An optical communications network and a communications node

Abstract

This application provides a communication node and an optical communication network, belonging to the field of optical communication technology. The communication node includes a light source module, a link splitting module, and an optical transceiver module. The light source module provides local oscillator light and signal light to the optical transceiver module; the link splitting module receives downlink signals from the optical fiber, splits the downlink signals into N sub-downlink signals, and sends one sub-downlink signal to the optical transceiver module and the next node respectively, where N is a positive integer greater than 1; the optical transceiver module, based on the local oscillator light, obtains a signal with a wavelength matching the local oscillator light from the received downlink signals; it also generates an uplink signal with a wavelength different from the downlink signal based on the signal light, and sends the uplink signal to the optical fiber through the link splitting module. The uplink signal and the received downlink signal are transmitted in the same optical fiber but in opposite directions, saving optical fiber costs and fiber sourcing costs.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to an optical communication network and a communication node. Background Technology

[0002] Optical communication networks currently carry massive amounts of data communication and are crucial infrastructure. An efficient and reliable network architecture is the cornerstone of ensuring network connectivity. For metropolitan area networks (MANs), fiber optic links span wide distances and need to carry various services, such as home broadband, mobile backhaul, and enterprise leased lines, thus requiring high link reliability. In real-world environments, factors such as road construction and natural disasters frequently cause fiber optic link interruptions. Therefore, MAN architecture design must consider how to maintain communication services after a fiber break.

[0003] Typically, metropolitan area networks (MANs) use a dual-fiber ring network architecture, connecting aggregation nodes and multiple leaf nodes to support link protection of the ring network. However, this approach suffers from high fiber optic costs and fiber sourcing costs. Summary of the Invention

[0004] This application provides a communication node and an optical communication network composed of the communication nodes, which has a simple structure and low cost.

[0005] In a first aspect, this application provides a communication node comprising a first light source module, a link splitting module, and a first optical transceiver module. The first light source module provides a first local oscillator light and a first signal light to the first optical transceiver module. The link splitting module receives a first downlink signal from an optical fiber, divides the first downlink signal into N first sub-downlink signals, and sends one first sub-downlink signal to the first optical transceiver module and the next node, respectively, where N is a positive integer greater than 1. The first optical transceiver module, based on the first local oscillator light, obtains a signal with a wavelength matching the wavelength of the first local oscillator light from the received first sub-downlink signals. It is also used to generate a first uplink signal with a wavelength different from the wavelength of the first downlink signal based on the first signal light, and sends the generated signal to the link splitting module. The first uplink signal is transmitted to the optical fiber through the link splitting module, wherein the first uplink signal and the first downlink signal are transmitted in the same optical fiber and in opposite directions. In this embodiment, the uplink signal and the downlink signal are transmitted through the same optical fiber, saving fiber sourcing costs, and the bidirectional transmission of a single fiber ensures strict equality of the uplink and downlink links, avoiding clock calibration problems caused by asymmetric uplink and downlink distances.

[0006] It should be understood that, with the wavelength of the local oscillator light as the center and the receiving bandwidth of the first optical transceiver module as the spectral width, the signal within this spectral range is the signal whose wavelength matches the wavelength of the first local oscillator light. The receiving bandwidth of the first optical transceiver module can be 20GHz, 40GHz, 60GHz, 80GHz, or even higher. If the receiving bandwidth is very wide, and the unnecessary subcarriers of this node are received along with the necessary subcarriers, the necessary subcarriers can be extracted from the received subcarriers in the electrical domain. This will not be elaborated further in this application.

[0007] In this embodiment, the communication node can be used as a leaf node in the optical communication network to communicate with the aggregation node in the optical communication network, that is, to receive downlink signals from the aggregation node and send uplink signals to the aggregation node.

[0008] In conjunction with the first aspect, in a first possible implementation of the first aspect, the wavelengths of the first local oscillator light and the first signal light are different, which can ensure at the optical layer that the wavelength of the first uplink signal generated based on the first signal light is different from the wavelength of the first downlink signal.

[0009] In conjunction with the above implementation methods, in the second possible implementation of the first aspect, the first optical transceiver module receives the first downlink signal using coherent reception, wherein the first downlink signal is a multi-subcarrier signal. Since the specific wavelength of reception is achieved by coherent reception in the first optical transceiver module, it can be implemented at the subcarrier granularity, resulting in small granularity and high flexibility.

[0010] In conjunction with the above implementation methods, in the third possible implementation of the first aspect, the link splitting module includes a first combining unit, a first splitting unit, and a second combining unit. The first combining unit is used to receive the first downlink signal from the optical fiber and send the first downlink signal to the first splitting unit. The first splitting unit divides the first downlink signal into N first sub-downlink signals and sends one first sub-downlink signal to the first optical transceiver module and the second multiplexer, respectively. It is also used to receive the first uplink signal and send the first uplink signal to the first combining unit. The first combining unit sends the first uplink signal to the optical fiber, and the second combining unit sends one received first sub-downlink signal to the optical fiber. In this embodiment, the communication node does not need to use devices such as OADM, resulting in lower device costs.

[0011] In conjunction with the third possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the link splitting module further includes an optical switch and a second splitting unit; the optical switch is used to switch the optical path between the first optical transceiver module and the first splitting unit and between the first optical transceiver module and the second splitting unit; the second combining unit is further used to receive a second downlink signal from the optical fiber and send the received downlink signal to the second splitting unit; the second splitting unit is used to divide the received downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the optical switch and the first combining unit respectively; send the uplink signal sent by the optical switch to the second combining unit; send one received second sub-downlink signal to the optical fiber through the first combining unit; send the received uplink signal to the optical fiber through the second combining unit, wherein the uplink signal sent by the second combining unit and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

[0012] Furthermore, the optical switch is specifically used to: connect the optical path between the first optical transceiver module and the second splitting unit when the link between the first combining unit and the aggregation node fails; and connect the optical path between the first optical transceiver module and the first splitting unit when the link between the second combining unit and the aggregation node fails.

[0013] In this embodiment of the application, the use of optical switches reduces the number of optical transceiver modules and light source modules in the communication node, thereby reducing costs. Furthermore, in the event of a link failure, the communication node can still communicate normally with the aggregation node on the side where the failure did not occur, with the failure point as the dividing point, thus maintaining the connection and enabling protection switching functionality.

[0014] In conjunction with the first aspect and the first or second possible implementation, in the fifth possible implementation of the first aspect, the communication node further includes a second light source module and a second optical transceiver module; the second light source module is used to provide the second local oscillator light and the second signal light to the second optical transceiver module; the link splitting module is further used to receive the second downlink signal from the optical fiber, divide the second downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the second optical transceiver module and the next node respectively, where M is a positive integer greater than 1; the second optical transceiver module is used to obtain a signal with a wavelength matching the wavelength of the second local oscillator light from the received second sub-downlink signals based on the second local oscillator light; it is also used to generate a second uplink signal with a wavelength different from the second downlink signal based on the second signal light, and send the generated signal to the link splitting module; the link splitting module is further used to send the second uplink signal to the optical fiber, wherein the second uplink signal and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

[0015] Optionally, the wavelength of the second downlink signal is different from that of the first downlink signal. Further, the wavelength of the second local oscillator is different from that of the first local oscillator; if the receiving bandwidth of the second optical transceiver module is large enough, the wavelengths of the second local oscillator and the first local oscillator can also be the same, as long as the receiving bandwidth of the second optical transceiver module can cover the subcarriers required by this node in the second downlink signal with the wavelength of the second local oscillator as the center.

[0016] In this embodiment, when a link fails, the communication node can maintain normal communication with the aggregation node on the non-faulty side, using the fault point as a dividing point. For example, if the communication node cannot receive the first downlink signal from aggregation node 1 due to a link failure, it can communicate with aggregation node 2 on the other side of the fault point to receive / send the second downlink signal / second uplink signal, ensuring service continuity. Furthermore, the uplink and downlink signals are transmitted through the same optical fiber, saving on fiber and fiber sourcing costs, and ensuring strict equality between uplink and downlink distances, avoiding clock calibration problems caused by asymmetric uplink and downlink distances.

[0017] In conjunction with the first aspect and the first or second possible implementation of the first aspect, in the sixth possible implementation of the first aspect, the communication node further includes an optical switch and a second optical transceiver module; the optical switch is used to switch the optical path between the first light source module and the first optical transceiver module and between the first light source module and the second optical transceiver module; the first light source module is also used to provide a second local oscillator light and a second signal light to the second optical transceiver module; the link splitting module is also used to receive a second downlink signal from the optical fiber, divide the second downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the second optical transceiver module and the next node respectively, where M is a positive integer greater than 1; the second optical transceiver module is used to obtain a signal with a wavelength matching the wavelength of the second local oscillator light from the received second sub-downlink signals based on the second local oscillator light; it is also used to generate a second uplink signal with a wavelength different from the second downlink signal based on the second signal light, and send the generated signal to the link splitting module; the link splitting module is also used to send the second uplink signal to the optical fiber, wherein the second uplink signal and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

[0018] Furthermore, in this embodiment, the optical switch is specifically used to: connect the optical path between the first light source module and the second optical transceiver module when the link splitter module cannot receive the first downlink signal; and connect the optical path between the first light source module and the first optical transceiver module when the link splitter module cannot receive the second downlink signal. By applying the optical switch, the number of light source modules in the communication node is reduced, costs are lowered, and the protection switching function can be retained.

[0019] In conjunction with the first aspect and the fifth or sixth possible implementation of the first aspect, in the seventh possible implementation of the first aspect, the link splitting module includes a first combining unit, a first splitting unit, a second splitting unit, and a second combining unit; the first combining unit is used to receive the first downlink signal from the optical fiber and send the first downlink signal to the first splitting unit; the first splitting unit divides the first downlink signal into N first sub-downlink signals and sends one first sub-downlink signal to the first optical transceiver module and the second combining unit respectively; it is also used to receive the first uplink signal and send the first uplink signal to the first combining unit; The second combining unit is used to receive the second downlink signal from the optical fiber and send the second downlink signal to the second splitting unit; the second splitting unit divides the second downlink signal into M second sub-downlink signals and sends one second sub-downlink signal to the second optical transceiver module and the first combining unit respectively; it is also used to receive the second uplink signal and send the second uplink signal to the second combining unit; the first combining unit is used to send the first uplink signal and the received second sub-downlink signal to the optical fiber; the second combining unit is used to send the second uplink signal and the received first sub-downlink signal to the optical fiber. This link splitting module provided in this embodiment includes different splitting units, allowing the first splitting unit and the second splitting unit to use different splitting ratios to optimize the downlink power and pass-through power of the downlink signals from the two aggregation nodes.

[0020] In combination with any of the first aspect and above possible implementations, in the eighth possible implementation of the first aspect, the wavelengths of the signals output by the link splitting module to the optical fiber are different, so that the signals transmitted in the same optical fiber will not interfere with each other, thus ensuring signal quality.

[0021] In conjunction with the fourth or seventh possible implementation of the first aspect, in the ninth possible implementation of the first aspect, the wavelength difference between the two signals output by the first combining unit is not greater than the gain spectral width of the amplifier; and / or, the wavelength difference between the two signals output by the second combining unit is not greater than the gain spectral width of the amplifier, so that signals in the same direction can be amplified by the same optical amplifier, and the structure is simpler.

[0022] Optionally, the first splitting unit includes a first coupler and a first uplink / downlink splitting module. A single port on one side of the first coupler is connected to the first multiplexer, and two ports on the other side are respectively connected to the second multiplexer and the first uplink / downlink splitting module. The first uplink / downlink splitting module is used to transmit downlink signals from the first coupler and output uplink signals to the first coupler. The second splitting unit includes a second coupler and a second uplink / downlink splitting module. A single port on one side of the second coupler is connected to the second multiplexer, and two ports on the other side are respectively connected to the first multiplexer and the second uplink / downlink splitting module. The second uplink / downlink splitting module is used to transmit downlink signals from the second coupler and output uplink signals to the second coupler.

[0023] Optionally, the first splitting unit is a 1×3 coupler, with a single port on one side connected to the first combining unit, and three ports on the other side connected to the second combining unit, the receiving port of the first optical transceiver module, and the transmitting port of the first optical transceiver module, respectively. Further, the first uplink / downlink splitting module and the second uplink / downlink splitting module can be any of a coupler, a circulator, or a multiplexer. The first combining unit and the second combining unit can be any of a multiplexer or a coupler. The communication node in this embodiment can be implemented using inexpensive couplers, thin-film filters, etc., without the need for devices such as OADMs based on dense filtering, resulting in a simple structure and low cost.

[0024] In combination with the first aspect and any of the above possible implementations, the light source module (the first light source module and / or the second light source module) may include two light sources to generate local oscillator light and signal light respectively; or it may be a wavelength-tunable light source that generates local oscillator light and signal light in a time-division manner; wherein, the light source may be a laser or the like.

[0025] In one possible implementation, both the first downlink signal and the second downlink signal are multi-subcarrier signals, while the first uplink signal and the second uplink signal can be single-subcarrier signals or multi-subcarrier signals. This allows different communication nodes to use different subcarriers, enabling each node to accurately receive its own data.

[0026] Secondly, a communication node is provided, comprising a splitting module, a light source module, and an optical transceiver module; the splitting module is used to receive uplink signals from an optical fiber and transmit the uplink signals to the optical transceiver module; the light source module is used to provide local oscillator light and signal light to the optical transceiver module; the optical transceiver module is used to receive the uplink signals transmitted by the splitting module based on the local oscillator light; and is also used to generate downlink signals based on the signal light and transmit the downlink signals to the splitting module, wherein the receiving bandwidth of the optical transceiver module covers the wavelength range of the uplink signals centered on the local oscillator light wavelength; the splitting module is used to transmit the downlink signals received from the optical transceiver module to the optical fiber, wherein the uplink signals and the downlink signals are transmitted in the same optical fiber and in opposite directions.

[0027] Optionally, the splitter module can be any one of a coupler, a multiplexer, or a circulator. The light source module can include two light sources to generate local oscillator light and signal light respectively; it can also be a wavelength-tunable light source to generate local oscillator light and signal light in a time-division multiplexing manner; wherein, the light source can be a semiconductor laser, etc.

[0028] It should be understood that the communication node in this aspect can serve as a convergence node in an optical communication network, used to communicate with the leaf nodes in the optical communication network, that is, to receive uplink signals from the leaf nodes and send downlink signals to the leaf nodes.

[0029] In this embodiment, the uplink and downlink signals are transmitted through the same optical fiber, which saves fiber sourcing costs. Furthermore, the bidirectional nature of the single fiber ensures that the uplink and downlink are strictly equal, avoiding clock calibration problems caused by asymmetric uplink and downlink distances.

[0030] In conjunction with the second aspect, in the first possible implementation of the second aspect, the first optical transceiver module receives the first downlink signal using coherent reception, wherein the first downlink signal is a multi-subcarrier signal. Since the specific wavelength of reception is implemented by coherent reception in the first optical transceiver module, it can be at the subcarrier granularity, which is small and highly flexible.

[0031] Thirdly, an optical communication network is provided, characterized in that the optical communication network includes a first aggregation node, a plurality of leaf nodes, and a second aggregation node; the first aggregation node, the plurality of leaf nodes, and the second aggregation node are connected in series via optical fibers, wherein the first aggregation node and the second aggregation node are the start and end points of the series connection, respectively; wherein the first aggregation node and the second aggregation node are communication nodes according to the second aspect and any possible implementation thereof, and the leaf nodes are communication nodes according to the first aspect and any possible implementation thereof.

[0032] In the optical communication network architecture provided in this application embodiment, the connection between two aggregation nodes can be realized based on a single optical fiber, saving optical fiber costs and fiber sourcing costs, and the reliability of the link can still be maintained after the fiber is broken; in addition, the bidirectional nature of the single fiber ensures that the uplink and downlink are strictly equal, which can avoid clock calibration problems caused by the asymmetry of the uplink and downlink distances.

[0033] In conjunction with the third aspect, in the first possible implementation of the third aspect, the uplink signal wavelengths output by the multiple leaf nodes to the first aggregation node are different, and the uplink signal wavelengths output by the multiple leaf nodes to the second aggregation node are also different. In this application, the uplink signal output by each leaf node is one or more subcarrier signals, which ultimately constitute a multi-subcarrier signal sent to the corresponding aggregation node. This allows a large number of leaf nodes to use low-bandwidth devices, thereby saving system costs.

[0034] In conjunction with the third aspect and any possible implementation thereof, in the second possible implementation of the third aspect, the optical communication network further includes a bidirectional amplification module located between any two nodes for bidirectional amplification of the signal transmitted in the optical fiber.

[0035] In conjunction with the second possible implementation of the third aspect, in the third possible implementation of the third aspect, the bidirectional amplification module includes a third combining unit, a first optical amplifier, a second optical amplifier, and a fourth combining unit. A first optical signal is sent to the first optical amplifier via the third combining unit, amplified by the first optical amplifier, and then sent to the optical fiber via the fourth combining unit. A second optical signal is sent to the second optical amplifier via the fourth combining unit, amplified by the second optical amplifier, and then sent to the optical fiber via the third combining unit. The first and second optical signals propagate in opposite directions on the optical fiber. Signals within the gain spectral width of the optical amplifier can be amplified together, i.e., multi-subcarrier signals and multiple signals with similar wavelengths. As long as the wavelength is within the gain spectral width of the optical amplifier, optical amplification can be achieved using the structure of this embodiment, resulting in a relatively simple structure.

[0036] In conjunction with the third possible implementation of the third aspect, in the fourth possible implementation of the third aspect, the third combining unit and the fourth combining unit are any one of a multiplexer, a coupler, and a circulator, and the device cost is low.

[0037] Fourthly, this application provides a signal transmission and reception method applicable to leaf nodes in an optical communication network. The method includes: generating a first local oscillator light and a first signal light; receiving a first downlink signal from an optical fiber in the optical communication network; dividing the first downlink signal into N first sub-downlink signals; sending one of the first sub-downlink signals to a next node, which may be a leaf node or a aggregation node, where N is a positive integer greater than 1; then, based on the first local oscillator light, obtaining a signal with a wavelength matching the wavelength of the first local oscillator light from the received first sub-downlink signals; further comprising generating a first uplink signal with a wavelength different from the wavelength of the first downlink signal based on the first signal light; and then sending the first uplink signal to the optical fiber, wherein the first uplink signal and the first downlink signal are transmitted in the same optical fiber and in opposite directions.

[0038] Fifthly, this application provides a signal transceiver method applicable to aggregation nodes in an optical communication network. The method includes: generating local oscillator light and signal light; receiving an uplink signal from an optical fiber; receiving the uplink signal based on the local oscillator light; further comprising generating a downlink signal based on the signal light, wherein the received bandwidth is centered on the wavelength of the local oscillator light and covers the wavelength range of the uplink signal; and transmitting the downlink signal to the optical fiber, wherein the uplink signal and the downlink signal are transmitted in the same optical fiber and in opposite directions.

[0039] Sixthly, this application provides a signal transceiver method applicable to an optical communication network, the optical communication network including a first aggregation node, a plurality of leaf nodes, and a second aggregation node; the first aggregation node, the plurality of leaf nodes, and the second aggregation node are connected in series via optical fibers, the first aggregation node and the second aggregation node being the start and end points of the series connection, respectively, wherein the first aggregation node and the second aggregation node perform the signal transceiver method as described in the fifth aspect, and the leaf nodes perform the signal transceiver method as described in the fourth aspect.

[0040] In the optical communication network architecture provided in this application embodiment, a single optical fiber can connect two aggregation nodes, saving fiber and fiber sourcing costs, and maintaining link reliability even after fiber breakage. Furthermore, the bidirectional nature of the single fiber ensures strict equality between uplink and downlink, avoiding clock calibration issues caused by asymmetric uplink and downlink distances. Moreover, the optical communication network adopts a point-to-multipoint architecture, allowing for different bandwidth requirements between aggregation nodes and leaf nodes. High-bandwidth devices can be used in a few aggregation nodes, while low-bandwidth devices can be used in most leaf nodes, thus saving system costs. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a traditional metropolitan area network architecture;

[0042] Figure 2 A schematic diagram of an optical communication network provided for an exemplary embodiment of this application;

[0043] Figure 3 This is a schematic diagram of a multi-subcarrier signal;

[0044] Figure 4(a) is a schematic diagram of the structure of a bidirectional amplification module provided in an embodiment of this application;

[0045] Figure 4(b) is a schematic diagram of the structure of a bidirectional amplification module provided in another embodiment of this application;

[0046] Figure 5 This is a schematic diagram showing the relative wavelengths of the uplink and downlink signals at two aggregation nodes.

[0047] Figure 6 This is a schematic diagram of the structure of the aggregation node provided in an embodiment of this application;

[0048] Figure 7(a) is a schematic diagram of the structure of a convergence node provided in another embodiment of this application;

[0049] Figure 7(b) is a schematic diagram of the structure of a convergence node provided in another embodiment of this application;

[0050] Figure 7(c) is a schematic diagram of the structure of a convergence node provided in another embodiment of this application;

[0051] Figure 8 A schematic diagram of the structure of a convergence node is provided in another embodiment of this application;

[0052] Figure 9 This is a schematic diagram of the structure of a leaf node provided in an embodiment of this application;

[0053] Figure 10 This is a schematic diagram of the structure of a link splitting module provided in an embodiment of this application;

[0054] Figure 11 This is a schematic diagram of the structure of a splitter unit provided in an embodiment of this application;

[0055] Figure 12 This is a schematic diagram of the structure of a leaf node provided in another embodiment of this application;

[0056] Figure 13 A schematic diagram of a link splitting module provided in another embodiment of this application;

[0057] Figure 14 This is a schematic diagram of the structure of a leaf node provided in another embodiment of this application;

[0058] Figure 15A schematic diagram of the structure of a link splitting module provided in another embodiment of this application;

[0059] Figure 16 This is a schematic diagram of the structure of a leaf node provided in another embodiment of this application;

[0060] Figure 17 This is a schematic diagram of the structure of a leaf node provided in another embodiment of this application. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0062] In network transmission architecture, the metropolitan area network (MAN) is located at the intersection of the backbone network and the access network, and it is a network with a relatively complex application environment in communications. Various types of service data with different needs are carried directly or indirectly through the MAN, and are aggregated, distributed, and enter / exit the backbone network within the MAN. Figure 1 The diagram illustrates a traditional metropolitan area network (MAN) architecture, which can be broadly divided into three parts: the metropolitan access layer, the metropolitan aggregation layer, and the metropolitan core layer. Typically, the metropolitan access and aggregation layers employ a dual-fiber ring architecture. This ring architecture includes two aggregation nodes and multiple leaf nodes, with the two aggregation nodes serving as the starting and ending points, respectively. Multiple leaf nodes are connected in series via two optical fibers to form a ring structure. The aggregation nodes transmit / receive wavelength division multiplexed signals containing multiple wavelengths, while the leaf nodes transmit / receive signals of several wavelengths via optical add-drop multiplexers (OADMs). During normal operation, each leaf node can establish connections with two aggregation nodes, enabling uplink and downlink communication via two optical fibers. In the event of a fiber breakage, all leaf nodes can maintain communication with one of the aggregation nodes, serving as a protection failover mechanism.

[0063] It should be understood that Figure 1 This is merely an exemplary architecture for a metropolitan area network (MAN). Each layer may have multiple ring architectures. For example, taking the metropolitan access layer as an example, the ring architecture shared by the metropolitan aggregation layer (…) Figure 1 Nodes 1 and 2 in the above context are aggregation nodes in the ring architecture of the metropolitan area access layer. This means that nodes connected to the next higher-level ring architecture are aggregation nodes. These two aggregation nodes can also serve as aggregation nodes for other ring architectures. In other words, multiple ring architectures can exist in the metropolitan area access layer, with leaf nodes in each ring architecture responsible for communication with base stations, office buildings, and residents. Similarly, multiple ring architectures also exist in the metropolitan area aggregation layer. In this case, nodes 1 and 2 are leaf nodes in the metropolitan area aggregation layer, while the two nodes connected to the next higher-level ring architecture (e.g., ...) are aggregation nodes. Figure 1Nodes 3 and 4 in the diagram are the aggregation nodes of this level of the ring architecture. Typically, nodes like 1 and 2, which are located in a two-level ring architecture and serve as the aggregation node and leaf node respectively, can have two sets of devices stored in the node, which can communicate with each other.

[0064] This application provides an optical communication network comprising two aggregation nodes, multiple leaf nodes, and optical fibers. The two aggregation nodes serve as the starting and ending points, respectively, and the multiple leaf nodes are connected in series via a single optical fiber to form a ring network architecture. This architecture can be applied in metropolitan area networks (MANs) and can reduce fiber optic costs and fiber sourcing costs. Alternatively, the optical communication network can also consist of only one aggregation node, which can serve as both the starting and ending point to form a ring network architecture. Furthermore, the two aggregation nodes can be located in different equipment rooms. If one equipment room experiences a power outage or other issues, the aggregation node in the other equipment room can provide protection, resulting in higher network stability.

[0065] The optical communication network provided in the embodiments of this application is described below. Figure 2 A schematic diagram of an optical communication network is provided. The optical communication network includes two aggregation nodes and multiple leaf nodes. The aggregation nodes can also be referred to as central office nodes, central sites, central offices, or master nodes, etc., and the leaf nodes can also be referred to as leaf sites, access sites, or slave nodes, etc. The number of leaf nodes is not limited in this embodiment. There are two communication methods when the aggregation nodes communicate with the leaf nodes: one is time division multiple access (TDMA), and the other is frequency division multiple access (FDMA).

[0066] Time Division Multiple Access (TDMA) refers to a mechanism where each leaf node transmits data to the sink node using the same frequency band at different time periods. In TDMA, each leaf node is configured with a receive time period and a transmit time period (e.g., the sink node broadcasts the time periods of each leaf node, or the user configures the time periods within the leaf nodes themselves). Although each leaf node can receive downlink signals transmitted by the sink node, if the signal is not received within its corresponding time period, it will discard the received downlink signal and only send uplink signals to the sink node within its own corresponding time period.

[0067] Frequency Division Multiple Access (FDMA) refers to a method where each leaf node uses a different frequency band to transmit data. In FDMA, the sink node employs multi-carrier modulation technology, modulating data onto a single wavelength of light to obtain multiple subcarrier signals for that single wavelength. Different subcarrier signals correspond to different leaf nodes. Each leaf node is configured with a corresponding subcarrier wavelength. After receiving the multiple subcarrier signals transmitted by the sink node, each leaf node uses its corresponding wavelength of light as its local oscillator to coherently receive the subcarrier signal of its own wavelength from the multiple subcarrier signals. The wavelength corresponding to a leaf node is the center wavelength of the subcarrier signal it wants to receive. Furthermore, each leaf node uses its own corresponding wavelength of light to transmit the subcarrier signal to the sink node. It should be noted that single-wavelength light refers to light with a single wavelength value, each subcarrier signal corresponds to one subcarrier, and different subcarrier signals correspond to different subcarriers, each with a different center wavelength. The following description uses FDMA as an example of communication methods.

[0068] Aggregation node 1 transmits a downlink multi-subcarrier signal with a center wavelength of λ1, the number of subcarriers being K1, and the center wavelength of the subcarriers being λ. 1-1 , λ 1-2 , …, λ 1-K1 The leaf nodes will receive downlink multi-subcarrier signals with a center wavelength of λ1. They will extract their own subcarrier portion from the downlink multi-subcarrier signal through coherent reception. Each leaf node can correspond to one or more subcarrier signals; this application does not limit this. The leaf nodes will send subcarrier signals with a center wavelength near λ2. These signals will be aggregated step-by-step by the link splitting module into an uplink multi-subcarrier signal with a center wavelength of λ2, which will be uniformly received by the aggregation node 1. The number of uplink subcarriers is K2, and the center wavelengths of the subcarriers are λ1, λ2 ... 2-1 , λ 2-2 , …, λ 2-K2 .

[0069] Aggregation node 2 transmits a downlink multi-subcarrier signal with a center wavelength of λ3. The number of subcarriers is K3, and the center wavelength of the subcarriers is λ. 3-1 , λ 3-2 , …, λ 3-K3 The leaf nodes also receive downlink multi-subcarrier signals with a center wavelength of λ3. They extract their own subcarrier portion from the downlink multi-subcarrier signal through coherent reception. Each leaf node can correspond to one or more subcarrier signals; this application does not limit this. The leaf nodes also transmit subcarrier signals with a center wavelength near λ4. These are aggregated step-by-step by the link splitting module into an uplink multi-subcarrier signal with a center wavelength of λ4, which is then received by the aggregation node 2. The number of uplink subcarriers is K4, and the center wavelengths of the subcarriers are λ... 4-1 , λ4-1 , …, λ 4-K4 Among them, the spectra of the multi-subcarrier signals with center wavelengths of λ1, λ2, λ3, and λ4 do not overlap and can be transmitted normally in the same optical fiber without affecting each other. Taking the multi-subcarrier signal with center wavelength λ1 as an example, its signal characteristics are as follows: Figure 3 As shown.

[0070] In an optical communication network, each node can upload the same number of subcarriers with different wavelengths. Taking communication between a leaf node and sink node 1 as an example, there are K2 leaf nodes, each uploading one subcarrier; or (K2) / 2 leaf nodes, each uploading two subcarriers, ultimately forming an uplink multi-subcarrier signal with a center wavelength of λ2 and the number of subcarriers being K2; alternatively, some leaf nodes may upload different numbers of subcarriers, ultimately forming an uplink multi-subcarrier signal with a center wavelength of λ2 and the number of subcarriers being K2. The situation for communication between a leaf node and sink node 2 is similar and will not be described further in this application.

[0071] During normal operation, aggregation node 1 can communicate normally with all leaf nodes, and aggregation node 2 can also communicate normally with all leaf nodes. When the link is interrupted, the leaf nodes on the left side can still communicate normally with aggregation node 1, and the leaf nodes on the right side can still communicate normally with aggregation node 2, thus maintaining the connection and preventing a complete service interruption.

[0072] Optionally, the optical communication network also includes a bidirectional amplification module located between any two nodes. This module can be located between a sink node and a leaf node, or between two leaf nodes, and is used to amplify signals transmitted bidirectionally in the optical fiber. The bidirectional amplification module includes a combining unit 1, an optical amplifier 1, an optical amplifier 2, and a combining unit 2, as shown in Figure 4(a). The sink node 1 sends a downlink multi-subcarrier signal with a center wavelength of λ1 to the optical amplifier 1 through the combining unit 1. After amplification by the optical amplifier 1, the amplified signal is sent to the optical fiber through the combining unit 2. The sink node 2 sends a downlink multi-subcarrier signal with a center wavelength of λ3 to the optical amplifier 2 through the combining unit 2. After amplification by the optical amplifier 2, the amplified signal is sent to the optical fiber through the combining unit 1. The transmission directions of the two downlink signals on the optical fiber are opposite. The combining unit can be a multiplexer, a coupler, or a circulator, which is not limited in this application. Similarly, the subcarrier signals with a center wavelength near λ2 sent from the leaf node to the aggregation node 1, if passed through the bidirectional amplification module, will be similar to the downlink multi-subcarrier signals sent by the aggregation node 2. After being amplified by the optical amplifier 2, they will be sent to the optical fiber. The subcarrier signals with a center wavelength near λ4 sent from the leaf node to the aggregation node 2, if passed through the bidirectional amplification module, will be similar to the downlink multi-subcarrier signals sent by the aggregation node 1. After being amplified by the optical amplifier 1, they will be sent to the optical fiber. The transmission directions of the two uplink signals on the optical fiber are also opposite.

[0073] It should be noted that the wavelength λ1 of the downlink signal of aggregation node 1 is close to the wavelength λ4 of the uplink signal of aggregation node 2, and the wavelength λ2 of the uplink signal of aggregation node 1 is close to the wavelength λ3 of the downlink signal of aggregation node 2, such as... Figure 5 As shown. Optionally, the wavelength difference between λ1 and λ4 is not greater than the gain spectral width of the amplifier; and / or, the wavelength difference between λ2 and λ3 is not greater than the gain spectral width of the amplifier. Moreover, when the combining unit is a multiplexer, wavelengths λ1 and λ4 are within the passband of port 1 of combining unit 1 and port 1 of combining unit 2, and wavelengths λ2 and λ3 are within the passband of port 2 of combining unit 1 and port 2 of combining unit 2. Note that the wavelength symbols mentioned here can refer to multi-subcarrier signals, that is, the wavelength of any one of the subcarriers in the downlink multi-subcarrier signal of aggregation node 1 and the uplink multi-subcarrier signal of aggregation node 2 is within the gain spectral width of amplifier 1; the wavelength of any one of the subcarriers in the uplink multi-subcarrier signal of aggregation node 1 and the downlink multi-subcarrier signal of aggregation node 2 is within the gain spectral width of amplifier 2.

[0074] Furthermore, aggregation nodes 1 and 2 can transmit more downlink multi-subcarrier signals with different center wavelengths, and leaf nodes can also transmit more uplink multi-subcarrier signals with different center wavelengths, thereby increasing system capacity. The bidirectional amplification module can also support signal amplification of more wavelengths. For example, it can use optical amplifiers that can support a wider gain spectral width, or combiner unit 1 and combiner unit 2 can be interconnected through more ports, with more optical amplifiers connected in between. Assuming that aggregation node 1 also transmits downlink multi-subcarrier signals with a wavelength of λ5, aggregation node 2 also transmits downlink multi-subcarrier signals with a wavelength of λ7, and multiple leaf nodes also transmit uplink multi-subcarrier signals with wavelengths of λ6 and λ8 to aggregation node 1 and aggregation node 2 respectively, then an exemplary structure of the bidirectional amplification module is shown in Figure 4(b), which is not limited in this application.

[0075] In the optical communication network architecture provided in this application embodiment, a single optical fiber can be used to connect two aggregation nodes, saving fiber and fiber sourcing costs, and maintaining link reliability even after fiber breakage. Furthermore, the bidirectional nature of the single fiber ensures strict equality between uplink and downlink, avoiding clock calibration problems caused by asymmetric uplink and downlink distances. The bandwidth requirements of the aggregation nodes and leaf nodes can also differ; high-bandwidth devices can be used in a few aggregation nodes, while low-bandwidth devices can be used in most leaf nodes, thereby saving system costs.

[0076] Figure 6 This is a schematic diagram of a communication node, which can serve as a convergence node in an optical communication network. The following description uses it as an example. The convergence node includes a splitter module 01, a light source module 02, and an optical transceiver module 03. The splitter module 01 receives uplink signals from various leaf nodes via optical fibers and transmits these uplink signals to the optical transceiver module 03. The light source module 02 provides local oscillator light and signal light to the optical transceiver module 03. The optical transceiver module 03 receives the uplink signal based on the local oscillator light, using coherent reception. The receiving bandwidth of the optical transceiver module 03 is centered on the wavelength of the local oscillator light and can cover the wavelength range of the uplink signal. A downlink signal is generated based on the signal light and sent to the splitter module 01, which then transmits the downlink signal back to the optical fiber. The downlink signal transmitted by the splitter module 03 and the received uplink signal are transmitted in the same optical fiber, but in opposite directions.

[0077] Specifically, the optical transceiver module includes a receiver and a transmitter. The light source module 02 sends local oscillator light to the receiver for receiving the uplink signal; and sends signal light to the transmitter for generating a downlink signal. The wavelength range that the receiver can receive is the range centered on the wavelength of the local oscillator light and with the receiver bandwidth as the spectral width. The receiver bandwidth can be 20GHz, 40GHz, 60GHz, 80GHz, or even wider, as long as it can cover the wavelength range of the uplink signal. This application does not impose any limitations. Taking the uplink signal as an example, which is a multi-subcarrier signal with center wavelengths of 1549.8nm, 1549.9nm, 1550nm, 1550.1nm, and 1550.2nm respectively, and assuming the wavelength of the local oscillator is 1550nm, since the wavelength range of the multi-subcarrier signal is from 1549.8nm to 1550.2nm, corresponding to a frequency range of about 50GHz, then with the wavelength of the local oscillator as the center, the receiver bandwidth only needs to exceed 50GHz to cover the wavelengths of all subcarriers, ensuring that each subcarrier signal in the uplink signal can be received.

[0078] In this embodiment, the splitter module 01 can be any one of a coupler, a multiplexer, or a circulator; the light source module 02 can include two light sources to generate local oscillator light and signal light respectively; or it can be a wavelength-tunable light source to generate local oscillator light and signal light in a time-division manner; wherein, the light source can be a laser, etc., and the light source modules in subsequent embodiments are similar, and will not be described again in this application.

[0079] Furthermore, the aggregation node can be expanded to support uplink and downlink signal transmission and reception of more wavelengths. For example, it can be expanded by using 1×n port couplers or multiplexers, or by cascading multiple couplers, multiple multiplexers, couplers and multiplexers, couplers and circulators, or multiplexers and circulators. Its main function is to separate multiple downlink signals from multiple uplink signals, ensuring that multiple transceiver modules can receive and send different signals. Figures 7(a) to 7(c) Several possible expansion structures are given. The figure shows an example of expansion to two optical transceiver modules. Further expansion can be carried out in a similar manner, which will not be elaborated in this application.

[0080] It should be understood that when the effective bandwidth of the aggregation node has been fully utilized, the transceiver modules of the aggregation node can be increased in the above way, which is equivalent to increasing the total number of subcarriers for transmission and reception. This allows the aggregation node and each leaf node to receive and transmit more subcarriers, thereby achieving capacity expansion.

[0081] It should be noted that an optical network architecture can also include only one aggregation node, which is equivalent to integrating the functions of two aggregation nodes into a single aggregation node. In this case, the aggregation node serves as both the start and end point of the optical network architecture, capable of receiving different uplink signals from opposite directions in the optical fiber and sending downlink signals with different transmission directions into the optical fiber. An exemplary structure is shown below. Figure 8 As shown.

[0082] Figure 9 This is a schematic diagram of another type of communication node, which can be used as a leaf node in an optical communication network. The following description uses it as an example of a leaf node. See also... Figure 9 The leaf node includes a first light source module 04, a link splitting module 05, and a first optical transceiver module 06. The link splitting module 05 receives a first downlink signal from the optical fiber, splits the first downlink signal into N first sub-downlink signals, and sends one first sub-downlink signal to the first optical transceiver module 06 and the next node, respectively. N is a positive integer greater than 1. The information carried by the N first sub-downlink signals is consistent with that of the first downlink signal. The power of each signal in the N first sub-downlink signals is reduced compared to the power of the first downlink signal before entering the link splitting module 05, but no information is lost. Here, the first downlink signal can be a multi-subcarrier signal centered on a certain wavelength.

[0083] The first light source module 04 is used to provide the first local oscillator light and the first signal light to the first optical transceiver module 06. The first optical transceiver module 06, based on the first local oscillator light, obtains a signal whose wavelength matches the wavelength of the first local oscillator light from the received first sub-downlink signal. For example, if the wavelength of the first local oscillator light is λ2, the first optical transceiver module 06 can coherently receive signals centered on wavelength λ2 within the receiving bandwidth of the first optical transceiver module 06. The subcarrier signal in the downlink signal within the above range is the signal whose wavelength matches the wavelength of the first local oscillator light. The receiving bandwidth of the first optical transceiver module 06 can be 20GHz, 40GHz, 60GHz, 80GHz, or even higher, which is not limited in this application. Furthermore, the first optical transceiver module 06 generates a first uplink signal based on the first signal light, whose wavelength differs from that of the first downlink signal. This first uplink signal is then sent to the link splitting module 05, which transmits it to the optical fiber. The first uplink signal transmitted to the optical fiber and the first downlink signal received from the optical fiber are transmitted in the same optical fiber, but in opposite directions. Specifically, the first optical transceiver module 06 includes a first receiver and a first transmitter. The first light source module 04 transmits a first local oscillator light to the first receiver to receive the first downlink signal and transmits the first signal light to the first transmitter to generate the first uplink signal. The receiving bandwidth of the first optical transceiver module 06 is the same as the receiving bandwidth of the first receiver.

[0084] Optionally, the link splitting module 05 includes a first combining unit 051, a first splitting unit 052, and a second combining unit 053, with the following structure: Figure 10 As shown, the first combining unit 051 is used to receive the first downlink signal from the optical fiber, send the first downlink signal to the first splitting unit 052, and send the received first uplink signal to the optical fiber. Specifically, the first combining unit 051 can be a multiplexer or a coupler. Since the first downlink signal is a multi-subcarrier signal within a certain wavelength range, the multiplexer can output the first downlink signal through one port without splitting the first downlink signal into multiple lower-power signals, resulting in less loss.

[0085] The first splitting unit 052 divides the received first downlink signal into N first sub-downlink signals and sends one first sub-downlink signal to the first optical transceiver module 06 and the second combining unit 053 respectively; it is also used to receive the first uplink signal and send the first uplink signal to the first combining unit 051.

[0086] Specifically, the first splitting unit 052 includes a first coupler 0521 and a first uplink / downlink splitting module 0522, the structure of which is as follows: Figure 11 As shown, a single port on one side of the first coupler 0521 is connected to the first combining unit 051, and there are at least two ports on the other side, which are respectively connected to the second combining unit 053 and the first uplink / downlink splitter module 0522; the first uplink / downlink splitter module 0522 can be any of a coupler, a circulator, or a multiplexer, and is used to send downlink signals from the first coupler 0521 and output uplink signals to the first coupler 0521.

[0087] The second combining unit 053 can be a multiplexer or coupler, used to transmit one of the received first sub-downlink signals onto the optical fiber.

[0088] In this embodiment, the uplink and downlink signals are transmitted through the same optical fiber, saving fiber sourcing costs. The bidirectional nature of the single fiber ensures that the uplink and downlink are strictly equal, avoiding clock calibration problems caused by asymmetric uplink and downlink distances. In addition, the wave selection function is implemented by coherent reception in the module. Wave selection at the subcarrier level is small in granularity, highly flexible, and the leaf nodes do not require devices such as OADM, resulting in lower device costs.

[0089] Another embodiment of this application also provides a leaf node, which, in such a way... Figure 9 Based on the structure shown, it also includes a second light source module 07 and a second optical transceiver module 08, the specific structure of which is as follows: Figure 12As shown, the second light source module 07 provides the second local oscillator light and the second signal light to the second optical transceiver module 08. Optionally, the wavelength of the second local oscillator light may be different from that of the first local oscillator light emitted by the first light source module 04, and the wavelength of the second signal light may also be different from that of the first signal light emitted by the first light source module 04. That is, the wavelengths of the four lights are all different, which can prevent light of the same wavelength from being transmitted in the same optical fiber and causing crosstalk. It should be understood that if time division multiplexing is used, the two signal lights are not sent at the same time, then the wavelengths of the two signal lights can be the same, and correspondingly, the local oscillator light can also be the same.

[0090] The link splitting module 05 receives the first downlink signal from the optical fiber, divides it into N first sub-downlink signals, and sends one of these sub-downlink signals to the first optical transceiver module 06 and the next node, respectively, where N is a positive integer greater than 1. It also receives the second downlink signal from the optical fiber, divides it into M second sub-downlink signals, and sends one of these sub-downlink signals to the second optical transceiver module 08 and the next node, respectively, where M is a positive integer greater than 1. For the first downlink signal, the information carried by the N sub-downlink signals is identical; only the power of each of the N sub-downlink signals is reduced compared to the power of the first downlink signal before entering the link splitting module 05. No information is lost, meaning each sub-downlink signal carries the same information. The same applies to the second downlink signal; each sub-downlink signal carries the same information. The first downlink signal can be a multi-subcarrier signal centered on one wavelength, and the second downlink signal can be a multi-subcarrier signal centered on another wavelength.

[0091] The second optical transceiver module 08, based on the second local oscillator light, acquires a signal whose wavelength matches that of the second local oscillator light from the received second sub-downlink signal. For example, if the wavelength of the second local oscillator light is λ4, the second optical transceiver module 08 can coherently receive signals centered on wavelength λ4 within its receiving bandwidth. The subcarrier signals within this range in the second downlink signal are the signals whose wavelengths match those of the second local oscillator light. The receiving bandwidth of the second optical transceiver module 08 can be 20GHz, 40GHz, 60GHz, 80GHz, or even higher; this application does not limit this. Furthermore, the second optical transceiver module 08 also generates a second uplink signal based on the second signal light, with a wavelength different from that of the second downlink signal. This generated second uplink signal is sent to the link splitting module 05, which then transmits the second uplink signal to the optical fiber. The second uplink signal transmitted to the optical fiber and the second downlink signal received from the optical fiber are transmitted in the same optical fiber but in opposite directions. Specifically, the second optical transceiver module 08 includes a second receiver and a second transmitter. The second light source module 07 transmits a second local oscillator light to the second receiver for receiving the second downlink signal; and transmits a second signal light to the second transmitter for generating a second uplink signal. The receiving bandwidth of the second optical transceiver module 08 is the same as the receiving bandwidth of the second receiver. It should be understood that the optical transceiver modules in subsequent embodiments are similar, and will not be described in detail here.

[0092] Optionally, the structure of the link splitting module 05 is as follows: Figure 10 Based on the structure shown, a second branch unit 054 is also included, the specific structure of which is as follows: Figure 13 As shown, the functions and connections of the first combining unit 051 and the first splitting unit 052 are the same as in the previous embodiments, and will not be repeated in this embodiment. Assuming that in an optical communication network, the leaf node provided in this embodiment is connected to the aggregation node 1 through the first combining unit 051 and to the aggregation node 2 through the second combining unit 053, the second combining unit 053 receives the second downlink signal from the aggregation node 2 on the optical fiber and sends the second downlink signal to the second splitting unit 054. The second splitting unit 054 can divide the second downlink signal into M second sub-downlink signals, sending one second sub-downlink signal to the second optical transceiver module 08 and the first combining unit 051 respectively. It can also send the second uplink signal received from the second optical transceiver module 08 to the second combining unit 054, which then sends the second uplink signal to the optical fiber for communication with the aggregation node 2. The first combining unit 051 can be a multiplexer or a coupler, and the second combining unit 053 can also be a multiplexer or a coupler, where M is an integer greater than 1.

[0093] Similar to the first splitting unit 052, the second splitting unit 054 may also include a coupler and an uplink / downlink splitting module, with the same structure. Figure 11 As shown in this embodiment, the coupler and uplink / downlink splitter modules included in the second splitter unit 054 are referred to as the second coupler and the second uplink / downlink splitter module, respectively. A single port on one side of the second coupler is connected to the second combining unit 053, and at least two ports on the other side are connected to the first combining unit 051 and the second uplink / downlink splitter module, respectively. The second uplink / downlink splitter module can also be any one of a coupler, circulator, or multiplexer, used to transmit downlink signals from the second coupler and output uplink signals to the second coupler.

[0094] It should be noted that aggregation node 1 and aggregation node 2 can simultaneously transmit downlink signals with different wavelengths. The two optical transceiver modules in the leaf nodes can each receive the portion of the downlink signal corresponding to their own spectrum from the downlink signals from different aggregation nodes. Aggregation node 1 and aggregation node 2 can also transmit downlink signals in a time-division manner. In this case, the wavelengths of the downlink signals from the two aggregation nodes can be the same or different. Moreover, the two optical transceiver modules in the leaf nodes also operate in a time-division manner and do not need to work together. When a link failure occurs, the first optical transceiver module of the leaf node on one side communicates normally with aggregation node 1, and the second optical transceiver module of the leaf node on the other side communicates normally with aggregation node 2, thus maintaining the connection. Of course, when there are no links in the optical communication network, it is permissible for aggregation node 1 to communicate with multiple leaf nodes, with the first optical transceiver module 06 in the leaf node operating, or for aggregation node 2 to communicate with multiple leaf nodes, with the second optical transceiver module 08 in the leaf node operating; or for both optical transceiver modules to operate simultaneously, or for both optical transceiver modules to operate in a time-division manner. This application does not impose any limitations on this.

[0095] Furthermore, the leaf nodes provided in this embodiment can be expanded. For example, the leaf nodes can include more optical transceiver modules and light source modules, and can simultaneously transmit and receive multiple uplink and downlink signals. If the aggregation node can also support the transmission and reception of these signals, the system capacity can be expanded. Figure 14The diagram illustrates a possible expanded leaf node structure, which further includes a third light source module 09, a third optical transceiver module 10, a fourth light source module 11, and a fourth optical transceiver module 12. The link splitting module 05 also includes a third splitting unit 055 and a fourth splitting unit 056. In this configuration, the first combining unit 051 receives a third downlink signal from the optical fiber and sends it to the third splitting unit 055; the second combining unit 053 receives a fourth downlink signal from the optical fiber and sends it to the fourth splitting unit 056. The functions of the newly added light source module, optical transceiver module, and splitting unit are similar to those of the existing modules / units in the embodiments, and will not be described in detail here. However, the wavelengths of the uplink and downlink signals are different. Figure 14 The structure shown can simultaneously receive four downlink signals and transmit four uplink signals, thus improving system capacity. Even in the event of a fault, it can still ensure communication between two uplink and downlink signals and aggregation node 1 or aggregation node 2, maintaining a high system capacity while performing protection switching. Similarly, the first combining unit 051 and the second combining unit 053 can also branch out more paths and connect more branching units, enabling further system expansion.

[0096] In this embodiment, when a link failure occurs, the leaf node can maintain normal communication with the aggregation node on the non-faulty side, using the fault point as a dividing point, thus achieving the protection switching function. Uplink and downlink signals are transmitted through the same optical fiber, saving on fiber and fiber optic costs, and ensuring strict equality between uplink and downlink, avoiding clock calibration problems caused by asymmetrical uplink and downlink distances. Furthermore, the leaf node does not require devices such as OADMs, resulting in lower costs. In addition, the link splitting module 05 provided in this embodiment includes different splitting units, allowing different splitting ratios to optimize the downlink power and pass-through power of the downlink signals from aggregation node 1 and aggregation node 2.

[0097] Optionally, the structure of the link splitting module 05 is as follows: Figure 10 Based on the structure shown, it may also include a second branching unit 054 and a first optical switch 057, the structure of which is as follows: Figure 15 As shown, the first optical switch 057 is used to switch the optical path between the first optical transceiver module 06 and the first splitter unit 052 and the optical path between the first optical transceiver module 06 and the second splitter unit 054.

[0098] In an optical communication network, leaf nodes are connected to aggregation node 1 via a first combining unit 051 and to aggregation node 2 via a second combining unit 053. When a link failure occurs between the first combining unit 051 and aggregation node 1 (e.g., fiber optic cable breakage, connector failure, etc.), the first optical transceiver module 06 connects to the second splitting unit 054 via a first optical switch 057. The second splitting unit 054 and the second combining unit 053 receive a second downlink signal from aggregation node 2 via the optical fiber, and then send it to the first optical transceiver module 06 via the first optical switch 057. Furthermore, the first optical transceiver module 06 can also generate a second uplink signal based on the local oscillator light output from the first light source module 04. This uplink signal is sent to the second splitting unit 054 via the first optical switch 057, and then sent to the optical fiber via the second combining unit 053, thus communicating with aggregation node 2. The second uplink signal sent to the optical fiber and the second downlink signal received from the optical fiber are transmitted in the same optical fiber, but in opposite directions.

[0099] When the link between the second combining unit 054 and the aggregation node 2 fails, the first optical transceiver module 06 connects to the first splitting unit 052 through the first optical switch 057. The first splitting unit 052 and the first combining unit 051 receive the first downlink signal from the aggregation node 1 on the optical fiber, and then send it to the first optical transceiver module 06 for reception through the first optical switch 057. In addition, the first optical transceiver module 06 can also generate a first uplink signal based on the local oscillator light output by the first light source module 04, send the first uplink signal to the first splitting unit 052 through the first optical switch 057, and then send it to the optical fiber through the first combining unit 051, thereby communicating with the aggregation node 1. The first uplink signal sent to the optical fiber and the first downlink signal received from the optical fiber are also transmitted in the same optical fiber, and the transmission directions are opposite.

[0100] When the entire optical communication network link is fault-free, the first optical switch 057 can connect the optical path between the first optical transceiver module 06 and the first splitting unit 052, or it can connect the optical path between the first optical transceiver module 06 and the second splitting unit 054; this application does not limit this. It should be noted that the leaf node may also include a processing unit for controlling the first optical switch 057, which may be a digital signal processor (DSP), etc. When a link failure occurs between the first combining unit 051 and the aggregation node 1, the processing unit controls the first optical switch 057 to connect the optical path between the first optical transceiver module 06 and the second splitting unit 054. Conversely, when a link failure occurs between the second combining unit 053 and the aggregation node 2, the processing unit controls the first optical switch 057 to connect the optical path between the first optical transceiver module 06 and the first splitting unit 052.

[0101] Specifically, the second splitting unit 054 can divide the received second downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the first optical switch 057 and the first combining unit 051 respectively. It can also send the second uplink signal sent from the first optical switch 057 to the second combining unit 053, where M is an integer greater than 1. Similar to the first splitting unit 052, the second splitting unit 054 can also include a coupler and an uplink / downlink splitting module, with the same structure. Figure 11 As shown in the embodiment of this application, the coupler and uplink / downlink splitting module included in the second splitting unit 054 are referred to as the second coupler and the second uplink / downlink splitting module, respectively. A single port on one side of the second coupler is connected to the second combining unit 053, and there are at least two ports on the other side, which are connected to the first combining unit 051 and the second uplink / downlink splitting module, respectively. The second uplink / downlink splitting module can also be any one of a coupler, a circulator, or a multiplexer, used to transmit downlink signals from the second coupler and output uplink signals to the second coupler.

[0102] The leaf nodes provided in this embodiment can also be expanded. For example, the leaf nodes can include more light source modules, optical transceiver modules, and more optical switches, which can simultaneously realize the transmission and reception of multiple uplink and downlink signals. If the aggregation node can also support the transmission and reception of these signals, the system capacity can be expanded. Figure 16 The diagram shows a possible structure of an expanded leaf node, which also includes a second light source module 07 and a second optical transceiver module 08. The link splitting module 05 further includes a third splitting unit 055, a fourth splitting unit 056, and a second optical switch 058. The second optical switch 058 is used to switch the optical path between the second optical transceiver module 07 and the third splitting unit 055 and between the second optical transceiver module 07 and the fourth splitting unit 056. Similar to the first optical switch, when a link failure occurs between the first combining unit 051 and the aggregation node 1, the second optical transceiver module 07 connects to the fourth splitting unit 056 via the second optical switch 058. When a link failure occurs between the second combining unit 053 and the aggregation node 2, the second optical transceiver module 07 connects to the third splitting unit 055 via the second optical switch 058. Alternatively, an optical switch with a larger switching capacity can be used to implement the functions of the first optical switch 057 and the second optical switch 058. The functions of the second optical transceiver module and the second light source module are similar to those of the first optical transceiver module and the first light source module in the previous embodiment, and will not be described again in this embodiment.

[0103] At this time, the first combining unit 051 receives the third downlink signal from the optical fiber and sends it to the third splitting unit 055; the second combining unit 053 receives the fourth downlink signal from the optical fiber and sends it to the fourth splitting unit 056. The leaf node provided in this embodiment can receive any two downlink signals, and similarly, can send any two uplink signals, thus improving system capacity. Similarly, the first combining unit 051 and the second combining unit 053 can also branch out more paths and connect more splitting units, further expanding the system capacity.

[0104] In this embodiment, the use of optical switches reduces the number of optical transceiver modules and light source modules in the leaf nodes, lowering costs while retaining protection switching functionality. Furthermore, the link splitting module 05 provided in this embodiment includes different splitting units, allowing the first splitting unit 052 and the second splitting unit 054 to employ different splitting ratios to optimize the downlink power and pass-through power of the downlink signals from aggregation nodes 1 and 2.

[0105] Optionally, the optical switch can also be located between the light source module and the optical transceiver module, in which case the structure of the leaf node is as follows: Figure 17 As shown, it includes a first light source module 04, a link splitting module 05, a first optical transceiver module 06, a second optical transceiver module 07, and an optical switch 13. The link splitting module 05 receives a first downlink signal and a second downlink signal from the optical fiber, splits the first downlink signal into N first sub-downlink signals, and sends one first sub-downlink signal to the first optical transceiver module 06. It also splits the second downlink signal into M second sub-downlink signals and sends one second sub-downlink signal to the second optical transceiver module 07, where N and M are both positive integers greater than 1. The specific structure of the link splitting module 05 can be described as follows: Figure 13 As shown in the previous embodiments, this embodiment will not repeat the details.

[0106] Optical switch 13 is used to switch the optical path between the first light source module 04 and the first optical transceiver module 06, and between the first light source module 04 and the second optical transceiver module 07. Assuming that in the optical communication network, the leaf node provided in this embodiment receives a first downlink signal from the aggregation node 1 through the first optical transceiver module 06 and a second downlink signal from the aggregation node 2 through the second optical transceiver module 07, then when the link splitter module 05 cannot receive the first downlink signal, the optical path between the first light source module 04 and the second optical transceiver module 07 is connected through optical switch 13; when the link splitter module 05 cannot receive the second downlink signal, the optical path between the first light source module 04 and the first optical transceiver module 06 is connected through optical switch 13, realizing a protection switching function, ensuring communication is not interrupted in the event of a link failure. When the link is not faulty, optical switch 13 can be used to connect either the optical path between the first light source module 04 and the first optical transceiver module 06 or the optical path between the first light source module 04 and the second optical transceiver module 07 by default; this application does not impose any limitations.

[0107] When connected to the first optical transceiver module 06, the first light source module 04 provides the first local oscillator light and the first signal light to the first optical transceiver module 06. The first optical transceiver module 06 then uses the first local oscillator light to obtain a downlink signal with a wavelength matching that of the first local oscillator light from the received downlink signal. Furthermore, the first optical transceiver module 06 also generates a first uplink signal with a wavelength different from that of the first downlink signal based on the first signal light, and sends the generated first uplink signal to the link splitting module 05. The link splitting module 05 then transmits the first uplink signal to the optical fiber. The first uplink signal transmitted to the optical fiber and the first downlink signal received from the optical fiber are transmitted in the same optical fiber, but in opposite directions.

[0108] When the first light source module 04 is connected to the second optical transceiver module 07, it provides the second local oscillator light and the second signal light to the second optical transceiver module 07. The wavelength of the second signal light is different from that of the first signal light. The second optical transceiver module 07, based on the second local oscillator light, obtains a downlink signal with a wavelength matching that of the second local oscillator light from the received downlink signal. It also generates a second uplink signal with a wavelength different from that of the second downlink signal based on the second signal light. The link splitting module 05 sends the second uplink signal to the optical fiber. The second uplink signal sent to the optical fiber and the second downlink signal received from the optical fiber are transmitted in the same optical fiber and in opposite directions.

[0109] The leaf nodes provided in this embodiment can also be expanded. Similar to the expansion method in the previous embodiment, the first combining unit 051 and the second combining unit 053 in the link splitting module 05 can split more paths and connect more splitting units to achieve further expansion of the system. Moreover, by using optical switches, the number of light source modules in the leaf nodes is reduced while retaining the protection switching function, thus reducing costs.

[0110] In this application embodiment, the description is based on the existence of one fault location. When there are multiple fault locations, the solution of this application may only enable some leaf nodes to resume communication, but it can also solve the problem of some nodes being unable to communicate.

[0111] The leaf nodes and sink nodes described in this application embodiment can be arbitrarily combined to form an optical communication network without violating the processing logic.

[0112] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items with substantially the same function. It should be understood that there is no logical or temporal dependency between "first" and "second," nor does it limit the quantity or execution order. It should also be understood that although the following description uses the terms "first," "second," etc., to describe various elements, these elements should not be limited by the terms. These terms are merely used to distinguish one element from another. For example, without departing from the scope of various examples, a first optical transceiver module can be referred to as a second optical transceiver module, and similarly, a second optical transceiver module can be referred to as a first optical transceiver module. Both the first and second optical transceiver modules can be optical transceiver modules, and in some cases, they can be separate and different optical transceiver modules.

[0113] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication node, characterized in that, The communication node includes a first light source module, a link splitting module, and a first optical transceiver module; The first light source module is used to provide the first local oscillator light and the first signal light to the first optical transceiver module; The link splitting module is used to receive a first downlink signal from the optical fiber, divide the first downlink signal into N first sub-downlink signals, and send one first sub-downlink signal to the first optical transceiver module and the next node respectively, where N is a positive integer greater than 1; the first downlink signal is a multi-subcarrier signal; The first optical transceiver module is configured to acquire one or more subcarrier signals whose wavelengths match the wavelengths of the first local oscillator light from the received first sub-downlink signal based on the first local oscillator light; and is also configured to generate a first uplink signal with a wavelength different from the wavelength of the first downlink signal based on the first signal light, and send the first uplink signal to the link splitting module. The link splitting module is further configured to send the first uplink signal to the optical fiber, wherein the first uplink signal and the first downlink signal are transmitted in the same optical fiber and in opposite directions.

2. The communication node according to claim 1, characterized in that, The wavelengths of the first local oscillator light and the first signal light are different.

3. The communication node according to claim 1, characterized in that, The link splitting module includes a first combining unit, a first splitting unit, and a second combining unit; The first combining unit is used to receive the first downlink signal from the optical fiber and send the first downlink signal to the first splitting unit; The first splitting unit divides the first downlink signal into N first sub-downlink signals and sends one first sub-downlink signal to the first optical transceiver module and the second combining unit respectively; it is also used to receive the first uplink signal and send the first uplink signal to the first combining unit. The first combining unit is also used to send the first uplink signal to the optical fiber; The second combining unit is used to transmit one of the received first sub-downlink signals to the optical fiber.

4. The communication node according to claim 3, characterized in that, The link splitting module also includes an optical switch and a second splitting unit; The optical switch is used to switch the optical path between the first optical transceiver module and the first splitter unit and the optical path between the first optical transceiver module and the second splitter unit. The second combining unit is further configured to receive a second downlink signal from the optical fiber and send the received downlink signal to the second splitting unit; The second splitting unit is used to split the received downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the optical switch and the first combining unit respectively; and send the uplink signal sent by the optical switch to the second combining unit. The first combining unit is also used to transmit one received second sub-downlink signal to the optical fiber; The second combining unit is further configured to transmit the received uplink signal to the optical fiber, wherein the uplink signal transmitted by the second combining unit and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

5. The communication node according to claim 4, characterized in that, The optical switch is specifically used for: When a link failure occurs between the first combining unit and the aggregation node, the optical path between the first optical transceiver module and the second splitting unit is connected. When a link failure occurs between the second combining unit and the aggregation node, the optical path between the first optical transceiver module and the first splitting unit is connected.

6. The communication node according to claim 1, characterized in that, The communication node also includes a second light source module and a second optical transceiver module; The second light source module is used to provide the second local oscillator light and the second signal light to the second optical transceiver module; The link splitting module is further configured to receive a second downlink signal from the optical fiber, divide the second downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the second optical transceiver module and the next node respectively, wherein M is a positive integer greater than 1; The second optical transceiver module is configured to acquire a signal whose wavelength matches that of the second local oscillator light from the received second sub-downlink signal based on the second local oscillator light; and to generate a second uplink signal with a wavelength different from that of the second downlink signal based on the second signal light, and send the generated signal to the link splitting module. The link splitting module is further configured to send the second uplink signal to the optical fiber, wherein the second uplink signal and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

7. The communication node according to claim 1, characterized in that, The communication node also includes an optical switch and a second optical transceiver module; The optical switch is used to switch the optical path between the first light source module and the first optical transceiver module and between the first light source module and the second optical transceiver module. The first light source module is also used to provide the second local oscillator light and the second signal light to the second optical transceiver module; The link splitting module is further configured to receive a second downlink signal from the optical fiber, divide the second downlink signal into M second sub-downlink signals, and send one second sub-downlink signal to the second optical transceiver module and the next node respectively, wherein M is a positive integer greater than 1; The second optical transceiver module is configured to acquire a signal whose wavelength matches that of the second local oscillator light from the received second sub-downlink signal based on the second local oscillator light; and to generate a second uplink signal with a wavelength different from that of the second downlink signal based on the second signal light, and send the generated signal to the link splitting module. The link splitting module is further configured to send the second uplink signal to the optical fiber, wherein the second uplink signal and the second downlink signal are transmitted in the same optical fiber and in opposite directions.

8. The communication node according to claim 7, characterized in that, The optical switch is specifically used for: When the link splitter module fails to receive the first downlink signal, the optical path between the first light source module and the second optical transceiver module is connected. When the link splitter module is unable to receive the second downlink signal, the optical path between the first light source module and the first optical transceiver module is connected.

9. The communication node according to any one of claims 6-8, characterized in that, The link splitting module includes a first combining unit, a first splitting unit, a second splitting unit, and a second combining unit; The first combining unit is used to receive the first downlink signal from the optical fiber and send the first downlink signal to the first splitting unit; The first splitting unit divides the first downlink signal into N first sub-downlink signals and sends one first sub-downlink signal to the first optical transceiver module and the second combining unit respectively; it is also used to receive the first uplink signal and send the first uplink signal to the first combining unit. The second combining unit is used to receive the second downlink signal from the optical fiber and send the second downlink signal to the second splitting unit; The second splitting unit divides the second downlink signal into M second sub-downlink signals and sends one second sub-downlink signal to the second optical transceiver module and the first combining unit, respectively; it is also used to receive the second uplink signal and send the second uplink signal to the second combining unit. The first combining unit is used to transmit the first uplink signal and a received second sub-downlink signal to the optical fiber; The second combining unit is used to transmit the second uplink signal and a received first sub-downlink signal to the optical fiber.

10. The communication node according to any one of claims 4-8, characterized in that, The four signals output by the link splitting module to the optical fiber have different wavelengths.

11. The communication node according to any one of claims 4-5, characterized in that, The wavelength difference between the two signals output by the first combining unit is not greater than the gain spectral width of the amplifier; and / or, the wavelength difference between the two signals output by the second combining unit is not greater than the gain spectral width of the amplifier.

12. The communication node according to any one of claims 4-5, characterized in that, The first splitting unit includes a first coupler and a first uplink / downlink splitting module. A single port on one side of the first coupler is connected to the first combining unit, and two ports on the other side are respectively connected to the second combining unit and the first uplink / downlink splitting module. The first uplink / downlink splitting module is used to send downlink signals from the first coupler and output uplink signals to the first coupler. The second splitting unit includes a second coupler and a second uplink / downlink splitting module. A single port on one side of the second coupler is connected to the second combining unit, and two ports on the other side are respectively connected to the first combining unit and the second uplink / downlink splitting module. The second uplink / downlink splitting module is used to send downlink signals from the second coupler and output uplink signals to the second coupler.

13. The communication node according to claim 12, characterized in that, The first uplink / downlink splitter module and the second uplink / downlink splitter module are each of a coupler, a circulator, and a multiplexer.

14. The communication node according to any one of claims 3-5, characterized in that, The first combining unit and the second combining unit are either a multiplexer or a coupler.

15. A communication node, characterized in that, The communication node includes a splitter module, a light source module, and an optical transceiver module; The splitter module is used to receive uplink signals from optical fiber and send the uplink signals to the optical transceiver module; The light source module is used to provide local oscillator light and signal light to the optical transceiver module; The optical transceiver module is used to receive uplink signals sent by the splitter module based on the local oscillator light; it is also used to generate downlink signals based on the signal light and send the downlink signals to the splitter module, wherein the receiving bandwidth of the optical transceiver module covers the wavelength range of the uplink signal with the local oscillator light as the center. The splitter module is used to send downlink signals received from the optical transceiver module to the optical fiber, wherein the uplink signal and the downlink signal are transmitted in the same optical fiber and in opposite directions; the downlink signal is a multi-subcarrier signal.

16. The communication node according to claim 15, characterized in that, The splitter module can be any one of a coupler, a multiplexer, or a circulator.

17. An optical communication network, characterized in that, The optical communication network includes a first aggregation node, multiple leaf nodes, and a second aggregation node; The first aggregation node, the plurality of leaf nodes, and the second aggregation node are connected in series via optical fiber, with the first aggregation node and the second aggregation node being the start and end points of the series connection, respectively. The first aggregation node and the second aggregation node are respectively the communication nodes according to claim 15 or 16, and the leaf node is the communication node according to any one of claims 1 to 14.

18. The optical communication network according to claim 17, characterized in that, The uplink signal wavelengths output by the multiple leaf nodes to the first aggregation node are different, and the uplink signal wavelengths output by the multiple leaf nodes to the second aggregation node are also different.

19. The optical communication network according to claim 17 or 18, characterized in that, The optical communication network also includes a bidirectional amplification module located between any two nodes, used to bidirectionally amplify the signals transmitted in the optical fiber.

20. The optical communication network according to claim 19, characterized in that, The bidirectional amplification module includes a third combining unit, a first optical amplifier, a second optical amplifier, and a fourth combining unit; The first optical signal is sent to the first optical amplifier through the third combining unit. After being amplified by the first optical amplifier, the amplified signal is sent to the optical fiber through the fourth combining unit. The second optical signal is sent to the second optical amplifier through the fourth combining unit. After being amplified by the second optical amplifier, the amplified signal is sent to the optical fiber through the third combining unit. The first optical signal and the second optical signal are transmitted in opposite directions on the optical fiber.

21. The optical communication network according to claim 20, characterized in that, The third and fourth combining units are any one of a multiplexer, a coupler, or a circulator.

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