233 of the first AP230 is also an optical power adjustable optical splitter, and the optical power of the backup port of the optical power adjustable optical splitter is tuned to zero, so that the third main link uplink optical power sent by the first optical module 232 can be transmitted to the main link without being split by the first optical splitter/combiner 233. The main optical splitter of each AP sends uplink optical power to the main CP210 via the main link, as shown in fig. 5, which is not described in detail. By adopting the branching optical combiner, the optical power can be prevented from being transmitted to the backup link, so that the loss of the optical power in the process that the uplink optical power is transmitted to the main CP through the main link is reduced.

The main link shown in the optical communication system in this embodiment can also ensure that, in the case that any AP fails, communication between the main link and the main CP by other APs in a normal transmission state is not affected.

Referring to fig. 1, in the existing optical communication system, if the main optical module of the AP131 fails, the uplink optical power of the AP132 cannot be successfully transmitted to the main CP through the main link via forwarding of the AP 131. That is, in the existing optical communication system, if an AP fails, the downstream AP that fails cannot transmit uplink optical power to the primary CP via the primary link. In the optical communication system shown in this embodiment, when the AP fails, the downstream AP that does not fail will not be affected to transmit the uplink optical power to the primary CP via the primary link. Fig. 2, fig. 3, and fig. 7 are specific combinations, where fig. 7 is a diagram of another optical combination example of optical power of an optical communication system for transmitting uplink traffic provided in the present application. If the first optical module 232 of the first AP230 fails, the first optical module 232 cannot communicate with the primary CP 210. For example, the primary CP210 may allocate a target period of time to the first optical module 232 of the first AP230 in advance, and then the first optical module 232 may transmit uplink optical power to the primary link during the target period of time. If the time period for the first optical module 232 to transmit the uplink optical power to the main link is different from the target time period, the uplink optical power transmitted by the first optical module 232 to the main link may cause interference to the uplink optical power transmitted by other APs to the main link. In order to avoid that the abnormal first optical module 232 does not cause interference to other APs, the AP side device of the first AP230 tunes the optical power of the second output port of the first main optical combiner 234 to zero, so that the third main uplink optical power sent by the first optical module 232 cannot be transmitted to the main link through the second output port of the first main optical combiner 234. But the second AP240 is in a normal operating state. Then, in the upstream direction, the second optical module 242 sends the second main link upstream optical power to the second main optical combiner 244, and the second main optical combiner 244 sends the second main link upstream optical power to the first main optical combiner 234 via the main link (see the description shown in fig. 5). While the optical power of the second output port 303 of the first main optical combiner 234 is tuned to zero, the first main optical combiner 234 does not receive the third main link uplink optical power from the first optical module 232, but can only receive the second main link uplink optical power from the second main optical combiner 244, and the first main optical combiner 234 transmits the second main link uplink optical power from the second AP240 to the main CP210 via the main link. It will be appreciated that in case of a failure of the first AP, the first AP can also guarantee that the uplink optical power from the downstream second AP can be successfully transmitted to the primary CP through the primary link. In the downstream direction, if the primary CP210 has determined that the first optical module 232 of the first AP230 has failed, the downstream traffic transmitted by the primary CP210 does not include the downstream traffic transmitted to the first AP, and since the optical power of the second output port 303 of the first primary optical combiner 234 is tuned to zero, the first primary optical combiner 234 does not split the downstream optical power from the primary CP210, but transmits to the second AP240 via the primary link.

In this embodiment, if the main link fails, and the main link cannot normally transmit optical power, for example, the optical fiber connected between the main CP210 and the first AP230 included in the main link shown in fig. 2 breaks, the transmission of the optical communication system is switched from the main link to the backup link. Specifically, referring to the example shown in fig. 2, if the primary CP210 detects that the uplink optical power transmitted via the primary link from the target AP, which is any AP included in the optical communication system, is not received within the preset period of time, the primary CP210 determines that the primary link fails. The duration of the preset time period is not limited in this embodiment, and may be dynamically set according to a specific scenario in which the optical communication system is applied. For example, if the target AP is the second AP240, if the primary CP210 detects that the uplink optical power from the second AP240 is not received via the primary link for not less than the preset period, it is determined that the primary link fails, and to ensure normal communication of the optical communication system, the primary CP210 may switch transmission of the primary link to the backup link. For example, the primary CP210 and the backup CP220 shown in the present embodiment are connected, the primary CP210 may send a handover indication message to the backup CP220, where the handover indication message is used to instruct the backup CP to communicate with each AP through the backup link. That is, the backup CP220 transmits the downstream traffic to each AP via the backup link. Each AP transmits uplink traffic to the backup CP220 via the backup link. For a description of the communication between the backup CP220 and each AP, please refer to the description of the communication between the master CP210 and each AP shown in the above embodiment, which is not described in detail. In order to improve the accuracy of determining whether the main link is failed by the main CP210, if the main CP210 detects that the uplink optical power transmitted through the main link from the target AP is not less than a preset period of time, and also detects that the uplink optical power transmitted through the main link from the downstream target AP is not less than the preset period of time, the distance between the downstream target AP and the main CP210 is greater than the distance between the target AP and the main CP 210. For example, if the target AP is the second AP240, then the downstream target AP is the third AP250. It can be understood that if the primary CP210 detects not less than the preset period of time, it determines that the primary link fails in the case that the uplink optical power from the second AP240 is not received via the primary link, and the uplink optical power from the third AP250 is not detected. Optionally, in other examples, the primary CP210 may also send a handover indication message to the network management device, and then the network management device forwards the handover indication message to the backup CP 220.

In the case where the networking type of the optical communication system is a chain networking and the Round Trip Delay (RTD) between any AP and the primary CP210 is equal to the RTD between the AP and the backup CP220, the primary CP210 sends a handover indication message to the backup CP220, carrying the RTD between each AP and the primary CP 210. For example, the handover indication message carries an RTD between the first AP230 and the primary CP210, an RTD between the second AP240 and the primary CP210, and an RTD between the third AP250 and the backup CP. In a state where transmission of the main link is normal, the main CP may measure RTD with each AP, and each AP transmits uplink traffic to the main CP210 by using a time division multiple access (time division multiple access, TDMA) method. Then, the primary CP210 allocates uplink slots to the APs according to RTDs between the APs and the primary CP, so that the APs can transmit uplink traffic in the slots allocated by the primary CP210, so as to avoid collision and interference between uplink traffic from different APs. Taking the first AP230 as an example, when the master CP210 determines that the transmission of the master link needs to be switched to the backup link, the master CP210 sends the RTD between the master CP210 and the first AP to the backup CP220, and since the RTD between the master CP210 and the first AP is equal to the RTD between the backup CP and the first AP, when the transmission of the master link is switched to the backup link, the backup CP220 does not need to re-measure the RTD between each AP and the backup CP220, and the backup CP220 can directly receive the uplink traffic from each AP according to the RTD from the master CP 210.

In the above embodiment, the optical communication system is used as an example of a chain-type networking, and the networking type of the optical communication system shown in this embodiment may also be a ring-type networking. Referring specifically to fig. 8, fig. 8 is a schematic diagram of another embodiment of an optical communication system provided in the present application. The optical communication system with the ring network includes a plurality of APs connected in turn, and the number of APs included in the optical communication system is not limited in this embodiment, as in the example shown in fig. 8, and the optical communication system includes four APs as an example. Among the four sequentially connected APs, including the first AP803 connected at the head and the last AP804 connected at the tail, the other two APs (i.e., AP805 and AP 806) are sequentially connected between the first AP803 and the last AP 804. In this embodiment, the AP804 may be referred to as a first AP, and the AP803 may be referred to as a last AP, which is not specifically limited, as long as the first AP and the last AP are connected to two ends of a plurality of sequentially connected APs included in the optical communication system. The optical communication system shown in this embodiment further includes a primary CP801 and a backup CP802, and for the description of the primary CP801 and the backup CP802, please refer to the above embodiment, and details are not repeated. The primary CP801 is also connected to a backup CP. In order to implement ring networking, the four APs shown in this embodiment are respectively connected to the primary CP801 through primary links, and for illustration of specific connection, please refer to fig. 2 and fig. 3, details are not repeated. The ring network shown in fig. 8 is different from the chain network shown in fig. 2 and fig. 3 in that the connection structure of the last AP804 is specifically described with reference to fig. 9, where fig. 9 is a structural example diagram of another embodiment of the optical communication system provided in the present application. Fig. 9 illustrates the connection structure of the last AP804 in the ring network. The last AP804 includes an AP-side device 915, an optical module 914, a branching optical combiner 912, a backup optical combiner 913, and a main optical combiner 911, which are shown in fig. 2 and 3, and are not described in detail. The main link shown in this embodiment further comprises a first sub-main link 901 and a second sub-main link 902. The first sub-main link 901 is an optical fiber connected between the AP806 and the last AP804, and specifically, the first sub-main link 901 is connected between the AP806 and an input port of the main optical combiner 911 of the last AP 804. And a second sub-main link 902 is an optical fiber connected between the last AP804 and the main CP801, and in particular, the second sub-main link 902 is connected between the main CP801 and the first output port of the main optical combiner 911 of the last AP 804. In order to form a ring network, the first AP803 is connected to the AP805 through a first sub-backup link included in the backup link, and the first AP803 is connected to the backup CP802 through a second sub-backup link included in the backup link, for a specific connection manner, please refer to a description of a connection between the last AP804 and the main CP801, which is not described in detail. In this embodiment, for the description of each AP, the primary CP801, and the backup CP802 structure included in the ring network, and the process of communication between the primary CP801 and each AP, please refer to the above embodiment, and details are not repeated.

In the ring networking shown in this embodiment, the description of switching the transmission of the main link to the backup link is referred to in the above-mentioned chain networking, and detailed description is omitted. In the ring networking, if the transmission of the primary link is switched to the backup link, the primary CP801 sends a switching indication message to the backup node, where the switching indication message shown in this embodiment includes a first RTD corresponding to each AP, as shown in table 1:

TABLE 1

Taking AP805 as an example, the first RTD of AP805 is an RTD where optical power is transmitted between AP805 and master CP801 via the master link. It can be appreciated that in case the backup CP802 receives the handover indication message as shown in table 1, the backup CP can obtain the RTD between any AP included in the ring network and the primary CP.

The backup CP8021 can directly obtain the slot indication message shown in table 2 from the handover indication message shown in table 1:

TABLE 2

Identification of AP nodes	Corresponding second RTD
		AP803	The second RTD is RTD-b1
AP805	The second RTD is RTD-b2
		AP806	The second RTD is RTD-b3
AP804	The second RTD is RTD-b4

Referring to fig. 10, fig. 10 is an exemplary diagram of round trip delay time of an optical communication system provided in the present application. Taking the AP805 as an example, the backup CP802 calculates a second RTD corresponding to the AP805 according to the following formula 1, where the second RTD corresponding to the AP805 is an RTD whose optical power is transmitted between the AP805 and the backup CP802 via the backup link.

Equation 1: RTD-b2=target RTD-a2

The target RTD is an RTD in which optical power is transmitted between the primary CP801 and the backup CP802 sequentially via a plurality of APs included in the ring network. It will be appreciated that the target RTD shown in this example is an RTD in which an optical signal is transmitted between the primary CP801 and the backup CP802 via the first AP803, the AP805, the AP806, and the AP804 in this order.

In this embodiment, the RTD between the primary CP801 and the last AP804 and the RTD between the backup CP802 and the first AP803 are the same. For example, the main link and the backup link are different optical fibers in the same optical cable, and for example, the main link and the backup link are different modes in the same optical fiber, which is not limited in this embodiment. In the case where the RTD between the master CP801 and the last AP804 and the RTD between the backup CP802 and the first AP803 are the same, the accuracy of the second RTD corresponding to each AP obtained by the backup CP802 can be ensured. In the case that the backup CP obtains the second RTD corresponding to each AP, the backup CP can communicate with each AP based on the second RTD, and the detailed description is shown in the above embodiment, which is not repeated. It can be understood that under the condition that the main link transmission is switched to the backup link, the backup CP does not need to re-measure the RTD between the backup CP and each AP, but directly calculates the RTD between the backup CP and each AP according to the switching indication message from the main CP, so that the switching efficiency of the main link transmission to the backup link is improved, and the time delay of service interruption in the switching process is reduced.

As can be seen from the foregoing embodiments, the optical power adjustable optical combiner included in each AP can dynamically adjust the optical power of each output port, for example, the main optical combiner shown in the foregoing embodiments is an optical power adjustable optical combiner, and for another example, the branching optical combiner is an optical power adjustable optical combiner, and for another example, the backup optical combiner is an optical power adjustable optical combiner. The following describes the structure of the optical power tunable optical combiner with reference to fig. 11 to 13, where fig. 11 is an overall structure example diagram of an embodiment of the optical power tunable optical combiner provided in the present application, fig. 12 is a top view structure example diagram of the optical power tunable optical combiner shown in fig. 11, and fig. 13 is a cross-sectional structure example diagram of the optical power tunable optical combiner shown in fig. 11. The cross-sectional view shown in fig. 13 is a cross-sectional image obtained by cutting the optical power tunable optical combiner 1100 shown in fig. 11 through the cut surface 1200. And the optical signal transmitted by the first optical waveguide arm 1201 and the optical signal transmitted by the second optical waveguide arm 1202 are perpendicular to the cut plane 1200.

The optical power tunable optical combiner 1100 includes a substrate 1101 and an optical waveguide layer 1102 grown on a surface of the substrate 1101. In this embodiment, lithium niobate is taken as an example of a material constituting the optical waveguide layer 1102, and in other examples, the optical waveguide layer 1102 may be constituted by silicon (Si), silicon nitride (Si 3N 4), ammonium dihydrogen phosphate (NH 4H2PO 4), or a crystal of an button file. An electrode 1103 is grown on the surface of the optical waveguide layer 1102. The electrode 1103 shown in the present embodiment is made of any conductive metal, for example, the electrode 1103 is made of metallic copper (Au) or metallic aluminum (Al) or the like. The substrate 1101 shown in this embodiment may be also referred to as a substrate, a dielectric layer, or the like, and is not particularly limited. The optical waveguide layer 1102 forms an optical waveguide assembly by an etching process or the like, and the electrode 1103 is connected to the optical waveguide assembly. The optical waveguide assembly specifically includes an input port 1111, a first output port 1112, and a second output port 1113. The input port 1111 is configured to receive optical power, and the electrode 1103 is configured to send a target voltage to the optical waveguide assembly, the target voltage being configured to tune the optical power of the first output port 1112 and the optical power of the second output port 1113.

The optical power tunable optical combiner shown in this embodiment is an active optical combiner, and the electrode 1103 can achieve the purpose of tuning the optical power of the first output port 1112 and the optical power of the second output port 1113 by changing the voltage value of the target voltage sent to the optical waveguide assembly. For example, as shown in fig. 2, the main optical combiner included in each AP may be capable of tuning the optical splitting ratio of the second output port of the main optical combiner according to the distance between the AP and the main CP210, and the detailed description will refer to the corresponding description in fig. 2, which is not repeated. The backup optical combiners and the shunt optical combiners included in each AP shown in this embodiment may be optical power adjustable optical combiners. The electrode 1103 in this embodiment tunes the optical power of each output port through the target voltage, so as to achieve the purpose of tuning the optical power in an electronically controlled manner, and in the case that the optical communication system includes a plurality of optical power adjustable optical combiners, the difficulty of tuning the optical power of each output port of each optical power adjustable optical combiners is effectively reduced, and the efficiency of tuning the optical power of each output port is improved.

Specifically, the optical waveguide assembly shown in the present embodiment specifically includes a first optical waveguide arm 1201 and a second optical waveguide arm 1202, and the first optical waveguide arm 1201 and the second optical waveguide arm 1202 constitute a mach-zehnder interferometer (mach-zehnder interferometer, MZI) structure. Specifically, the first optical waveguide arm 1201 is connected to the input port 1111 and the first output port 1112, and the second optical waveguide arm 1202 is connected to the second output port 1113. On the surface of the optical waveguide layer 1102, the first optical waveguide arm 1201 has a first planar region 1203 on both sides and the second optical waveguide arm 1202 has a second planar region 1204 on both sides. Wherein the first optical waveguide arm 1201 and the first plate regions 1203 located at both sides of the first optical waveguide arm 1201 constitute a PN junction (PN junction), and the second optical waveguide arm 1202 and the second plate regions 1204 located at both sides of the second optical waveguide arm 1202 constitute a PN junction. The areas where the first and second optical waveguide arms 1201 and 1202 are close to each other form the first and second optical couplers 1221 and 1222, respectively. Wherein the first optocoupler 1221 is proximate to the input port 1111 and the second optocoupler 1222 is proximate to the first output port 1112 and the second output port 1113.

The electrodes shown in this embodiment specifically include a pair of electrodes 1103 and 1104, the electrodes 1103 are connected to the first optical waveguide arm 1201, the electrodes 1104 are connected to the second optical waveguide arm 1202, and the first voltage transmitted from the electrodes 1103 to the first optical waveguide arm 1201 and the second voltage transmitted from the electrodes 1104 to the second optical waveguide arm 1202 constitute a target voltage, which is a differential voltage. By loading differential voltage on the optical waveguide assembly, the voltage value of the target voltage can be effectively reduced under the condition of guaranteeing to tune the optical power of the first output port 1112 and the optical power of the second output port 1113 with the same size, and the efficiency of tuning the optical power of the output port is improved. Referring to fig. 2, in the first AP230, the first AP-side device 231 is connected to the electrode 1103 and the electrode 1104 in the first main optical combiner 234, and transmits a target voltage to the electrode 1103 and the electrode 1104. Because the main optical combiners of the APs included in the optical communication system can correspond to different optical splitting ratios, the different APs can send different voltages to the main optical combiners included in the optical communication system, so that the main optical combiners of the different APs can tune the optical power based on the different optical splitting ratios, and the tuning process is shown in fig. 4 to 7, which is not repeated in detail. With continued reference to the example shown in fig. 5, the first main optical combiner 234 is an optical power tunable optical combiner. The first AP-side device of the first AP230 sends a target voltage to the electrode included in the first main optical combiner 234, where the target voltage is used to change the arm length difference between the first optical waveguide arm 1201 and the second optical waveguide arm 1202, so that the first main optical combiner 234 tunes the first main link downlink optical power to the second main link downlink optical power and the third main link downlink optical power according to the split ratio corresponding to the first output port and the split ratio corresponding to the second output port, which are specifically shown in fig. 4 and will not be repeated.

The type of the electrode included in the AP is not limited in this embodiment, as long as the target voltage transmitted to the optical waveguide assembly by the electrode can change the arm length difference between the first optical waveguide arm 1201 and the second optical waveguide arm 1202, and thus tune the optical power of the first output port and the optical power of the second output port. For example, the electrodes connected to the first optical waveguide arm 1201 in this embodiment may be ground-signal-ground (GSG) electrode structures, and two of the GSG electrodes are connected to the first plate regions on both sides of the first optical waveguide arm 1201, respectively, and the S electrode is connected to the first optical waveguide arm 1201. For a description of the GSG electrode connected to the second optical waveguide arm 1202, please refer to the description of the GSG electrode connected to the first optical waveguide arm 1201, and detailed description thereof will be omitted. For another example, the electrodes may be GS electrodes, with the S and G electrodes being connected to two different flat areas, e.g., the S electrode being connected to a first flat area and the G electrode being connected to a second flat area.

Taking the first AP230 as an example, the first AP-side device 231 is configured to transmit the target voltage to the first main optical combiner 234, and in particular, the first AP-side device includes a controller configured to transmit the target voltage to an electrode of the first main optical combiner 234. Wherein, the functions of the controller can be partially or completely realized by hardware. The controller shown in this embodiment may be one or more chips, or one or more integrated circuits. For example, the controller may be one or more optical digital signal processing (optical digital signal process, oDSP) chips, field-programmable gate array (FPGA), application specific integrated chips (application specific integrated circuit, ASIC), system on chip (SoC), central processing unit (central processor unit, CPU), network processor (network processor, NP), digital signal processing circuit (digital signal processor, DSP), microcontroller (micro controller unit, MCU), programmable controller (programmable logic device, PLD) or other integrated chips, or any combination of the above chips or controllers, etc.

The controller of each AP shown in this embodiment may store a configuration list for tuning the optical power of the second output port of the main optical combiner, and the AP transmits the target voltage to the main optical combiner according to the configuration list. The configuration list includes the corresponding relationship between the different splitting ratios corresponding to the second output port and the target voltage, and further combines the example shown in fig. 2, where the configuration list can be seen in table 3:

TABLE 3 Table 3

Target voltage	Ratio of light split
		First target voltage	Spectral ratio K1
Second target voltage	Spectral ratio K2
		Third target voltage	Spectral ratio K3

Where the spectral ratio K1< spectral ratio K2< spectral ratio K3, in the case where the distances between the first AP230, the second AP240, and the third AP250 and the master CP gradually increase, in order to ensure that the optical modules of the first AP230, the second AP240, and the third AP250 can receive equal or approximately equal optical powers from the CP210, the controller of the first AP230 sends a first target voltage to the electrode of the first master optical splitter 234 so that the first master optical splitter 234 can tune the optical power of the second output port of the first master optical splitter 234 according to the spectral ratio K1, the controller of the second AP240 sends a second target voltage to the electrode of the second master optical splitter 244 of the second AP so that the second master optical splitter 244 can tune the optical power of the second output port of the second master optical splitter 244 according to the spectral ratio K2, and so on.

For a description of the optical power tuning process of the first output port of the main optical combiner shown in this embodiment, please refer to the description of the optical power tuning of the second output port of the main optical combiner shown in this embodiment, which is not repeated in detail. If the backup optical combiner and the shunt optical combiner of each AP are optical power adjustable optical combiners, the description of the optical power tuning is referred to as a process description of tuning the optical power of the main optical combiner in this embodiment, which is not described in detail.

The optical communication system shown in this embodiment may further include a network management device, where the network management device is connected to each AP, so that the network management device may perform configuration or dynamic adjustment on a configuration list of each AP, so as to implement tuning of optical power of an output port of the optical power tunable optical combiner and splitter remotely. And the network management equipment can store the light splitting proportion of different optical power adjustable light splitters so as to facilitate the operation and maintenance of the optical communication system.

Optionally, the optical power tunable optical combiner shown in this embodiment may also implement power-down protection, where the first optical waveguide arm and the second optical waveguide arm of the optical power tunable optical combiner shown in this embodiment are made of a phase change material (PCM phase change material), respectively. The phase change material is a substance capable of maintaining a constant temperature and thus a constant state of the substance. That is, when the target voltage from the electrode is applied to the first optical waveguide arm and the second optical waveguide arm, there is an arm length difference between the first optical waveguide arm and the second optical waveguide arm. Because the first optical waveguide arm and the second optical waveguide arm are made of phase materials, even if the target voltage is powered down, the first optical waveguide arm and the second optical waveguide arm can maintain the arm length difference unchanged, so that the optical power adjustable optical combiner can continuously tune the optical power of the first output port and the optical power of the second output port according to the arm length difference, and the power-down protection of the optical power adjustable optical combiner is realized.

In the above embodiment, the AP includes the optical power adjustable optical combiner, and in this embodiment, the optical power adjustable optical combiner may also be disposed outside each AP, as shown in fig. 14, and fig. 14 is a structural example diagram of another embodiment of the optical communication system provided in the present application. The example shown in fig. 14 takes the optical communication system of which the networking type is a chain networking as an example. The optical communication system 1400 includes a primary CP1410 and a backup CP1420. The optical communication system 1400 further includes a plurality of APs connected in sequence, and as shown in fig. 14, the optical communication system includes two APs, that is, a first AP1430 and a second AP1440, which are not limited in number. The first AP1430 includes a first AP side device 1431 and a first optical module 1432 connected to the first AP side device 1431, and the description of the structures of the first AP side device 1431 and the first optical module 1432 is shown in the above embodiment, which is not repeated in detail. The second AP1440 includes a second AP-side device 1441 and a second optical module 1442 connected to the second AP-side device 1441, and for a description of the structure of the second AP1440, please refer to the description of the structure of the first AP1430, details of which are not described in detail.

The optical communication system 1400 in this embodiment further includes a main link and a backup link, taking the first AP1430 as an example, in order to implement connection between the first AP1430 and the main link and the backup link, the optical communication system 1400 further includes a first branching optical combiner 1433, a first main optical combiner 1434, and a first backup optical combiner 1435. The description that the first optical module 1432 is connected to the main link through the first splitter optical combiner 1433 and the first main optical combiner 1434, and the description that the first optical module 1431 is connected to the backup link through the first splitter optical combiner 1433 and the first backup optical combiner 1435 are referred to the descriptions shown in fig. 2 to 3, and details are not repeated. The description of the connection of the second optical module of the second AP1440 to the main link and the backup link is referred to as the description of the connection of the first AP1430 to the main link and the backup link, and the description of the connection of the first AP1430 to the main link and the backup link is referred to as the description of the connection of the first AP1430 to the main link and the backup link, which will not be repeated.

In the case that the main optical combiner, the backup optical combiner and the shunt optical combiner are all disposed outside the AP, if the main optical combiner is used as the optical power tunable optical combiner, the main optical combiner needs to have an independent electrode to tune the optical power of the output port of the main optical combiner, and particularly, see fig. 15, where fig. 15 is a structural illustration of one embodiment of the main optical combiner provided in the present application. The main optical combiner 1500 shown in this embodiment includes a power supply 1501, a controller 1502, electrodes 1503, and an optical waveguide assembly 1504. The power supply 1501, the controller 1502 and the electrode 1503 are sequentially connected, the electrode 1503 is connected to the optical waveguide assembly 1504, and the structures of the electrode 1503 and the optical waveguide assembly 1504 are described with reference to fig. 11 to 13, which are not repeated.

In this embodiment, the main optical combiner 1500 is independently provided with a power supply 1501 and a controller 1502, the controller 1502 can obtain a target voltage from the power supply 1501 and send the target voltage to the electrode 1503, so that the optical waveguide component 1504 can split light according to the target voltage, the target voltage and a light splitting process according to the target voltage, which are shown in the above embodiment and will not be described in detail. For the description of the controller 1502, please refer to the description of the controller included in the AP-side device, which is not repeated. If the backup optical combiner and the shunt optical combiner are also optical power adjustable optical combiners, the detailed structure will be described with reference to fig. 15, and details will not be repeated.

In the case where the AP and the optical splitters are separately provided as shown in the present embodiment, the optical splitters for connecting the AP to the main link and the backup link may be provided on an optical distribution frame (optical distribution frame, ODF). Optionally, the ODF may further include a power supply and a controller, where the ODF may further include a plurality of optical power adjustable optical splitters, and the plurality of optical power adjustable optical splitters disposed on the ODF share the power supply and the controller of the ODF.

Fig. 14 is a schematic diagram of an optical communication system, and is not limited to a specific example, the optical communication system may be a ring network. Each AP included in the optical communication system shown in this embodiment may also include any two or any one of a branching optical combiner, a main optical combiner, and a backup optical combiner, which is not specifically limited. The networking type of the optical communication system shown in this embodiment may also be a ring networking, and the description of the ring networking is shown in fig. 8 or fig. 9, and the description of each AP in the ring networking is shown in fig. 14, which is not repeated.

The present application further provides an AP, and the structure of the AP may be referred to the description shown in fig. 2 and fig. 3, which is not described in detail.

The present application provides another AP, see fig. 16, where fig. 16 is a structural example diagram of an embodiment of an AP provided in the present application. The AP includes an optical module 1600 and an AP-side device 1610, the optical module 1600 including a laser 1601, a diode 1602, an amplifier 1603, a shunt optical combiner 1604, a main optical combiner 1605, and a backup optical combiner 1606. The laser 1601 is connected to the AP-side device 1610 and the shunt optical combiner 1604, and the AP-side device 1610, the amplifier 1603, the diode 1602, and the shunt optical combiner 1604 are connected to the main optical combiner 1605 and the backup optical combiner 1606, respectively. For the description of the AP-side device 1610, please refer to the above embodiment, and detailed description is omitted. The diode 1602 may be a diode for photoelectric conversion, such as an avalanche photodiode (avalanche photon diode, APD). The amplifier 1603 may be a transimpedance amplifier (trans-impedance amplifier, TIA).

For example, if the AP needs to send uplink traffic to the master CP via the master link, the AP side device 1610 sends an uplink electrical signal to the laser, the laser 1601 performs electro-optical conversion on the uplink electrical signal to uplink optical power, the laser 1601 sends the uplink optical signal to the master CP through the splitting optical combiner 1604 and the master optical combiner 1605, and the AP sends the uplink optical signal to the master CP via the master link, which is shown in the above embodiment and will not be described in detail. If the main CP transmits the downlink optical power to the AP, the downlink optical power from the main CP is sequentially transmitted to the diode 1602 through the main optical combiner 1605 and the branch optical combiner 1604, the diode 1602 performs photoelectric conversion on the downlink optical power to obtain a downlink electrical signal, and the amplifier 1603 is configured to amplify the downlink electrical signal to obtain an amplified electrical signal, and transmit the amplified electrical signal to the AP-side device 1610. For the description of the uplink optical power and the downlink optical power transmission process shown in the present embodiment, please refer to the above embodiment, and detailed description is omitted.

The above embodiments are merely for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.

Claims

1. An optical communication system, characterized in that the optical communication system comprises a main node and a backup node, and at least one intermediate access node, the optical communication system further comprises a main link and a backup link, each intermediate access node in the at least one intermediate access node is connected with the main node and the backup node through the main link and the backup link respectively, and the intermediate access node is connected with the main link and the backup link through the same included optical module.

2. The optical communication system of claim 1, wherein the at least one intermediate access node comprises a first intermediate access node comprising a first optical module, the optical communication system further comprising a first split optical combiner, a first primary optical combiner, and a first backup optical combiner, the first optical module being coupled to the first split optical combiner, the first split optical combiner being further coupled to the first primary optical combiner and the first backup optical combiner, respectively, and the first primary optical combiner being coupled to the primary link, the first backup optical combiner being coupled to the backup link.

3. The optical communication system of claim 2, wherein the first main optical combiner is an optical power tunable optical combiner, an input port and a first output port of the first main optical combiner are respectively connected to the main link, and a second output port of the first main optical combiner is connected to the first branch optical combiner;

the input port of the first main optical combiner is used for receiving the first main link optical power from the main link, the first main optical combiner is used for tuning the first main link optical power into the second main link optical power and the third main link optical power, the first output port of the first main optical combiner is used for sending the second main link optical power to the main link, the second output port of the first main optical combiner is used for sending the third main link optical power to the first branch optical combiner, and the first branch optical combiner is used for sending the third main link optical power to the first optical module.

4. The optical communication system of claim 3, wherein the at least one intermediate access node further comprises a second intermediate access node comprising a second optical module, the optical communication system further comprising a second optical splitter and a second master optical splitter;

And under the condition that the distance between the first intermediate access node and the main node is smaller than the distance between the second intermediate access node and the main node, the light splitting proportion corresponding to the second output port of the first main light combiner is smaller than the light splitting proportion corresponding to the second output port of the second main light combiner.

5. The optical communication system of claim 4, wherein the optical power output by the second output port of the first main optical combiner is equal to the optical power output by the second output port of the second main optical combiner.

6. The optical communication system according to any one of claims 2 to 5, wherein the first branching optical combiner is an optical combiner with a fixed ratio of optical splitting.

7. The optical communication system according to any one of claims 2 to 5, wherein the first split optical combiner is an optical power tunable optical combiner, a primary port of the first split optical combiner is connected to the first primary optical combiner, and a backup port of the first split optical combiner is connected to the first backup optical combiner;

the first optical splitter is configured to tune optical power of a backup port of the first optical splitter to zero.

8. The optical communication system of any of claims 2 to 7, wherein the first main optical combiner is configured to tune the optical power of the second output of the first main optical combiner to zero if the first optical module is in an abnormal state.

9. The optical communication system according to any one of claims 2 to 8, wherein the first backup optical combiner is an optical power tunable optical combiner, an input port and a first output port of the first backup optical combiner are respectively connected to the backup link, and a second output port of the first backup optical combiner is connected to the first shunt optical combiner;

the input port of the first backup optical combiner is used for receiving the first backup link optical power from the backup link, the first backup optical combiner is used for tuning the first backup link optical power into the second backup link optical power and the third backup link optical power, the first output port of the first backup optical combiner is used for sending the second backup link optical power to the backup link, the second output port of the first backup optical combiner is used for sending the third backup link optical power to the first shunt optical combiner, and the first shunt optical combiner is used for sending the third backup link optical power to the first optical module.

10. The optical communication system according to any of claims 2 to 9, wherein the optical communication system comprises a plurality of said intermediate access nodes connected in sequence, the plurality of intermediate access nodes comprising a first intermediate access node and a last intermediate access node, the main link comprising a first sub-main link and a second sub-main link, the last intermediate access node being connected to one of the plurality of intermediate access nodes by the first sub-main link and the last intermediate access node being connected to the main node by the second sub-main link, the backup link comprising a first sub-backup link and a second sub-backup link, the first intermediate access node being connected to one of the plurality of intermediate access nodes by the first sub-backup link and the first intermediate access node being connected to the backup node by the second sub-backup link.

11. The optical communication system of claim 10, wherein if the transmission of the primary link is switched to the backup link, the primary node is configured to send a first round trip delay time, RTD, to the backup node, the first RTD being an RTD for which optical power is transmitted between the first intermediate access node and the primary node via the primary link; the backup node is configured to obtain a second RTD according to the first RTD, where the second RTD is an RTD that optical power is transmitted between the first intermediate access node and the backup node via the backup link; the backup node is further configured to obtain, via the backup link, uplink optical power from the first intermediate access node according to the second RTD.

12. The optical communication system according to claim 11, wherein the backup node is configured to determine that a difference between a target RTD and the first RTD is the second RTD in the process of obtaining the second RTD from the first RTD, and the target RTD is an RTD that an optical signal is transmitted between the primary node and the backup node sequentially via the plurality of intermediate access nodes.

13. The optical communication system according to claim 11 or 12, wherein the master node is configured to switch transmission of the main link to the backup link by detecting that no uplink optical power transmitted via the main link is received from the first intermediate access node within a preset period of time.

14. The optical communication system of claim 13, wherein the master node is further configured to detect that uplink optical power transmitted via the master link has not been received from a second intermediate access node within the preset time period before the master node switches transmission of the master link to the backup link, and wherein a distance between the first intermediate access node and the master node is smaller than a distance between the second intermediate access node and the master node.

15. The optical communication system of any one of claims 3, 4, 5, 7 or 9, wherein the optical power tunable optical splitter comprises an electrode and an optical waveguide assembly connected to the electrode;

the optical waveguide assembly includes an input port for receiving optical power, a first output port, and a second output port, the electrode for transmitting a target voltage to the optical waveguide assembly, the target voltage for tuning the optical power of the first output port and the optical power of the second output port.

16. The access node is characterized by comprising an optical module, a branching optical multiplexer, a main optical multiplexer and a backup optical multiplexer, wherein the optical module is connected with the branching optical multiplexer, the branching optical multiplexer is also respectively connected with the main optical multiplexer and the backup optical multiplexer, the main optical multiplexer is used for connecting a main link, the backup optical multiplexer is used for connecting a backup link, the main link is used for connecting the optical module and the main node, and the backup link is used for connecting the optical module and the backup node.

17. The access node of claim 16, wherein the primary optical combiner and the backup optical combiner are optical power tunable optical combiners.

18. The access node according to claim 16 or 17, wherein the split optical combiner is a fixed split ratio optical combiner or an optical power tunable optical combiner.

19. The optical module is characterized by comprising a laser, a diode, a shunt optical multiplexer, a main optical multiplexer and a backup optical multiplexer, wherein the laser and the diode are respectively connected with the shunt optical multiplexer, the shunt optical multiplexer is also respectively connected with the main optical multiplexer and the backup optical multiplexer, the main optical multiplexer is used for connecting a main link, the backup optical multiplexer is used for connecting a backup link, the main link is used for connecting the optical module and a main node, and the backup link is used for connecting the optical module and the backup node.

20. The optical module of claim 19 wherein the primary optical combiner and the backup optical combiner are optical power tunable optical combiners.

21. The optical module of claim 19 or 20, wherein the shunt optical combiner is a fixed split ratio optical combiner or an optical power tunable optical combiner.