WO2022227863A1

WO2022227863A1 - Optical communication system, optical signal transmission method, and related device

Info

Publication number: WO2022227863A1
Application number: PCT/CN2022/079463
Authority: WO
Inventors: 周恩宇; 曾小飞; 林斌超
Original assignee: 华为技术有限公司
Priority date: 2021-04-26
Filing date: 2022-03-07
Publication date: 2022-11-03
Also published as: CN115250386A

Abstract

Disclosed in embodiments of the present application are an optical communication system, an optical signal transmission method, and a related device. When optical fiber transmission fails, an ONU closest to a main OLT enables a sub-OLT to replace the main OLT, so that subsequent ONUs can still communicate normally. The optical communication system comprises a main OLT, a first ONU, a second ONU, a first optical splitter, and a second optical splitter. The first ONU comprises a first sub-OLT and a first sub-ONU. A first port of the first optical splitter is connected to the main OLT, a second port of the first optical splitter is connected to the first sub-OLT, a third port of the first optical splitter is connected to the first sub-ONU, a fourth port of the first optical splitter is connected to one of ports of the second optical splitter, and the other port of the second optical splitter is connected to the second ONU. The main OLT is used for sending a target optical signal. If the first sub-ONU cannot receive the target optical signal, the first sub-ONU is used for sending first indication information to the first sub-OLT. The first sub-OLT is used for sending a first optical signal according to the first indication information. The second ONU is used for receiving the first optical signal.

Description

Optical communication system, optical signal transmission method and related equipment

This application claims the priority of the Chinese patent application filed on April 26, 2021 with the State Intellectual Property Office of China, application number 202110454388.2, and the application title is "An Optical Communication System, Optical Signal Transmission Method and Related Equipment", all of which are The contents are incorporated herein by reference.

technical field

The present application relates to the field of optical communication, and in particular, to an optical communication system, an optical signal transmission method, and related equipment.

Background technique

Passive optical network (PON) is an implementation technology of optical access network, and PON is an optical access technology for point-to-multipoint transmission. The optical line terminal (Optical Line Terminal, OLT) is connected to the upper network side equipment, and the lower layer is connected to one or more optical distribution networks (ODN). The ODN includes an optical splitter for optical power distribution, a trunk fiber connected between the optical splitter and the OLT, and branch fibers connected between the optical splitter and each Optical Network Unit (ONU). When transmitting data downstream, the ODN transmits the downstream data of the OLT to each ONU through the optical splitter, and the ONU selectively receives the downstream data carrying its own identity. When transmitting data upstream, the ODN combines the optical signals sent by each ONU into one optical signal and transmits it to the OLT.

The communication network in the mine needs to have scalable characteristics, which can be extended one by one on the basis of the established nodes. For example, there are N nodes in the mine, and nodes N+1 and N+2 can be added after node N according to actual needs. In order to realize the communication of large bandwidth and low delay among the nodes in the mine, the networking architecture of the PON can be applied to the mine communication.

Specifically, the OLT sends downlink optical signals through optical fibers. Each ONU, as a node, is serially connected to the optical fiber in order to receive downlink optical signals. However, when any section of the optical fiber fails, the subsequent ONUs cannot receive optical signals, resulting in abnormal communication.

SUMMARY OF THE INVENTION

Embodiments of the present application provide an optical communication system, an optical signal transmission method, and related equipment. When the optical fiber transmission is normal, the sub-ONU in the ONU works and maintains the original function of the ONU. When the optical fiber transmission fails, the ONU closest to the main OLT enables the sub-OLT to replace the main OLT, so that the subsequent ONUs can still communicate normally, which improves the communication stability.

In a first aspect, the present application provides an optical communication system. The optical communication system includes a main OLT, a first ONU, a second ONU, a first optical splitter and a second optical splitter. The first ONU includes a first sub-OLT and a first sub-ONU. The first port of the first optical splitter is connected to the main OLT. The second port of the first optical splitter is connected to the first sub-OLT. The third port of the first optical splitter is connected to the first sub-ONU. The fourth port of the first optical splitter is connected to one of the ports of the second optical splitter. Another port of the second optical splitter is connected to the second ONU. Specifically, the main OLT is used to transmit the target optical signal. The first sub-ONU is used to receive the target optical signal. If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the second threshold, the first sub-ONU The sub-ONU is used to send the first indication information to the first sub-OLT. The first sub-OLT is used for sending the first optical signal according to the first indication information, and the second ONU is used for receiving the first optical signal.

In this embodiment, a plurality of optical splitters are connected in series on the optical fiber connected to the main OLT, and each optical splitter is connected to an ONU, so that each ONU can receive the downlink optical signal sent by the OLT through the optical fiber. Further, a sub-OLT and a sub-ONU are provided inside each ONU. That is, the ONU in this system has the original function of the ONU and the function of the OLT. When the optical fiber transmission is normal, the sub-ONU in the ONU works and maintains the original function of the ONU. When the optical fiber transmission fails, the ONU closest to the main OLT enables the sub-OLT to replace the main OLT, so that the subsequent ONUs can still communicate normally, which improves the communication stability.

In some possible implementations, the first port of the first optical splitter is used to input the target optical signal. The third port of the first optical splitter is used for outputting the target optical signal to the first sub-ONU. The fourth port of the first optical splitter is used for outputting the target optical signal to the second ONU. If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the change in optical power is greater than the second threshold, the first split The second port of the device is used for inputting the first optical signal. The third port of the first optical splitter is used for outputting the first optical signal to the first sub-ONU. The fourth port of the first optical splitter is used for outputting the first optical signal to the second ONU. In this implementation manner, a 2×2 optical splitter is used, and there are two input ports and two output ports in the downstream direction, which is convenient for matching with the optical communication system provided by the present application.

In some possible implementations, the optical communication system further includes a third optical splitter and a third ONU. Wherein, the second ONU includes a second sub-OLT and a second sub-ONU. The first port of the second optical splitter is connected to the fourth port of the first optical splitter. The second port of the second optical splitter is connected to the second sub-OLT. The third port of the second optical splitter is connected to the second sub-ONU. The fourth port of the second optical splitter is connected to one of the ports of the third optical splitter. Another port of the third optical splitter is connected to the third ONU. The second sub-ONU is used for receiving the target optical signal. If the optical power of the target optical signal received by the second sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the second sub-ONU is weakened and the optical power change value is greater than the second threshold, the second sub-ONU The sub-ONU is used to send the second indication information to the second sub-OLT. The second sub-OLT is configured to send the second optical signal according to the second indication information. The third ONU is used for receiving the second optical signal. In the above manner, the optical communication system provided by the present application can continue to add a third ONU, and can also extend backward one by one on the basis of the existing ONUs, which is convenient for continuous expansion according to actual needs.

In some possible implementations, before the main OLT sends the target optical signal, the main OLT is also used to send a notification message. If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the second threshold, the first sub-ONU The sub-ONU is configured to determine the first time period according to the notification message, and the first indication information includes the first time period. The first sub-OLT is specifically configured to send the first optical signal in the first time period according to the first indication information. If the optical power of the target optical signal received by the second sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the second sub-ONU is weakened and the optical power change value is greater than the second threshold, the second sub-ONU The sub-ONU is configured to determine the second time period according to the notification message, and the second indication information includes the second time period. The second sub-OLT is specifically configured to send the second optical signal in the second time period according to the second indication information. In this embodiment, the main OLT will allocate a corresponding light-emitting period to each ONU. After the main OLT goes offline, the sub-OLTs in each ONU will light up in their corresponding time periods, ensuring that each ONU can emit light according to uniform rules. , which enhances the feasibility of this scheme.

In some possible implementations, the notification message is further used to indicate the total duration of the first period and the second period, and the first period and the second period do not overlap. If the second sub-ONU can only receive the second optical signal within the total duration, the second sub-ONU is used to send the third indication information to the second sub-OLT. The second sub-OLT is configured to continuously send the second optical signal according to the third indication information. In this embodiment, the first sub-OLT and the second sub-OLT emit light in a time-sharing manner, which avoids the conflict between the first sub-OLT and the second sub-OLT, so that the second sub-ONU can recognize the second light sent by the second sub-OLT Signal.

In some possible implementations, there are overlapping periods between the first period and the second period. If the second sub-ONU can identify the second optical signal in the second period, the second sub-ONU is used to send the third indication information to the second sub-OLT. The second sub-OLT is configured to continuously send the second optical signal according to the third indication information. In this embodiment, the first sub-OLT and the second sub-OLT can also emit light at the same time, which improves the flexibility of this solution.

In some possible implementations, the first sub-OLT is also used to receive the uplink optical signal from the second ONU, which improves the practicability of the solution.

In some possible implementations, the wavelength of the target optical signal is the same as the wavelength of the first optical signal to meet standard requirements.

In some possible implementations, the target optical signal includes the target identifier of the main OLT, and the first optical signal includes the first identifier of the first sub-OLT, so that each sub-ONU can identify the sending end of the downlink optical signal.

In a second aspect, the present application provides an optical signal transmission method. The method includes the following steps. The first ONU detects the target optical signal from the main optical line terminal OLT through the first sub-ONU. The first ONU includes a first sub-ONU and a first sub-OLT. If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the second threshold, the first sub-ONU The ONU sends the first optical signal through the first sub-OLT.

In some possible implementations, a first optical splitter is connected between the first ONU and the main OLT, and the first port of the first optical splitter is connected to the main OLT. The second port of the first optical splitter is connected to the first sub-OLT. The third port of the first optical splitter is connected to the first sub-ONU. The fourth port of the first optical splitter is connected to the first port of the second optical splitter, and the second port of the second optical splitter is connected to the second ONU.

In some possible implementations, the first port of the first optical splitter is used to input the target optical signal. The third port of the first optical splitter is used for outputting the target optical signal to the first sub-ONU. The fourth port of the first optical splitter is used for outputting the target optical signal to the second ONU. If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the change in optical power is greater than the second threshold, the first split The second port of the device is used for inputting the first optical signal. The third port of the first optical splitter is used for outputting the first optical signal to the first sub-ONU. The fourth port of the first optical splitter is used for outputting the first optical signal to the second ONU.

In some possible implementations, before the first ONU detects the target optical signal from the main OLT through the first sub-ONU, the method further includes: the first ONU receives a notification message from the main OLT. The sending of the first optical signal by the first ONU through the first sub-OLT includes: the first ONU sending the first optical signal through the first sub-OLT in the first time period indicated by the notification message.

In some possible implementations, if the first sub-ONU cannot detect the target optical signal, the method further includes: the first ONU detects the first optical signal and the second optical signal from the third ONU through the first sub-ONU. The third ONU is used for sending the second optical signal during the second period. Wherein, the first period and the second period do not overlap, and the notification message is further used to indicate the total duration of the first period and the second period. If the first sub-ONU can only receive the first optical signal within the total duration, the first ONU continues to send the first optical signal through the first sub-OLT.

In some possible implementations, if the first sub-ONU cannot detect the target optical signal, the method further includes: the first ONU detects the first optical signal and the second optical signal from the third ONU through the first sub-ONU. The third ONU is used for sending the second optical signal during the second period. Wherein, there is an overlapping period between the first period and the second period. If the first sub-ONU can identify the first optical signal in the first period, the first ONU continues to send the first optical signal through the first sub-OLT.

In some possible implementations, the wavelength of the target optical signal is the same as the wavelength of the first optical signal.

In some possible implementations, the target optical signal includes the target identifier of the main OLT, and the first optical signal includes the first identifier of the first sub-OLT.

In a third aspect, the present application provides an optical signal transmission method. The method includes the following steps. The primary OLT sends a notification message to the first ONU and the second ONU. The first ONU includes a first sub-OLT and a first sub-ONU. The second ONU includes a second sub-OLT and a second sub-ONU. A first optical splitter is connected between the first ONU and the main OLT. The first port of the first optical splitter is connected to the main OLT. The second port of the first optical splitter is connected to the first sub-OLT. The third port of the first optical splitter is connected to the first sub-ONU. The fourth port of the first optical splitter is connected to the first port of the second optical splitter. The second port of the second optical splitter is connected to the second sub-OLT. The third port of the second optical splitter is connected to the second sub-ONU. The main OLT sends the target optical signal to the first ONU and the second ONU. If the first sub-ONU and the second sub-ONU cannot detect the target optical signal from the main OLT, the notification message is used to instruct the first sub-OLT to send the first optical signal in the first period. The notification message is used to instruct the second sub-OLT to send the second optical signal in the second time period.

In a fourth aspect, an embodiment of the present application provides an ONU, where the ONU includes a sub-OLT unit and a sub-ONU unit. The sub-ONU unit is used to detect the target optical signal from the main OLT. If the optical power of the target optical signal received by the sub-ONU unit is lower than the first threshold, and/or, if the optical power of the target optical signal received by the sub-ONU unit is weakened and the optical power change value is greater than the second threshold, the sub-ONU unit is used to send The sub-OLT unit sends indication information. The sub-OLT unit is used for sending the first optical signal according to the indication information.

In some possible implementations, a first optical splitter is connected between the ONU and the main OLT. The first port of the first optical splitter is connected to the main OLT. The second port of the first optical splitter is connected to the sub-OLT unit. The third port of the first optical splitter is connected to the sub-ONU unit. The fourth port of the first optical splitter is connected to the first port of the second optical splitter. The second port of the second optical splitter is connected to the second ONU.

In some possible implementations, the first port of the first optical splitter is used to input the target optical signal. The third port of the first optical splitter is used for outputting the target optical signal to the sub-ONU unit. The fourth port of the first optical splitter is used for outputting the target optical signal to the second ONU. If the optical power of the target optical signal received by the sub-ONU unit is lower than the first threshold, and/or, if the optical power of the target optical signal received by the sub-ONU unit is weakened and the optical power change value is greater than the second threshold, the second optical splitter of the first optical splitter. The port is used for inputting the first optical signal. The third port of the first optical splitter is used for outputting the first optical signal to the sub-ONU unit. The fourth port of the first optical splitter is used for outputting the first optical signal to the second ONU.

In some possible implementations, before the sub-ONU unit is used for detecting the target optical signal from the main OLT, the sub-ONU unit is further used for receiving a notification message from the main OLT. If the sub-ONU unit cannot receive the target optical signal, the sub-ONU unit is used to determine the first time period according to the notification message. The indication information includes the first time period. The sub-OLT unit is specifically configured to send the first optical signal in the first time period according to the indication information.

In some possible implementations, if the sub-ONU unit cannot detect the target optical signal, the sub-ONU unit is further configured to detect the first optical signal and the second optical signal from the third ONU. The third ONU is used for sending the second optical signal during the second period. Wherein, the first period and the second period do not overlap, and the notification message is further used to indicate the total duration of the first period and the second period. If the sub-ONU unit can only receive the first optical signal within the total duration, the sub-OLT unit continues to send the first optical signal.

In some possible implementations, if the sub-ONU unit cannot detect the target optical signal, the sub-ONU unit is further configured to detect the first optical signal and the second optical signal from the third ONU. The third ONU is used for sending the second optical signal during the second period. Wherein, there is an overlapping period between the first period and the second period. If the sub-ONU unit can identify the first optical signal in the first period, the sub-OLT unit continues to send the first optical signal.

In some possible implementations, the target optical signal includes the target identifier of the main OLT, and the first optical signal includes the first identifier of the sub-OLT unit.

In a fifth aspect, an embodiment of the present application provides an OLT, where the OLT includes a processor and an optical transceiver. The processor and the optical transceiver are interconnected by wires. A processor is configured to perform the steps as in the method of the third aspect.

In some possible implementations, the OLT further includes a memory, and the processor invokes the program code in the memory for performing the steps in the method of the third aspect.

In the embodiment of the present application, a plurality of optical splitters are connected in series on the optical fiber connected to the main OLT, and each optical splitter is connected to an ONU, so that each ONU can receive the downlink optical signal sent by the OLT through the optical fiber. Further, a sub-OLT and a sub-ONU are provided inside each ONU. That is, the ONU in this system has the original function of the ONU and the function of the OLT. When the optical fiber transmission is normal, the sub-ONU in the ONU works and maintains the original function of the ONU. When the optical fiber transmission fails, the ONU closest to the main OLT enables the sub-OLT to replace the main OLT, so that the subsequent ONUs can still communicate normally, which improves the communication stability.

Description of drawings

Fig. 1 is the structural representation of the PON system in the mine;

FIG. 2 is a schematic structural diagram of an optical communication system in an embodiment of the application;

3 is a schematic structural diagram of an ONU in an embodiment of the application;

FIG. 4 is a schematic flowchart of an optical signal transmission method provided by an embodiment of the present application;

5 is a schematic structural diagram of a possible ONU in the application;

6 is a schematic structural diagram of another possible ONU in the application;

FIG. 7 is a schematic structural diagram of another possible main OLT in this application.

Detailed ways

It should be noted that the terms "first", "second", "third" and "fourth" in the description and claims of the present application and the above drawings are used to distinguish similar objects, rather than limiting specific order or sequence. It is to be understood that the above terms are interchangeable under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those described herein. Furthermore, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units expressly listed, but may include steps or units not expressly listed or for such process, method, product or Other steps or units inherent to the device.

The embodiments of the present application are mainly applied to the communication system in the mine, and the nodes in the mine are connected in series through lines in sequence. First of all, the communication system in the mine must be scalable. On the basis of existing nodes, it can be extended one by one. For example, after node N, node N+1 can be added. Secondly, the communication system in the mine should be able to realize the self-organized network. For example, if the line between any two nodes fails, other nodes can still communicate with each other. In order to realize large bandwidth and low latency communication between nodes in the mine, the networking architecture of passive optical network (PON) can also be applied to mine communication.

Figure 1 is a schematic structural diagram of a PON system in a mine. As shown in Figure 1, the PON system adopts a chain-type networking structure. The main OLT is connected to the trunk fiber, and the trunk fiber is also connected with a plurality of optical splitters in series. In addition, each optical splitter is also connected to the corresponding ONU through a branch optical fiber. That is to say, each ONU can be regarded as a node, and each node is serially connected to the backbone fiber through its own connected optical splitter. The main OLT sends the downlink optical signal through the backbone optical fiber, and each ONU receives the downlink optical signal through the branch optical fiber and selects the required information from it. However, when any section of the backbone fiber fails, the subsequent ONUs cannot receive optical signals, resulting in abnormal communication. For example, if the backbone fiber between ONU1 and ONU2 fails, all the ONUs after ONU1 including ONU2 will not be able to receive the downlink optical signal sent by the main OLT. This leads to abnormal communication in the mine, which brings great security risks.

Therefore, the present application provides an optical communication system. When the optical fiber transmission fails, the ONU closest to the main OLT enables the sub-OLT to replace the main OLT, so that the subsequent ONUs can still communicate normally, and the communication stability is improved.

FIG. 2 is a schematic structural diagram of an optical communication system in an embodiment of the present application. As shown in FIG. 2 , the optical communication system includes but is not limited to the main OLT 10, the ONU 20, the ONU 30, the ONU 40, the optical splitter 50, the optical splitter 60 and the optical splitter 70. Wherein, ONU 20 includes sub-OLT 201 and sub-ONU 202, ONU 30 includes sub-OLT 301 and sub-ONU 302, and ONU 40 includes sub-OLT 401 and sub-ONU 402. Optical splitter 50 , optical splitter 60 and optical splitter 70 are all 2×2 optical splitters, that is, each optical splitter has two input ports and two output ports. Specifically, port 1 of the optical splitter 50 is connected to the main OLT 10, port 2 of the optical splitter 50 is connected to the sub-OLT 201, and port 3 of the optical splitter 50 is connected to the sub-ONU 202. Port 1 of the optical splitter 60 is connected to port 4 of the optical splitter 50, port 2 of the optical splitter 60 is connected to the sub-OLT 301, and port 3 of the optical splitter 60 is connected to the sub-ONU 302. Port 1 of the optical splitter 70 is connected to port 4 of the optical splitter 60, port 2 of the optical splitter 70 is connected to the sub-OLT 401, and port 3 of the optical splitter 70 is connected to the sub-OLT 402. It should be understood that on the basis of the system structure shown in FIG. 2 , more ONUs and optical splitters can be expanded in turn according to the above-mentioned connection methods, the subsequently expanded ONUs also have sub-OLTs and sub-ONUs, and the subsequently expanded optical splitters also all have sub-OLTs and sub-ONUs. is a 2×2 beam splitter.

It should be noted that the ONU in the above-mentioned optical communication system is different from the traditional ONU, and the ONU provided by the present application not only has the function of the ONU, but also has the function of the OLT. That is, the sub-ONUs in each ONU are used to implement the functions of the ONU, and the sub-OLTs in each ONU are used to implement the functions of the OLT. The ONU provided by this application is further introduced below by taking the ONU 20 as an example.

FIG. 3 is a schematic structural diagram of an ONU in an embodiment of the present application. As shown in FIG. 3 , the sub-OLT 201 includes an optical module 201a and a media access control (Media Access Control, MAC) chip 201b, and the sub-ONU 202 includes an optical module 202a and a MAC chip 202b. That is to say, the sub-OLT 201 and the sub-ONU 202 are two independent devices with their own optical modules and MAC chips respectively. The sub-OLT 201 is similar in structure to the traditional OLT, and the sub-ONU 202 is also similar in structure to the traditional ONU. The ONU 20 provided in this application can be regarded as a device integrating the sub-OLT 201 and the sub-ONU 202, and the sub-OLT 201 and the sub-ONU 202 can also communicate.

It should be understood that the main purpose of configuring a sub-OLT in each ONU is to allow the sub-OLT to replace the main OLT after a line failure to ensure that the system can continue to work normally. Specifically, when the lines of the optical communication system are normal, each ONU can receive the downlink optical signal sent by the main OLT. At this time, each ONU only needs to enable the local sub-ONU to maintain the function of its own ONU. However, if one of the lines is faulty, the ONUs following the faulty line will not be able to receive the optical signal sent by the main OLT. At this time, after the faulty line, an ONU closest to the main OLT will enable the local sub-OLT to send downlink optical signals instead of the main OLT, so as to ensure that other subsequent ONUs can communicate normally. Taking FIG. 2 as an example, if the line between the optical splitter 50 and the optical splitter 60 fails, the ONU 30 and the ONU 40 will not be able to receive the downlink optical signal from the main OLT. At this time, the ONU 30 needs to enable the local sub-OLT 301 to replace the main OLT to send downlink optical signals. That is, the ONU 30 enables the OLT function, and the ONU 40 still maintains the original ONU function. The ONU with the local sub-OLT enabled will form a new PON system with other ONUs, and the other ONUs will re-register and go online.

It should be noted that each ONU can determine whether to receive an optical signal from the main OLT according to the optical power of the received optical signal. The conditions for determining that each ONU cannot receive the optical signal sent by the main OLT include but are not limited to the following. First, the optical power of the optical signal received by the ONU is lower than the first threshold. Second, the optical power of the optical signal received by the ONU is weakened and the change value of the optical power is greater than the second threshold.

It should also be understood that, based on the special structure of the ONU provided by the present application, the present application adopts a 2×2 optical splitter, which has two input ports and two output ports in the downstream direction. Taking the optical splitter 50 as an example, the downlink optical signal sent by the main OLT 10 is input from port 1, output from port 3 to the sub-ONU 202, and output from port 4 to the optical splitter 60. After the sub-OLT 201 works in place of the main OLT 10, the downlink optical signal sent by the sub-OLT 201 is input from port 2 and output from port 4 to the optical splitter 60. It should be noted that the present application may also use a 2×3 optical splitter or a 2×4 optical splitter, etc., which is not specifically limited here.

In some possible implementations, if the sub-OLT in an ONU starts to work instead of the main OLT, the sub-ONU in the ONU can be stopped to reduce power consumption. Of course, the sub-ONU in the ONU can also be selected. The ONU continues to work, which is not limited here. Similarly, if the sub-ONU in a certain ONU keeps working normally, the local sub-OLT can be temporarily disabled. After the sub-OLT works in place of the main OLT, the wavelength of the downlink optical signal sent by the sub-OLT should be the same as the wavelength of the downlink optical signal sent by the main OLT to meet the standard requirements. The downlink optical signal sent by the main OLT and the downlink optical signal sent by each sub-OLT should have their own identifiers, so that other ONUs can distinguish the received optical signals. In addition, each sub-OLT is similar to the main OLT, in addition to sending downlink optical signals, it can also receive uplink optical signals. However, before the sub-OLT formally replaces the main OLT to work, the received uplink optical signal may not be processed.

The following first takes the ONU 20 as an example to introduce the specific working mode of the ONU in the embodiment of the present application. Specifically, the sub-ONU 202 is used to receive the downlink optical signal from the main OLT 10. If the line between the main OLT 10 and the ONU 20 fails, the sub-ONU 202 cannot receive the downlink optical signal from the main OLT 10. Then, the sub-ONU 202 can send instruction information to the sub-OLT 201 to instruct the sub-OLT 201 to send the downlink optical signal. It should be understood that since the ONU 20 is the ONU closest to the main OLT 10, as long as the sub-ONU 202 cannot receive the downlink optical signal, the sub-OLT 201 is enabled, and its judgment logic is relatively simple.

However, for other ONUs behind the ONU 20, if the downlink optical signal from the main OLT 10 cannot be received, the local sub-OLT does not necessarily need to be started directly. Unless the ONU cannot receive the downstream optical signals sent by other sub-OLTs, the local sub-OLT will be enabled. For example, the ONU 20, ONU 30 and ONU 40 cannot receive the downlink optical signal sent by the main OLT 10, and the line between the main OLT 10 and the ONU 20 must be faulty. However, it is unknown whether the line between ONU 20 and ONU 30 and the line between ONU 30 and ONU 40 are faulty. If the ONU 30 cannot receive the downlink optical signal from the sub-OLT 201, it means that the line between the ONU 20 and the ONU 30 is also faulty, and the sub-OLT 301 needs to be enabled at this time.

To this end, the present application provides various detection mechanisms to help each ONU determine whether a local sub-OLT needs to be enabled. It should be noted that the various detection mechanisms introduced below are applicable to each ONU in the optical communication system.

Detection mechanism 1:

The main OLT will allocate corresponding light-emitting time slots to each ONU, so that after each ONU cannot receive the downlink optical signal from the main OLT, the sub-OLTs in each ONU send optical signals in different time periods. Specifically, the master OLT will issue a notification message to inform each ONU of the corresponding lighting time slot and the total lighting duration of all ONUs. For example, if the ONU 20, ONU 30 and ONU 40 cannot receive the downlink optical signal sent by the main OLT 10, the sub-OLT 201 emits light during the delay period of 20ms-40ms, the sub-OLT 301 emits light during the delay period of 40ms-60ms, and the sub-OLT 301 emits light during the delay period of 40ms-60ms. The OLT 401 emits light for a period of delay of 60ms-80ms, and so on. In this way, each sub-OLT emits light in sequence, which avoids the conflict caused by the simultaneous lighting of multiple sub-OLTs, and facilitates each sub-ONU to identify the received optical signal. The following takes the ONU 40 as an example to introduce the way of judging whether to enable the local sub-OLT.

In addition to receiving the optical signals sent by the sub-OLT 201 and the sub-OLT 301, the sub-ONU 402 also needs to receive the optical signal sent by the local sub-OLT 401. In addition, the sub-ONU 402 can learn the light-emitting time slot of the sub-OLT 401 and the total light-emitting duration of all the sub-OLTs through the notification message sent by the main OLT. Therefore, if the sub-ONU 402 can only receive the optical signal sent by the sub-OLT 401 within the total duration of all sub-OLTs emitting light, the sub-ONU 402 instructs the sub-OLT 401 to continuously transmit the optical signal. On the contrary, the sub-ONU 402 instructs the sub-OLT 401 to suspend the transmission of optical signals, and maintains the work of the sub-ONU 402. It should be noted that the optical signal sent by each sub-OLT carries its own identification, so that the sub-ONU 402 can identify the received optical signal.

Detection mechanism 2:

Different from the above detection mechanism 1, the sub-OLTs in each ONU do not emit light sequentially, and the light-emitting periods of each sub-OLT may overlap. In a possible implementation manner, the master OLT will issue a notification message to inform each ONU of the corresponding light-emitting time slot. Among them, the light-emitting time slots of each ONU neutron OLT completely overlap or partially overlap. In another possible implementation manner, the sub-OLTs in each ONU can emit light with random delay. Due to the randomness of the delay, there is a high probability that multiple sub-OLTs emit light in the same time period. For example, if the ONU 20, ONU 30 and ONU 40 cannot receive the downlink optical signal sent by the main OLT 10, the sub-OLT 201 emits light during the delay period of 20ms-40ms, the sub-OLT 301 emits light during the delay period of 30ms-50ms, and the sub-OLT 301 emits light during the delay period of 30ms-50ms. The OLT 401 emits light for a period of delay of 25ms-45ms. Compared with the above detection mechanism 1, the way of judging whether to enable the local sub-OLT has also changed accordingly. The following takes the ONU 40 as an example to introduce the way of judging whether to enable the local sub-OLT.

In addition to receiving the optical signals sent by the sub-OLT 201 and the sub-OLT 301, the sub-ONU 402 also needs to receive the optical signal sent by the local sub-OLT 401. It should be understood that other sub-OLTs will also emit light during the period when the sub-OLT 401 is emitting light. If the sub-ONU 402 receives optical signals sent by a plurality of sub-OLTs during the light-emitting period of the sub-OLT 401, a conflict will be caused, resulting in the failure of the sub-ONU 402. Identify the optical signal sent by the sub-OLT 401. Therefore, if the sub-ONU 402 can recognize the optical signal sent by the sub-OLT 401 during the period when the sub-OLT 401 emits light, the sub-ONU 402 instructs the sub-OLT 401 to continuously transmit the optical signal. On the contrary, the sub-ONU 402 instructs the sub-OLT 401 to suspend the transmission of optical signals, and maintains the work of the sub-ONU 402. Through the above method, each sub-OLT is not strictly required to emit light in different time periods, the light-emitting mode of each sub-OLT is more flexible, and it can help each ONU to determine whether the local sub-OLT needs to be activated in a relatively short period of time.

It should be noted that, in practical applications, in addition to the two detection mechanisms listed above, there may also be other methods for detection, which are not specifically limited here. For example, based on the above detection mechanism 2, in the case where the sub-OLTs in each ONU use random delay to emit light, if the sub-ONU 402 recognizes the optical signals sent by other sub-OLTs except the sub-OLT 401, it will suspend the sub-OLT 401. glow.

It should be understood that during the period of executing the above detection mechanism, the sub-OLT and the sub-ONU in each ONU need to work simultaneously. The sub-OLT is enabled at this stage only to temporarily emit light to cooperate with the detection, and is not officially enabled. The sub-OLT that is officially activated after the detection ends needs to replace the main OLT to continuously emit light. In addition, the ONU 20 closest to the main OLT 10 also needs to implement the above-mentioned detection mechanism. If the sub-ONU 202 cannot receive the optical signal sent by the sub-OLT 201, it means that the line between the ONU 20 and the optical splitter 50 may be faulty. Lighting of the sub OLT 201 needs to be suspended.

Based on the technology of the above-mentioned optical communication system, the optical signal transmission method applied to the optical communication system will be introduced below. It should be noted that, the system structure corresponding to the following optical signal transmission method may be as described in the above-mentioned embodiments of the optical communication system. However, it is not limited to the optical communication system described above.

FIG. 4 is a schematic flowchart of an optical signal transmission method provided by an embodiment of the present application. It should be noted that, the optical communication system in this embodiment may be specifically the optical communication system shown in 2 above. For ease of introduction, the following embodiments are mainly introduced based on an optical communication system composed of a main OLT and two ONUs. In this example, the optical signal transmission method includes the following steps.

401. The primary OLT sends a notification message to the first ONU and the second ONU.

In this embodiment, the first ONU is the ONU closest to the main OLT. For example, the first ONU may correspond to the ONU 20 shown in the above-mentioned FIG. 2 , and the second ONU may correspond to the ONU 30 shown in the above-mentioned FIG. 2 . The main OLT will allocate corresponding light-emitting periods to the first ONU and the second ONU respectively, and notify the first ONU and the second ONU by sending a notification message.

402. The first ONU determines, according to the notification message, a first period of time during which the first sub-OLT emits light.

Specifically, the first sub-ONU determines the first time period corresponding to the notification message after receiving the notification message, and further, the first sub-ONU may notify the first sub-OLT of the first time period by sending a message to the first sub-OLT.

403. The second ONU determines, according to the notification message, a second period during which the second sub-OLT emits light.

Specifically, the second sub-ONU determines the second time period corresponding to the notification message after receiving the notification message, and further, the second sub-ONU may notify the second sub-OLT of the second time period by sending a message to the second sub-OLT.

404. The main OLT sends the target optical signal to the first ONU and the second ONU.

405. The first sub-ONU judges whether the target optical signal is detected, and if yes, executes step 406, and if not, executes step 407.

406. If the first sub-ONU detects the target optical signal, the first ONU maintains the operation of the first sub-ONU.

407. If the first sub-ONU does not detect the target optical signal, the first sub-ONU sends first indication information to the first sub-OLT for instructing the first sub-OLT to send the first optical signal.

408. The second sub-ONU judges whether the target optical signal is detected, and if yes, executes step 409, and if not, executes step 410.

409. If the second sub-ONU detects the target optical signal, the second ONU keeps the second sub-ONU working.

410. If the second sub-ONU does not detect the target optical signal, the second sub-ONU sends second indication information to the second sub-OLT for instructing the second sub-OLT to send the second optical signal.

411. The first sub-OLT sends the first optical signal in the first time period according to the first indication information.

412. The second sub-OLT sends a second optical signal in a second time period according to the second indication information.

413. The first ONU detects the first optical signal, and selects a working mode according to the detection result.

Specifically, the first sub-ONU is used to detect the first optical signal sent by the first sub-OLT. If the first sub-ONU can detect the first optical signal, the first sub-ONU will notify the first sub-OLT to continuously send the first optical signal. That is, the first ONU officially enables the first sub-OLT. On the contrary, the first sub-ONU will notify the first sub-OLT to suspend sending the first optical signal, and maintain the operation of the first sub-ONU.

414. The second ONU detects the first optical signal and the second optical signal, and selects the working mode according to the detection result.

Specifically, the second sub-ONU is used to detect the first optical signal and the second optical signal. It should be understood that, based on whether the first period and the second period overlap, the second sub-ONU will use different detection mechanisms to determine whether the second sub-OLT needs to be enabled. For details, please refer to the various detection mechanisms provided by the embodiment shown in FIG. 2 , which will not be repeated here. If the second sub-ONU determines through detection that the second OLT is to be officially activated, the second sub-ONU will notify the second sub-OLT to continuously send the second optical signal. On the contrary, the second sub-ONU will notify the second sub-OLT to suspend sending the second optical signal, and maintain the operation of the second sub-ONU.

The main OLT and ONU provided by the present application are introduced respectively below.

FIG. 5 is a schematic structural diagram of a possible ONU in this application. The ONU includes a sub-OLT unit 501 and a sub-ONU unit 502, and the sub-OLT unit 501 and the sub-ONU unit 502 are connected to each other through lines. Specifically, the ONU may be any one of the ONUs in the above-mentioned embodiments shown in FIG. 2 and FIG. 4 . The sub-OLT unit 501 is configured to perform the operation of any one of the sub-OLTs in the above-mentioned embodiments shown in FIG. 2 and FIG. 4 , and the sub-ONU unit 502 is used to perform the operation of any one of the sub-ONUs in the above-mentioned embodiments shown in FIG. 2 and FIG. 4 .

FIG. 6 is a schematic structural diagram of another possible ONU in this application. The sub-OLT unit 501 includes the processor 501a and the optical transceiver 501c. The processor 501a and the optical transceiver 501c are connected to each other by wires. It should be noted that the optical transceiver 501c is configured to perform the operation of transmitting and receiving signals by the sub-OLT in the embodiments shown in FIG. 2 and FIG. 4 . The processor 501a is configured to perform other operations of the sub-OLT except for signal transceiving in the above-mentioned embodiments shown in FIG. 2 and FIG. 4 . Optionally, the sub-OLT unit 501 further includes a memory 501b, wherein the memory 501b is used to store program instructions and data. The sub-ONU unit 502 includes the processor 502a and the optical transceiver 502c. The processor 502a and the optical transceiver 502c are interconnected by wires. It should be noted that, the optical transceiver 502c is configured to perform the operation of transmitting and receiving signals by the sub-ONU in the embodiments shown in FIG. 2 and FIG. 4 . The processor 502a is configured to perform other operations of the sub-ONU except for signal transceiving in the embodiments shown in FIG. 2 and FIG. 4 . Optionally, the sub-ONU unit 502 further includes a memory 501b, wherein the memory 502b is used to store program instructions and data.

In a possible implementation manner, the above-mentioned processor 501a includes the MAC chip 201b shown in FIG. 3 , and the above-mentioned optical transceiver 501c includes the optical module 201a shown in FIG. 3 . The above-mentioned processor 502a includes the MAC chip 202b shown in FIG. 3 , and the above-mentioned optical transceiver 502c includes the optical module 202a shown in FIG. 3 .

FIG. 7 is a schematic structural diagram of another possible main OLT in this application. Main OLT packet processor 701 and optical transceiver 703. The processor 701 and the optical transceiver 703 are interconnected by wires. It should be noted that, the optical transceiver 703 is configured to perform the operation of transmitting and receiving signals by the main OLT in the embodiments shown in FIG. 2 and FIG. 4 . The processor 701 is configured to perform other operations of the main OLT except for signal transmission and reception in the above-mentioned embodiments shown in FIG. 2 and FIG. 4 . Optionally, the main OLT further includes a memory 702, wherein the memory 702 is used to store program instructions and data.

It should be noted that the processors shown in FIG. 6 and FIG. 7 may adopt a general-purpose central processing unit (Central Processing Unit, CPU), a microprocessor, an application-specific integrated circuit ASIC, or at least one integrated circuit for Relevant programs are executed to realize the technical solutions provided by the embodiments of the present application. The memory shown in Figures 6 and 7 above may store operating systems and other applications. When implementing the technical solutions provided by the embodiments of the present application through software or firmware, program codes for implementing the technical solutions provided by the embodiments of the present application are stored in a memory and executed by a processor. In one embodiment, a memory may be included within the processor. In another embodiment, the processor and memory are two separate structures.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above may refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above embodiments can be completed by hardware, or can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. The storage medium mentioned may be read only memory, random access memory, or the like. Specifically, for example, the above-mentioned processing unit or processor may be a central processing unit, a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices , transistor logic devices, hardware components, or any combination thereof. Whether the above functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of this application.

When implemented in software, the method steps described in the above embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVD), or semiconductor media (eg, Solid State Disk (SSD)), and the like.

Claims

An optical communication system, characterized in that the optical communication system comprises a main optical line terminal OLT, a first optical network unit ONU, a second ONU, a first optical splitter and a second optical splitter, wherein the first ONU It includes a first sub-OLT and a first sub-ONU, a first port of the first optical splitter is connected to the main OLT, a second port of the first optical splitter is connected to the first sub-OLT, and the first optical splitter is connected to the first sub-OLT. The third port of an optical splitter is connected to the first sub-ONU, the fourth port of the first optical splitter is connected to one of the ports of the second optical splitter, and the other port of the second optical splitter is connected to The second ONU is connected;

The main OLT is used to send the target optical signal;

The first sub-ONU is used to receive the target optical signal, if the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the target optical signal received by the first sub-ONU The optical power of the device is weakened and the change value of the optical power is greater than the second threshold, sending first indication information to the first sub-OLT;

the first sub-OLT is configured to send a first optical signal according to the first indication information;

The second ONU is used for receiving the first optical signal.
The optical communication system according to claim 1, wherein the first port of the first optical splitter is used to input the target optical signal, and the third port of the first optical splitter is used to transmit the target optical signal to the first optical splitter. A sub-ONU outputs the target optical signal, and the fourth port of the first optical splitter is used to output the target optical signal to the second ONU;

If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the the second threshold, the second port of the first optical splitter is used to input the first optical signal, and the third port of the first optical splitter is used to output the first optical signal to the first sub-ONU signal, the fourth port of the first optical splitter is used for outputting the first optical signal to the second ONU.
The optical communication system according to claim 1 or 2, wherein the optical communication system further comprises a third optical splitter and a third ONU, wherein the second ONU comprises a second sub-OLT and a second sub-ONU , the first port of the second optical splitter is connected to the fourth port of the first optical splitter, the second port of the second optical splitter is connected to the second sub-OLT, and the second optical splitter The third port is connected to the second sub-ONU, the fourth port of the second optical splitter is connected to one of the ports of the third optical splitter, and the other port of the third optical splitter is connected to the third optical splitter ONU is connected;

The second sub-ONU is configured to receive the target optical signal, if the optical power of the target optical signal received by the second sub-ONU is lower than the first threshold, and/or if the target optical signal received by the second sub-ONU The optical power of the optical signal is weakened and the change value of the optical power is greater than the second threshold, the second sub-ONU is used to send the second indication information to the second sub-OLT;

the second sub-OLT is configured to send a second optical signal according to the second indication information;

The third ONU is used for receiving the second optical signal.
The optical communication system according to claim 3, wherein before the main OLT sends the target optical signal, the main OLT is further configured to send a notification message;

If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the the second threshold, the first sub-ONU is used to determine the first period according to the notification message, and the first indication information includes the first period;

The first sub-OLT is specifically configured to send the first optical signal in the first time period according to the first indication information;

If the optical power of the target optical signal received by the second sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the second sub-ONU is weakened and the optical power change value is greater than the the second threshold, the second sub-ONU is used to determine a second time period according to the notification message, and the second indication information includes the second time period;

The second sub-OLT is specifically configured to send the second optical signal in the second time period according to the second indication information.
The optical communication system according to claim 4, wherein the notification message is further used to indicate the total duration of the first time period and the second time period, and the first time period and the second time period are different from each other. overlapping;

If the second sub-ONU can only receive the second optical signal within the total duration, the second sub-ONU is configured to send third indication information to the second sub-OLT;

The second sub-OLT is configured to continuously send the second optical signal according to the third indication information.
The optical communication system according to claim 4, wherein there is an overlapping period between the first period and the second period;

If the second sub-ONU can identify the second optical signal during the second period, the second sub-ONU is configured to send third indication information to the second sub-OLT;

The second sub-OLT is configured to continuously send the second optical signal according to the third indication information.
The optical communication system according to any one of claims 1 to 6, wherein the first sub-OLT is further configured to receive an uplink optical signal from the second ONU.
The optical communication system according to any one of claims 1 to 7, wherein the wavelength of the target optical signal is the same as the wavelength of the first optical signal.
The optical communication system according to any one of claims 1 to 8, wherein the target optical signal includes a target identifier of the main OLT, and the first optical signal includes a second optical signal of the first sub-OLT. an identification.
A method for transmitting an optical signal, comprising:

The first optical network unit ONU detects the target optical signal from the main optical line terminal OLT through the first sub-ONU, and the first ONU includes the first sub-ONU and the first sub-OLT;

If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the If the second threshold is exceeded, the first ONU sends the first optical signal through the first sub-OLT.
The method according to claim 10, wherein a first optical splitter is connected between the first ONU and the main OLT, a first port of the first optical splitter is connected to the main OLT, and the first optical splitter is connected to the main OLT. The second port of the first optical splitter is connected to the first sub-OLT, the third port of the first optical splitter is connected to the first sub-ONU, and the fourth port of the first optical splitter is connected to the second sub-ONU. The first port of the optical splitter is connected to the second ONU, and the second port of the second optical splitter is connected to the second ONU.
The method according to claim 11, wherein the first port of the first optical splitter is used for inputting the target optical signal, and the third port of the first optical splitter is used for sending the target optical signal to the first optical splitter. The ONU outputs the target optical signal, and the fourth port of the first optical splitter is used to output the target optical signal to the second ONU;

If the optical power of the target optical signal received by the first sub-ONU is lower than the first threshold, and/or, if the optical power of the target optical signal received by the first sub-ONU is weakened and the optical power change value is greater than the the second threshold, the second port of the first optical splitter is used to input the first optical signal, and the third port of the first optical splitter is used to output the first optical signal to the first sub-ONU signal, the fourth port of the first optical splitter is used for outputting the first optical signal to the second ONU.
The method according to any one of claims 10 to 12, wherein before the first ONU detects the target optical signal from the main OLT through the first sub-ONU, the method further comprises: :

The first ONU receives a notification message from the main OLT;

The sending of the first optical signal by the first ONU through the first sub-OLT includes:

The first ONU sends the first optical signal during the first period indicated by the notification message through the first sub-OLT.
The method according to claim 13, wherein if the first sub-ONU cannot detect the target optical signal, the method further comprises:

The first ONU detects the first optical signal and the second optical signal from the third ONU through the first sub-ONU, and the third ONU is used to send the second optical signal in the second period, wherein the The first period and the second period do not overlap, and the notification message is further used to indicate the total duration of the first period and the second period;

If the first sub-ONU can only receive the first optical signal within the total duration, the first ONU continues to send the first optical signal through the first sub-OLT.
The method according to claim 13, wherein if the first sub-ONU cannot detect the target optical signal, the method further comprises:

The first ONU detects the first optical signal and the second optical signal from the third ONU through the first sub-ONU, and the third ONU is used to send the second optical signal in the second period, wherein the There is an overlapping period between the first period and the second period;

If the first sub-ONU can identify the first optical signal in the first period, the first ONU continues to send the first optical signal through the first sub-OLT.
The method according to any one of claims 10 to 15, wherein the wavelength of the target optical signal is the same as the wavelength of the first optical signal.
The method according to any one of claims 10 to 16, wherein the target optical signal includes a target identifier of the main OLT, and the first optical signal includes a first identifier of the first sub-OLT .
A method for transmitting an optical signal, comprising:

The main OLT sends a notification message to the first ONU and the second ONU, the first ONU includes the first sub-OLT and the first sub-ONU, the second ONU includes the second sub-OLT and the second sub-ONU, the first sub-OLT and the second sub-ONU A first optical splitter is connected between the ONU and the main OLT, a first port of the first optical splitter is connected to the main OLT, and a second port of the first optical splitter is connected to the first sub-OLT , the third port of the first optical splitter is connected to the first sub-ONU, the fourth port of the first optical splitter is connected to the first port of the second optical splitter, and the second optical splitter of the second optical splitter The port is connected to the second sub-OLT, and the third port of the second optical splitter is connected to the second sub-ONU;

The main OLT sends the target optical signal to the first ONU and the second ONU. If the first sub-ONU and the second sub-ONU cannot detect the target optical signal from the main OLT, then the The notification message is used to instruct the first sub-OLT to send the first optical signal in the first time period, and the notification message is used to instruct the second sub-OLT to send the second optical signal in the second time period.
An optical network unit ONU, comprising: a sub-OLT unit and a sub-ONU unit;

The sub-ONU unit is used to detect the target optical signal from the main OLT;

If the optical power of the target optical signal received by the sub-ONU unit is lower than the first threshold, and/or, if the optical power of the target optical signal received by the sub-ONU unit is weakened and the optical power change value is greater than the first threshold Two thresholds, then the sub-ONU unit is used to send indication information to the sub-OLT unit;

The sub-OLT unit is configured to send the first optical signal according to the indication information.
The ONU according to claim 19, wherein a first optical splitter is connected between the ONU and the main OLT, a first port of the first optical splitter is connected to the main OLT, and the first optical splitter is connected to the main OLT. The second port of an optical splitter is connected to the sub-OLT unit, the third port of the first optical splitter is connected to the sub-ONU unit, and the fourth port of the first optical splitter is connected to the third port of the second optical splitter One port is connected to the second ONU, and the second port of the second optical splitter is connected to the second ONU.
The ONU according to claim 20, wherein the first port of the first optical splitter is used for inputting the target optical signal, and the third port of the first optical splitter is used for sending the optical signal to the sub-ONU unit outputting the target optical signal, and the fourth port of the first optical splitter is used to output the target optical signal to the second ONU;

If the optical power of the target optical signal received by the sub-ONU unit is lower than the first threshold, and/or, if the optical power of the target optical signal received by the sub-ONU unit is weakened and the optical power change value is greater than the first threshold Two thresholds, the second port of the first optical splitter is used to input the first optical signal, and the third port of the first optical splitter is used to output the first optical signal to the sub-ONU unit, so The fourth port of the first optical splitter is used to output the first optical signal to the second ONU.
The ONU according to any one of claims 19 to 21, wherein before the sub-ONU unit is used to detect the target optical signal from the main OLT, the sub-ONU unit is further configured to receive the signal from the main OLT notification message;

If the sub-ONU unit cannot receive the target optical signal, the sub-ONU unit is configured to determine a first time period according to the notification message, and the indication information includes the first time period;

The sub-OLT unit is specifically configured to send the first optical signal in the first time period according to the indication information.
The ONU according to claim 22, wherein if the sub-ONU unit cannot detect the target optical signal, the sub-ONU unit is further configured to detect the first optical signal and the first optical signal from the third ONU Two optical signals, the third ONU is used to send the second optical signal in a second time period, wherein the first time period and the second time period do not overlap, and the notification message is also used to indicate the first time period. the total duration of the first period and the second period;

If the sub-ONU unit can only receive the first optical signal within the total duration, the sub-OLT unit continues to send the first optical signal.
The ONU according to claim 22, wherein if the sub-ONU unit cannot detect the target optical signal, the sub-ONU unit is further configured to detect the first optical signal and the first optical signal from the third ONU Two optical signals, the third ONU is configured to send the second optical signal in a second period, wherein there is an overlapping period between the first period and the second period;

If the sub-ONU unit can identify the first optical signal during the first period, the sub-OLT unit continues to send the first optical signal.
The ONU according to any one of claims 19 to 24, wherein the wavelength of the target optical signal is the same as the wavelength of the first optical signal.
The ONU according to any one of claims 19 to 25, wherein the target optical signal includes a target identifier of the main OLT, and the first optical signal includes a first identifier of the sub-OLT unit.
An optical line terminal OLT, characterized in that it includes a processor and an optical transceiver, the processor and the optical transceiver are connected to each other through a line, and the processor is configured to execute the method according to claim 18 .
The OLT of claim 27, wherein the OLT further comprises a memory, the processor calling program code in the memory for performing the method of claim 18.