A method of optical fiber link fault detection, communication system and apparatus

Abstract

The application discloses a kind of optical fiber link fault detection method, communication system and device, it is related to optical communication technical field.In the method: first node includes the first identification sequence obtained by p order fractional fourier transform in the first service optical signal sent to second node.And, first node obtains fractional fourier transform spectrum by (1-p) order fractional fourier transform to received optical signal, the reflected optical signal of first service optical signal is included in the received optical signal, the peak of the fractional fourier transform spectrum indicates the energy of first identification sequence.Further, first node carries out peak detection to fractional fourier transform spectrum, obtains the signal intensity variation curve of first identification sequence, and the curve can be used to carry out fault detection to the optical fiber link between first node and second node.Based on this, first node can monitor the state of link in real time during service transmission, without additional optical time domain reflection detection device.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a method, communication system and device for detecting optical fiber link faults. Background Technology

[0002] Fiber optic link fault detection is crucial for the maintenance of optical communication systems. This includes detecting abnormal reflection points and increased loss within the link, and diagnosing the location of these anomalies. Typically, this is achieved by utilizing the principle that the intensity of the reflected light signal decreases with increasing transmission distance to determine the type and location of the fault—the working principle of an optical time domain reflectometer (OTDR). An OTDR system consists of two parts: a transmitting section that emits periodic light pulses into the optical link, and a receiving section that detects the intensity of the reflected light pulses. Averaging is then used to obtain the light pulse signal intensity that linearly decreases with increasing transmission distance. When the intensity becomes abnormal, such as a sudden increase or decrease, the corresponding location is the point of link failure. Because the transmission and detection methods of OTDR signals differ from those of normal communication signals, OTDR devices are usually independent of the communication transceiver. One form is a handheld OTDR instrument, which detects faults after a fiber optic link failure, such as a fiber break, lacking real-time capability. Another form is a standalone OTDR board or module, independent of the communication device, requiring additional cost. Especially in point-to-multipoint passive optical networks, coherent OTDR devices are typically used to detect reflected light signals under two-stage splitting ratios and large optical link insertion losses, which is extremely costly. Summary of the Invention

[0003] This application provides a fiber optic link fault detection method, communication system, and apparatus to solve the problems of high cost and untimely implementation of fiber optic link fault detection that require additional OTDR devices in the prior art.

[0004] To achieve the above objectives, this application adopts the following technical solution:

[0005] Firstly, this application provides a fiber optic link fault detection method. This method can be applied to a first node, or it can be applied to a module within the first node, such as a chip or chip system. The following description uses the first node as the executing entity. The fiber optic link fault detection method may include: the first node sending a first service optical signal to a second node, wherein the first service optical signal includes a first identifier sequence, which is obtained by performing a p-order fractional Fourier transform on a first constant sequence. The first node acquires a received optical signal, which may include the reflected optical signal generated by backscattering of the first service optical signal during fiber transmission. The first node performs a (1-p)-order fractional Fourier transform on the received optical signal to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal. The first node performs peak detection on the fractional Fourier transform spectrum to obtain a curve showing the signal strength of the first identifier sequence changing with transmission distance. This signal strength change curve can be used to detect faults in the fiber optic link between the first node and the second node.

[0006] Based on this scheme, the first node can detect link faults between itself and the second node during service transmission by using the reflected signal of the first service optical signal. This scheme can be continuously executed during service transmission, enabling real-time link fault monitoring, and it can share a single transceiver device with the service signal, eliminating the need for an additional OTDR device.

[0007] In one alternative implementation, the first constant sequence is transformed by a p-th order fractional Fourier transform to obtain the first identifier sequence, which can be achieved by the following formula: Where x(t) is the first constant sequence, X p (u) represents the first identifier sequence, and p represents the order of the fractional Fourier transform.

[0008] In one alternative implementation, the first identifier sequence may be generated by the first node performing a p-order fractional Fourier transform on the first constant sequence. Alternatively, the first identifier sequence may be pre-configured in the first node.

[0009] In one alternative implementation, during the transmission of the first service optical signal, the first node may insert a first identifier sequence into a specified position in the first service optical signal, which may be the head, tail, or other position of the first service optical signal.

[0010] In one alternative implementation, the first node performs a (1-p)-order fractional Fourier transform on the received optical signal, which can be achieved using the following formula:

[0011]

[0012] Where y(t) is the received optical signal, Y (1-p) (u) represents the fractional Fourier transform spectrum, and (1-p) represents the order of the fractional Fourier transform.

[0013] In one alternative implementation, the received optical signal acquired by the first node may also include a second service optical signal from the second node.

[0014] In one alternative implementation, the second service optical signal may include a second identifier sequence, which is obtained by performing a q-order fractional Fourier transform on a second constant sequence, where p is not equal to q. Based on this scheme, the second node can also perform actions similar to those on the first node to jointly achieve link fault detection.

[0015] In one alternative implementation, the first node is connected to multiple nodes via an optical splitter, and the aforementioned second node can be any one of the multiple nodes. These multiple nodes can transmit service optical signals to the first node in a time-division multiplexing manner via the optical splitter.

[0016] In one alternative implementation, if the first node is connected to multiple nodes via a splitter, including a third node, the received optical signal acquired by the first node may further include a third service optical signal from the third node. This third service optical signal includes a third identifier sequence, which can be obtained by performing an r-order fractional Fourier transform on a third constant sequence, where r is not equal to p and r is not equal to q.

[0017] In one optional implementation, the first node can be an optical line terminal (OLT), and the second and third nodes can be optical network units (ONUs). The optical link fault detection method provided in this embodiment may further include: the first node sending a first ONU management and control interface (OMCI) message or a first physical layer operations, administration and maintenance (PLOAM) message to the second node, wherein the first OMCI message or the first PLOAM message is used to indicate the order q; and the first node sending a second OMCI message or a second PLOAM message to the third node, wherein the second OMCI message or the second PLOAM message is used to indicate the order r.

[0018] In a second aspect, a communication system is provided, which may include the first node and the second node mentioned in the first aspect above.

[0019] The first node can transmit a first service optical signal to the second node. This first service optical signal may include a first identifier sequence, which is obtained by performing a p-order fractional Fourier transform on a first constant sequence. The first node can also acquire a received optical signal, which includes the reflected light signal generated by backscattering of the first service optical signal during fiber transmission. The first node can further perform a (1-p)-order fractional Fourier transform on the acquired received optical signal to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected light signal of the first service optical signal. The first node can also perform peak detection on the fractional Fourier transform spectrum to obtain a signal intensity variation curve of the first identifier sequence. This signal intensity variation curve can be used for fault detection in the fiber optic link between the first and second nodes.

[0020] In one alternative implementation, the second node can also be used to send a second service optical signal to the first node, and the received optical signal obtained by the first node also includes the second service optical signal from the second node.

[0021] In one alternative implementation, the second service optical signal includes a second identifier sequence, which is obtained by performing a q-order fractional Fourier transform on a second constant sequence, where q is not equal to p.

[0022] In one optional implementation, the second node can also be used to acquire the received optical signal, which includes the reflected optical signal generated by backscattering of the second service optical signal during optical fiber transmission. The second node can also perform a (1-q)-order fractional Fourier transform on the acquired optical signal to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the second identifier sequence in the reflected optical signal of the second service optical signal. The second node can also perform peak detection on the fractional Fourier transform spectrum to obtain a signal intensity variation curve of the second identifier sequence; this signal intensity variation curve is used for fault detection in the optical fiber link between the second node and the first node.

[0023] Based on the above implementation method, the second node can also perform similar actions as the first node to jointly achieve link fault detection.

[0024] In one alternative implementation, the first node is connected to multiple nodes via an optical splitter, and these multiple nodes may include a second node. The service optical signals sent by these multiple nodes are transmitted to the first node in a time-division multiplexed manner.

[0025] Optionally, the system may further include a third node. This third node is any one of multiple nodes connected to the first node via an optical splitter. The third node can be used to send a third service optical signal to the first node, the third service optical signal including a third identifier sequence. The third identifier sequence is obtained by performing an r-order fractional Fourier transform on a third constant sequence, where r is not equal to p and r is not equal to q.

[0026] In one optional implementation, the third node can also be used to acquire the received optical signal, which includes the first service optical signal and the reflected optical signal generated by backscattering of the third service optical signal during optical fiber transmission. The third node can also perform a (1-r)-order fractional Fourier transform on the acquired optical signal to obtain the fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the third identifier sequence in the reflected optical signal of the third service optical signal. The third node can also perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity variation curve of the third identifier sequence. The signal intensity variation curve is used for fault detection of the optical fiber link between the third node and the splitter or the first node.

[0027] Based on the above implementation, in point-to-multipoint optical communication systems, the third node can also perform similar actions to the first node to jointly achieve link fault detection. Furthermore, different nodes use different orders of fractional Fourier transforms.

[0028] Thirdly, this application provides a communication device, which can be a first node, a chip or chip system within the first node, or a functional module within the first node for implementing the method described in any possible design of the first aspect. This communication device can implement the functions performed by the first node in the above aspects or possible designs, and these functions can be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the above functions. For example, the communication device includes a transmitting unit, a receiving unit, and a processing unit. The transmitting unit is used to transmit a first service optical signal to a second node, wherein the first service optical signal includes a first identifier sequence, which is obtained by performing a p-order fractional Fourier transform on a first constant sequence. The receiving unit is used to acquire a received optical signal, which includes the reflected optical signal generated by backscattering of the first service optical signal during optical fiber transmission. The processing unit is used to perform a (1-p)-order fractional Fourier transform on the received optical signal to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal. The processing unit is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity variation curve of the first identifier sequence. This signal intensity variation curve can be used for fault detection in the optical fiber link between the first node and the second node.

[0029] In one alternative implementation, the first constant sequence is transformed by a p-th order fractional Fourier transform to obtain the first identifier sequence, which can be achieved by the following formula: Where x(t) is the first constant sequence, X p (u) represents the first identifier sequence, and p represents the order of the fractional Fourier transform.

[0030] In one alternative implementation, the first identifier sequence may be generated by the first node performing a p-order fractional Fourier transform on the first constant sequence. Alternatively, the first identifier sequence may be pre-configured in the first node.

[0031] In one alternative implementation, during the transmission of the first service optical signal, the first node may insert a first identifier sequence into a specified position in the first service optical signal, which may be the head, tail, or other position of the first service optical signal.

[0032] In one alternative implementation, the first node performs a (1-p)-order fractional Fourier transform on the received optical signal, which can be achieved using the following formula: Where y(t) is the received optical signal, Y (1-p0 (u) represents the fractional Fourier transform spectrum, and (1-p) represents the order of the fractional Fourier transform.

[0033] In one alternative implementation, the received optical signal acquired by the first node may also include a second service optical signal from the second node.

[0034] In one alternative implementation, the second service optical signal may include a second identifier sequence, which is obtained by performing a q-order fractional Fourier transform on a second constant sequence, where p is not equal to q.

[0035] In one alternative implementation, the first node is connected to multiple nodes via an optical splitter, and the aforementioned second node can be any one of these multiple nodes. These multiple nodes can transmit service optical signals to the first node in a time-division multiplexing manner via the optical splitter.

[0036] In one alternative implementation, if the first node is connected to multiple nodes via a splitter, including a third node, the received optical signal acquired by the first node may further include a third service optical signal from the third node. This third service optical signal may include a third identifier sequence, which can be obtained by performing an r-order fractional Fourier transform on a third constant sequence, where r is not equal to p and r is not equal to q.

[0037] In one alternative implementation, the first node can be an Optical Line Terminal (OLT), and the second and third nodes can be Optical Network Units (ONUs). In this case, the transmitting unit can also be used to send a first OMCI message or a first PLOAM message to the second node, the first OMCI message or the first PLOAM message indicating the order q. Furthermore, the transmitting unit can also be used to send a second OMCI message or a second PLOAM message to the third node, the second OMCI message or the second PLOAM message indicating the order r.

[0038] The technical effects of the various implementation methods in the third aspect can be referred to the description in the first aspect.

[0039] Fourthly, a communication device is provided, comprising: a communication interface and a processor; wherein the communication interface can be used to perform the sending and receiving actions in the optical fiber link fault detection method described in any one of the first aspects, and the processor is used to perform the processing actions in the optical fiber link fault detection method described in any one of the first aspects.

[0040] Fifthly, a communication device is provided, comprising: a processor; the processor being coupled to a memory, and after reading instructions from the memory, executing, according to the instructions, the fiber optic link fault detection method as described in any one of the first aspects above.

[0041] In one possible implementation, the communication device further includes a memory for storing computer instructions.

[0042] In one possible implementation, the communication device further includes a communication interface for communicating with other devices. For example, the communication interface may be a transceiver, an input / output interface, an interface circuit, an output circuit, an input circuit, pins, or related circuitry.

[0043] In one possible implementation, the communication device can be a chip or a chip system. When the communication device is a chip system, it can be composed of chips or may include chips and other discrete components.

[0044] In one possible implementation, when the communication device is a chip or chip system, the aforementioned communication interface can be an input / output interface, interface circuit, output circuit, input circuit, pin, or related circuit on the chip or chip system. The aforementioned processor can also be embodied as a processing circuit or logic circuit.

[0045] In a sixth aspect, a computer-readable storage medium is provided, which stores instructions that, when executed on a computer, cause the computer to perform the fiber optic link fault detection method described in any one of the first aspects.

[0046] The technical effects of any of the design methods in aspects four through six can be found in the technical effects of different design methods in aspect one, and will not be repeated here. Attached Figure Description

[0047] Figure 1 A schematic diagram of a point-to-point optical communication system provided in an embodiment of this application;

[0048] Figure 2 A schematic diagram of a point-to-multipoint optical communication system provided in an embodiment of this application;

[0049] Figure 3 This is a schematic diagram of the structure of a communication device provided in an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of another communication device provided in an embodiment of this application;

[0051] Figure 5 A flowchart of a fiber optic link fault detection method provided in an embodiment of this application;

[0052] Figure 6 This is a schematic diagram of the structure of another communication device provided in an embodiment of this application;

[0053] Figure 7 This is a schematic diagram of another communication device provided in an embodiment of this application. Detailed Implementation

[0054] Before introducing the embodiments of this application, the technical terms and related technologies involved in this application will be explained. It should be noted that the following explanations are for the purpose of making the embodiments of this application easier to understand, and should not be regarded as a limitation on the scope of protection claimed by the embodiments of this application.

[0055] Rayleigh scattering: Scattering is the phenomenon where light rays propagate in all directions when passing through a medium with non-uniform optical properties. Scattering can include many types, including Rayleigh scattering. In Rayleigh scattering, the scattering wavelength is the same as the incident wavelength, the intensity of the scattered light is inversely proportional to the fourth power of the wavelength, and the intensity of the scattered light is distributed in a dumbbell-shaped angular pattern in space.

[0056] Rayleigh scattering also occurs when signal light propagates in optical fibers. Scattering happens in all directions in space, including forward and backward scattering along the fiber axis. Rayleigh backscattering along the fiber axis is commonly referred to as Rayleigh backscattering. Backscattered light returns to the light source along the fiber, and thus, backscattered light can also be called reflected light.

[0057] OTDR utilizes the Rayleigh scattering effect. The light pulses emitted by the OTDR's transmitting section undergo Rayleigh scattering in the optical link. The backscattered light pulses (also called reflected light pulses) return along the optical fiber to the OTDR and are received by its receiving section. The OTDR's receiving section can detect the intensity of the reflected light pulses and, using the principle that the optical signal decreases with increasing transmission distance, determine the type and location of fiber optic faults.

[0058] It's important to note that optical signal transmission typically uses continuous light, while OTDRs emit optical pulses. Continuous light has a low signal strength, resulting in reflected light with a similarly low signal strength, making it unsuitable for diagnosing fiber optic link faults. In contrast, optical pulses have a high signal strength, and the reflected light within the fiber also exhibits a high signal strength. The signal strength of an optical pulse decreases with increasing transmission distance, a phenomenon that can be perceived and thus used to detect fiber optic link faults. Therefore, OTDRs utilize optical pulses.

[0059] As described in the background section, existing technologies using OTDRs for link detection lack real-time performance and are costly. Therefore, the following technical solutions based on embodiments of this application are provided.

[0060] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. In the description of this application, unless otherwise stated, " / " indicates that the objects before and after are in an "or" relationship. For example, A / B can represent A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone, where A and B can be singular or plural. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple. Furthermore, to facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that "first" and "second" are not necessarily different. Meanwhile, in the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is being used as an example, illustration, or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of terms such as "exemplary" or "for example" is intended to present related concepts in a concrete manner for ease of understanding. In the embodiments of this application, "system" and "network" can express the same meaning and are interchangeable; for example, "communication system" can also be called "communication network".

[0061] The fiber optic link fault detection method provided in this application can be applied to optical communication systems (also known as optical communication networks). These systems can be single-node-to-single-node communication, such as coherent optical communication systems in backbone networks, or single-node-to-multi-node communication, such as passive optical network (PON) systems and passive optical LAN (POL) systems in access networks. When the point-to-multipoint optical communication system is a PON, the PON can be an asynchronous transfer mode (ATM) based PON (ATM-PON, APON), a broadband passive optical network (BPON), an Ethernet PON (EPON), or a gigabit-capable PON (GPON), etc. This application does not limit the type of PON.

[0062] Figure 1 The diagram shows a point-to-point optical communication system according to an embodiment of this application. The optical communication system may include node 1 and node 2, which can be directly connected by optical fiber to realize optical communication.

[0063] Figure 2 This illustration shows a schematic diagram of a point-to-multipoint optical communication system according to an embodiment of this application. The optical communication system may include node A and nodes B1 to Bn. Node A can be connected to nodes B1 to Bn via a splitter, and node A can perform optical communication with any one of nodes B1 to Bn. Optionally, Figure 2 The optical communication system shown can be PON. In this case, node A can be an OLT, and nodes B1 to Bn can be ONUs.

[0064] Alternatively, optical communication between nodes in an optical communication system can be achieved based on intensity modulation direct detection or based on coherent detection.

[0065] As one possible implementation, in the case of optical communication between nodes based on intensity modulation direct detection, Figure 1 or Figure 2 The hardware implementation of the middle node can be adopted Figure 3 The provided implementation method. Figure 3This application provides a schematic diagram of a communication device, which may include a media access control (MAC) module 311, a signal processing module 312, a driver 313, a photodetector 314, a laser 315, and a connection unit 316. The connection unit 316 may be a coupler, a circulator, a filter, or a wavelength division multiplexer, etc.

[0066] In the transmission direction, MAC module 311 can be used to generate service data, signal processing module 312 can be used to process the service data, and laser 315, under the control of driver 313, modulates the service data processed by 312 into an optical signal. Laser 315 can then transmit the optical signal carrying the service data through connection unit 316 into an optical fiber, and subsequently through the optical fiber to other nodes. For example, consider a first node including... Figure 3 Taking the communication device shown as an example, the MAC module 311 can be used to generate a service message to be sent, the signal processing module 312 can be used to insert a first identifier sequence into the service message to be sent, and the laser 315, under the control of the driver 313, modulates the service message including the first identifier sequence into a first service optical signal. Detailed implementation methods can be found below. Figure 5 The corresponding method embodiments are described.

[0067] In the receiving direction, photodetector 314 receives an optical signal from connection unit 316, and photodetector 314 can convert the received optical signal into an electrical signal. Signal processing module 312 can process the electrical signal. MAC module 311 can parse the electrical signal processed by signal processing module 312 to obtain service data. For example, taking the first node as an example... Figure 3 Taking the communication device shown as an example, the photodetector 314 can convert the acquired received optical signal into an electrical signal, the signal processing module 312 can perform a (1-p)-order fractional Fourier transform on the converted electrical signal, and the MAC module 311 can parse the obtained fractional Fourier transform sequence. Detailed implementation methods can be found below. Figure 5 The corresponding method embodiments are described.

[0068] As another possible implementation, in the case of communication between nodes based on coherent probing... Figure 1 or Figure 2 The hardware implementation of the node shown can be adopted Figure 4 The provided implementation method. Figure 4This is a schematic diagram of a communication device provided in an embodiment of this application. The communication device may include: a laser 411a, a laser 411b, a beam splitter 412a, a coupler 412b, a coherent transmitter 413, a coherent receiver 414, a MAC module 415, and a connection unit 416. The connection unit 416 may be a coupler, a circulator, or a filter, etc.

[0069] In the transmission direction, the laser emitted by laser 411a is input to coherent transmitter 413 via beam splitter 412a. MAC module 415 can be used to generate service signals, and coherent transmitter 413 can be used to modulate the service signals into the laser, thereby outputting an optical signal. The transmitted optical signal enters the optical fiber through connection unit 416, and is then sent to other nodes.

[0070] In the receiving direction, the coherent receiver 414 receives optical signals via the connection unit 416. The received optical signals may include optical signals transmitted by other nodes and reflected signals of signals transmitted by this node. The laser emitted by laser 411a can be input to the coherent receiver 414 via coupler 412b, and can be used to beat the reflected signals of the optical signals transmitted by this node. The laser emitted by laser 411b serves as the local oscillator laser for beating the optical signals transmitted by other nodes, and performs coherent reception processing on the optical signals transmitted by other nodes. The coherent receiver 414 receives and processes the optical signals, and the processed electrical signals are input to the MAC module 415. The MAC module 415 can parse the coherently received signals to obtain service data.

[0071] Understandable, Figure 1 and Figure 2 These are merely possible implementations of the optical communication network provided in this application. Figure 3 and Figure 4 The possible implementations of the communication device provided in this application should not be construed as limiting this application. For example, an optical communication network may include more or fewer nodes, and there may be other connections between the nodes; also, the hardware structure of the communication device may be added to, removed from, or replaced with other hardware components.

[0072] The fiber optic link fault detection method based on reflected light from service optical signals provided in this application embodiment can be applied to point-to-point optical communication scenarios (e.g., Figure 1 The optical communication system shown can also be applied to point-to-multipoint optical communication scenarios (e.g., Figure 2 (The optical communication system shown).

[0073] Below Figure 1 or Figure 2 Based on the optical communication system shown, this embodiment provides a possible implementation method for achieving fault detection of the optical fiber link, such as... Figure 5 As shown, Figure 5 A flowchart of a fiber optic link fault detection method is shown, which may include steps 501 to 504.

[0074] Step 501: The first node sends a first service optical signal to the second node. The first service optical signal includes a first identifier sequence, which is obtained by p-order fractional Fourier transform of a first constant sequence.

[0075] In this application embodiment, the service optical signal is an optical signal modulated according to the service message / data (electrical signal), which is uniformly described in this application.

[0076] Optionally, the complete electrical signal corresponding to the first service optical signal may include a first electrical signal corresponding to the first service message and a second electrical signal corresponding to the first identifier sequence. The first node modulates the complete electrical signal including the first and second electrical signals to obtain the first service optical signal.

[0077] Optionally, during the process of generating the complete electrical signal corresponding to the first service optical signal, the first node may insert the first identification sequence (electrical signal) into a specified position in the first service message (electrical signal), which may be the header, tail, or other position of the first service message.

[0078] Optionally, the first identifier sequence may be pre-configured in the first node, or it may be obtained by performing a p-order fractional Fourier transform on the first constant sequence by the first node. This application does not limit this.

[0079] The first constant sequence is transformed by a p-order fractional Fourier transform to obtain the first identifier sequence, which can be achieved by the following formula (1).

[0080]

[0081] Where x(t) is the first constant sequence, X p (u) represents the first identifier sequence, p represents the order of the fractional Fourier transform (also known as the order), t represents time, u represents the variables in the transform domain after the fractional Fourier transform, j represents the imaginary number in complex number operations, e represents a natural number, and α represents the angle of the fractional Fourier transform (FrFT) sequence (i.e., the first identifier sequence) in the Wigner domain. p is any value between -1 and 1.

[0082] For example, the first constant sequence can be a DC component, such as [111……111].

[0083] Step 502: The first node acquires the received optical signal, which includes the reflected optical signal generated by back Rayleigh scattering during the transmission of the first service optical signal in the optical fiber.

[0084] When the first service optical signal transmitted by the first node is transmitted in the optical fiber, Rayleigh scattering occurs. The scattered light includes backscattered light that returns to the first node along the optical fiber. This backscattered light can be considered as the reflected light signal of the first service optical signal. Therefore, the received optical signal acquired by the first node includes the reflected light signal of the first service optical signal.

[0085] Optionally, this fiber optic link fault detection method can be applied during service transmission between the first node and the second node. Therefore, the received optical signal acquired by the first node may also include a second service optical signal from the second node.

[0086] Step 503: The first node performs a (1-p)-order fractional Fourier transform on the received optical signal to obtain the fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal.

[0087] As shown in step 502, the received optical signal acquired by the first node includes the reflected signal of the first service optical signal. When the first node performs a (1-p)-order fractional Fourier transform on the received optical signal, it also performs a (1-p)-order fractional Fourier transform on the reflected optical signal of the first service optical signal. Since the reflected optical signal of the first service optical signal includes the first identifier sequence, the first node also performs a (1-p)-order fractional Fourier transform on the first identifier sequence.

[0088] It should be noted that FrFT sequences of different orders will form rotations at different angles in the Wigner domain, exhibiting energy concentration at their respective angles. This process is beneficial for extracting energy features from weak signals, which can be reflected in the signal processing of optical signal receiving devices. For example, an optical receiving device (such as the first node mentioned above) can perform a (1-p)-order FrFT transform on a received optical signal including a p-order FrFT sequence. The resulting FrFT sequence will contain maxima, which indicate the energy concentration phenomenon exhibited by the p-order FrFT sequence.

[0089] Based on the above principle, after performing a (1-p)-order fractional Fourier transform on the received optical signal, the first node can obtain the energy of the first identifier sequence in the received optical signal. In other words, the first node can determine the energy of the optical signal reflected by the first identifier sequence during the transmission of the first service message through the (1-p)-order fractional Fourier transform process.

[0090] Optionally, the first node performs a (1-p)-order fractional Fourier transform on the received optical signal, which is achieved by the following formula (2):

[0091]

[0092] Where y(t) is the received optical signal, Y (1-p) (u) represents the fractional Fourier transform spectrum, (1-p) represents the order of the fractional Fourier transform, t represents time, u represents the variables in the transform domain after the fractional Fourier transform, j represents the imaginary number in complex number operations, e represents a natural number, and β represents the angle of the fractional Fourier transform sequence (i.e., the first identifier sequence) in the Wigner domain.

[0093] Step 504: The first node performs peak detection on the obtained fractional Fourier transform spectrum to obtain the signal intensity variation curve of the first identifier sequence. The signal intensity variation curve is used for fault detection in the optical fiber link between the first node and the second node.

[0094] Since the peak value of the fractional Fourier transform spectrum indicates the energy of the first identifier sequence, the first node can determine the energy of the first identifier sequence by performing peak detection on the fractional Fourier transform spectrum. Thus, the first node can detect faults in the optical fiber link by detecting changes in the energy of the first identifier sequence.

[0095] Based on the aforementioned principle of OTDR using reflected signals to detect fiber optic link faults, possible examples of fault detection provided in this embodiment will be described. For example, if the signal strength change curve of the first identifier sequence decreases linearly and smoothly, the first node can determine that the fiber optic link is in a normal state. Conversely, if the signal strength change curve of the first identifier sequence shows abnormal fluctuations (such as a sudden drop in the curve), the first node can determine that the fiber optic link has failed.

[0096] During continuous transmission of optical signals, the energy change curve (such as the signal strength change curve in step 504) determined by the first node through continuous processing of the received optical signal reflects the real-time trend of energy change. Analysis of this signal strength change curve by the first node enables real-time fault detection of the optical fiber link, improving the timeliness of fault detection. In summary, the first node can carry a first identifier sequence obtained by a p-order fractional Fourier transform in the transmitted first service optical signal. Furthermore, the first node can also perform a (1-p)-order fractional Fourier transform on the received optical signal to obtain the fractional Fourier transform spectrum, which includes the reflected optical signal of the first service optical signal. The peak value of this fractional Fourier transform spectrum indicates the energy of the first identifier sequence. Therefore, the first node can detect the energy of the first identifier sequence based on the fractional Fourier transform spectrum, and the energy change of the first identifier sequence can be used to achieve fault detection of the optical fiber link.

[0097] The first node can continuously receive and process the received optical signal, thereby obtaining a continuous signal strength variation curve of the first identifier sequence. This signal strength variation curve reflects the change in the energy value of the optical signal reflected by the first identifier sequence during the transmission of the first service optical signal through the optical fiber. This signal strength variation curve can reflect the real-time transmission status of the signal, and therefore can be used to detect the status of the optical fiber link between the first node and the second node in real time, improving the timeliness of fault detection.

[0098] Furthermore, the fiber optic link fault detection method provided in this application can be implemented based on the usual service transmission process, is compatible with existing optical communication systems, requires no modification to the structure of the optical communication system, is easy to deploy and implement, and has low cost. Nodes implementing this link detection function can share a single transceiver device with the transmission of service signals, eliminating the need for additional OTDR devices and reducing the hardware cost required for fault detection of fiber optic links between nodes.

[0099] Optionally, in the above embodiments, the second node may also send a second service optical signal to the first node. The second service optical signal may include a second identifier sequence. The second identifier sequence may be obtained by performing a q-order fractional Fourier transform on a second constant sequence, where q is not equal to p. It should be understood that the second identifier sequence can refer to the relevant description of the first identifier sequence in step 501 above, and the formula for generating the second identifier sequence can refer to formula (1). Only the fractional Fourier transform order in formula (1) needs to be replaced with q.

[0100] It should be understood that FrFT sequences of different orders are orthogonal to each other in the fractional domain. The first node performs a (1-p) order fractional Fourier transform on the received optical signal. Therefore, the second identifier sequence of order q will not interfere with the first node's acquisition of the energy of the first identifier sequence of order p.

[0101] If the second service message includes a second identifier sequence, the method of this application may further include the following steps A(1) to A(3):

[0102] Step A (1) The second node acquires the received optical signal. The received optical signal acquired by the second node may include the reflected optical signal generated by the back Rayleigh scattering of the second service optical signal during optical fiber transmission.

[0103] Optionally, the received optical signal acquired by the second node may also include the first service optical signal.

[0104] Step A(1) can be referred to the relevant description of step 502 above.

[0105] Step A(2): The second node performs a (1-q)-order fractional Fourier transform on the received optical signal to obtain the fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the second identifier sequence in the reflected optical signal of the second service optical signal.

[0106] Step A(2) can be referred to the relevant description of step 503 above. The formula for the second node to perform a (1-q) order fractional Fourier transform on the received optical signal can be referred to formula (2) above. It is only necessary to replace the order of the fractional Fourier transform in formula (2) with 1-q.

[0107] Step A(3) The second node is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the second identifier sequence; wherein, the signal intensity change curve is used to perform fault detection on the optical fiber link between the second node and the first node.

[0108] Step A(3) can be referred to the relevant description of step 504 above.

[0109] As can be seen from the above steps, when the second service message includes the second identifier sequence, the second node can also detect fiber optic link faults by processing the received optical signal. In other words, both the first and second nodes are detecting the link status between them during service signal transmission.

[0110] Optionally, the fiber optic link fault detection method of this application can be applied to a point-to-point optical communication system, where the first node and the second node can be directly connected via optical fiber. For example, using... Figure 1Taking the point-to-point communication system shown as an example, the first node can be node 1, and the second node can be node 2. Alternatively, the first node can be node 2, and the second node can be node 1.

[0111] Optionally, the fiber optic link fault detection method for reflected service signal light of this application can be applied to point-to-multipoint optical communication systems. As one possible implementation, the first node can be connected to multiple nodes via a splitter, and the second node is one of those nodes. Figure 2 Taking the point-to-multipoint communication system shown as an example, the first node can be node A, and the second node can be any one of node B1 to node Bn.

[0112] Optionally, if the first node connects to multiple nodes via an optical splitter, the service optical signals sent by the multiple nodes can be transmitted to the first node in a time-division multiplexing manner.

[0113] Optionally, the first node may further include a third node among the multiple nodes connected to it via the optical splitter. Figure 2 Taking the point-to-multipoint communication system shown as an example, the third node can be any one of node B1 to node Bn, as long as the third node is different from the second node.

[0114] Optionally, the third service optical signal sent by the third node to the first node may include a third identifier sequence. The third identifier sequence is obtained by performing an r-order fractional Fourier transform on a third constant sequence, where r is not equal to p and r is not equal to q. It should be understood that the third identifier sequence can be referenced to the relevant description of the first identifier sequence in step 501 above, and the formula for generating the third identifier sequence can be referenced to formula (1), only requiring the fractional Fourier transform order in formula (1) to be replaced with r.

[0115] When the third service message includes a third identifier sequence, the method of this application may further include the following steps B(1) to B(3):

[0116] Step B(1) The third node acquires the received optical signal. The received optical signal acquired by the third node may include the reflected optical signal generated by the third service optical signal due to back Rayleigh scattering during optical fiber transmission.

[0117] Optionally, the received optical signal acquired by the third node may also include the first service optical signal.

[0118] Step B(1) can be referred to the relevant description of step 502 above.

[0119] Step B(2) The third node performs a (1-q)-order fractional Fourier transform on the received optical signal to obtain the fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the third identifier sequence in the reflected optical signal of the third service optical signal.

[0120] Step B(2) can refer to the relevant description of step 503 above. The formula for the third node to perform a (1-q) order fractional Fourier transform on the received optical signal can refer to formula (2) above. Just replace the order of the fractional Fourier transform in formula (2) with 1-q.

[0121] Step B(3) The third node is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the third identifier sequence; wherein, the signal intensity change curve is used to perform fault detection on the optical fiber link between the third node and the first node.

[0122] Step B(3) can be referred to the relevant description of step 504 above.

[0123] Based on the above description, when the method of this application is applied to a point-to-multipoint optical communication system, the service optical signals sent by the first node, the second node, and the third node can all carry an identification sequence. The difference is that the fractional Fourier transform order used for the identification sequences carried by different nodes is different.

[0124] As one possible implementation, when the first node is connected to the second and third nodes via the optical splitter, the first node can monitor the link status between the first node and the optical splitter based on the signal strength change curve of the first identifier sequence, the second node can monitor the link status between the second node and the optical splitter based on the signal strength change curve of the second identifier sequence, and the third node can monitor the link status between the third node and the optical splitter based on the signal strength change curve of the third identifier sequence.

[0125] In other words, when the method of this application is applied to a point-to-multipoint optical communication system, each node can monitor the link status between itself and the optical splitter based on the method provided in this application. Thus, link monitoring of the entire network is jointly completed by all nodes in the network. Therefore, this scheme can solve the problem that due to the influence of the optical splitter, reflected signals are difficult to distinguish between different splitting branches, making accurate link detection impossible. Furthermore, this scheme distributes the monitoring task to each node, reducing the workload of a single node, and the distributed deployment makes it easy to identify the link where the fault occurs.

[0126] Optionally, when the method of this application is applied to a point-to-multipoint optical communication system, the fractional Fourier transform orders used by multiple nodes at the user end can be issued by the central node at the exchange. For example, if the first node is connected to the second and third nodes via a splitter, the fractional Fourier transform orders of the second and third nodes can be indicated by the first node.

[0127] Optionally, when the method of this application is applied to a point-to-multipoint optical communication system, the first node can be an OLT, and the second and third nodes can be ONUs. In this case, the first node can send a first OMCI message or a first PLOAM message to the second node, which indicates the order q. Furthermore, the first node can also send a second OMCI message or a second PLOAM message to the third node, which indicates the order r.

[0128] It is understood that in the above embodiments, the methods and / or steps implemented by the first node can also be implemented by components (e.g., chips or circuits) that can be used in the first node, the methods and / or steps implemented by the second node can also be implemented by components (e.g., chips or circuits) that can be used in the second node, and the methods and / or steps implemented by the third node can also be implemented by components (e.g., chips or circuits) that can be used in the third node.

[0129] Optionally, embodiments of this application also provide a communication device for implementing the various methods described above. This communication device may also be a first node in the above method embodiments, or a device including the first node, or a component usable in the first node. Similarly, this communication device may be a second node in the above method embodiments, or a device including the second node, or a component usable in the second node. Furthermore, this communication device may be a third node in the above method embodiments, or a device including the third node, or a component usable in the third node. It is understood that, in order to implement the above functions, this communication device includes hardware structures and / or software modules corresponding to the execution of each function. Those skilled in the art should readily recognize that, based on the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0130] This application embodiment can divide the communication device into functional modules according to the above method embodiment. For example, each function can be divided into its own functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware or as a software functional module. It should be noted that the module division in this application embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0131] Figure 6 A schematic diagram of the structure of a communication device provided in this application is shown, with reference to... Figure 6 The communication device 60 may include a transmitting unit 601, a receiving unit 602, and a processing unit 603.

[0132] In this embodiment of the method, the communication device 60 is taken as the first node:

[0133] The transmitting unit 601 can be used to transmit a first service optical signal to the second node, wherein the first service optical signal includes a first identifier sequence, which is obtained by performing a p-order fractional Fourier transform on a first constant sequence. The receiving unit 602 can be used to acquire a received optical signal, which includes the reflected optical signal generated by backscattering of the first service optical signal during optical fiber transmission. The processing unit 603 can be used to perform a (1-p)-order fractional Fourier transform on the received optical signal to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal. The processing unit 603 can also be used to perform peak detection on the fractional Fourier transform spectrum to obtain a signal intensity variation curve of the first identifier sequence. The signal intensity variation curve can be used for fault detection in the optical fiber link between the first node and the second node.

[0134] Optionally, the first node can be connected to multiple nodes via an optical splitter, including a second node and a third node. The first node can be an Optical Line Terminal (OLT), and the second and third nodes can be Optical Network Units (ONUs). In this case, the transmitting unit 601 can also be used to send a first OMCI message or a first PLOAM message to the second node, the first OMCI message or the first PLOAM message indicating the order q. The transmitting unit 601 can also be used to send a second OMCI message or a second PLOAM message to the third node, the second OMCI message or the second PLOAM message indicating the order r.

[0135] Taking the communication device 60 as the second node in the above method embodiment as an example:

[0136] The transmitting unit 601 can be used to transmit a second service optical signal to the first node.

[0137] Optionally, the receiving unit 602 can be used to acquire a received optical signal, which may include the reflected optical signal generated by backscattering of the second service optical signal during optical fiber transmission. The processing unit 603 can be used to perform a (1-q)-order fractional Fourier transform on the received optical signal acquired by the second node to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the second identifier sequence in the reflected optical signal of the second service optical signal. The processing unit 603 can also be used to perform peak detection on the fractional Fourier transform spectrum to obtain a signal intensity variation curve of the second identifier sequence. The signal intensity variation curve can be used for fault detection in the optical fiber link between the second node and the first node.

[0138] Taking the communication device 60 as the third node in the above method embodiment as an example:

[0139] The transmitting unit 601 can be used to transmit the third service optical signal to the first node.

[0140] Optionally, the receiving unit 602 can be used to acquire a received optical signal, which may include the reflected optical signal generated by backscattering of the third service optical signal during optical fiber transmission. The processing unit 603 can be used to perform a (1-q)-order fractional Fourier transform on the received optical signal acquired by the third node to obtain a fractional Fourier transform spectrum. The peak value of the fractional Fourier transform spectrum corresponds to the energy of the third identifier sequence in the reflected optical signal of the third service optical signal. The processing unit 603 can also be used to perform peak detection on the fractional Fourier transform spectrum to obtain a signal intensity variation curve of the third identifier sequence. The signal intensity variation curve can be used for fault detection in the optical fiber link between the third node and the first node.

[0141] It should be noted that all relevant content of each step involved in the above method embodiments can be referenced from the functional description of the corresponding functional module, and will not be repeated here. Since the communication device 60 provided in this embodiment can execute the above fiber optic link fault detection method, the technical effects it can obtain can be referred to the above method embodiments, and will not be repeated here.

[0142] When a communication device implements any of the aforementioned fiber optic link fault detection methods through software, the communication device and its various units can also be software modules. The aforementioned fiber optic link fault detection method is implemented by the processor calling the software module. The processor can be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or a programmable logic device (PLD). The PLD can be a complex programmable logical device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0143] A more detailed description of the aforementioned communication device can be found in the embodiments shown in the foregoing figures, and will not be repeated here. It is understood that the communication device shown in the foregoing figures is merely an example provided for this embodiment, and the communication device may include more or fewer units depending on the online process or service; this application does not limit this.

[0144] When a communication device is implemented in hardware, this hardware can be implemented using a processor or a chip. A chip includes interface circuitry and control circuitry. The interface circuitry is used to receive data from other devices besides the processor and transmit it to the control circuitry, or to send data from the control circuitry to other devices besides the processor.

[0145] The control circuit and interface circuit are used, through logic circuits or executable code instructions, to implement any of the possible implementation methods in the above embodiments. The beneficial effects can be found in the descriptions of any aspect of the above embodiments, and will not be repeated here.

[0146] It is understood that the processor in the embodiments of this application may be a CPU, a neural processing unit (NPU), or a graphics processing unit (GPU), or it may be other general-purpose processors, digital signal processors (DSPs), ASICs, FPGAs, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor.

[0147] in addition, Figure 6The communication device 60 shown can also be implemented by the communication device 70, such as... Figure 7 As shown, Figure 7 This application provides a schematic diagram of another communication device 70, which includes a memory 710 and at least one processor 720. The processor 720 can implement the fiber optic link fault detection method provided in the above embodiments. The memory 710 is used to store software instructions corresponding to the fiber optic link fault detection method. As an optional implementation, in hardware implementation, the communication device 70 can refer to a chip or chip system encapsulating one or more processors 720. For example, when the communication device 70 is used to implement the method steps in the above embodiments, the processor 720 included in the communication device 70 executes the steps of the method and its possible sub-steps. In an optional case, the communication device 70 may further include a communication interface 730, which can be used to send and receive data. Optionally, the communication interface 730 can be implemented through an interface circuit included in the communication device 70.

[0148] In the embodiments of this application, the communication interface 730, the processor 720 and the memory 710 can be connected via a bus 740, which can be divided into an address bus, a data bus, a control bus, etc.

[0149] It is worth noting that the communication device 70 can also perform Figure 6 The functions of the communication device 60 shown are not described in detail here.

[0150] The communication device 70 provided in this embodiment can be any of the aforementioned devices, such as the first node, the second node, or the third node.

[0151] The method steps in the embodiments of this application can also be implemented by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network device or a terminal device. Alternatively, the processor and storage medium can exist as discrete components in the network device or terminal device.

[0152] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video disc (DVD); or it can be a semiconductor medium, such as a solid-state drive (SSD).

[0153] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0154] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates an "or" relationship between the preceding and following related objects; in the formulas of this application, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0155] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic.

Claims

1. A method for detecting fiber optic link faults, characterized in that, The method includes: The first node sends a first service optical signal to the second node, wherein the first service optical signal includes a first identifier sequence, which is obtained by a p-order fractional Fourier transform of a first constant sequence; The first node acquires the received optical signal, which includes the reflected optical signal generated by back Rayleigh scattering during the transmission of the first service optical signal in the optical fiber; The first node performs a (1-p)-order fractional Fourier transform on the received optical signal to obtain a fractional Fourier transform spectrum; wherein, the peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal; The first node performs peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the first identifier sequence; wherein, the signal intensity change curve is used to detect faults in the optical fiber link between the first node and the second node.

2. The method according to claim 1, characterized in that, The first node performs a p-order fractional Fourier transform on the first constant sequence, which is achieved by the following formula: Where x(t) is the first constant sequence, X p (u) represents the first identifier sequence, and p represents the order of the fractional Fourier transform.

3. The method according to claim 1 or 2, characterized in that, The first node performs a (1-p)-order fractional Fourier transform on the received optical signal, which is achieved by the following formula: Where y(t) is the received optical signal, Y (1-p) (u) represents the fractional Fourier transform spectrum, and (1-p) represents the order of the fractional Fourier transform.

4. The method according to any one of claims 1-3, characterized in that, The received optical signal also includes a second service optical signal from the second node.

5. The method according to claim 4, characterized in that, The second service optical signal includes a second identifier sequence, which is obtained by performing a q-order fractional Fourier transform on a second constant sequence, where q is not equal to p.

6. The method according to claim 4 or 5, characterized in that, The first node is connected to multiple nodes via an optical splitter, including the second node; the service optical signals sent by the multiple nodes are transmitted to the first node in a time-division multiplexing manner.

7. The method according to claim 6, characterized in that, The plurality of nodes also includes a third node; the received optical signal also includes a third service optical signal from the third node, the third service optical signal including a third identifier sequence; wherein the third identifier sequence is obtained by r-order fractional Fourier transform of a third constant sequence, where r is not equal to p and r is not equal to q.

8. The method according to claim 7, characterized in that, The first node is an optical line terminal (OLT), and the second and third nodes are optical network units (ONUs); the method further includes: The first node sends a first OMCI message or a first PLOAM message to the second node, the first OMCI message or the first PLOAM message being used to indicate the order q; The first node sends a second OMCI message or a second PLOAM message to the third node, the second OMCI message or the second PLOAM message being used to indicate the order r.

9. An optical communication system, characterized in that, The optical communication system includes a first node and a second node; The first node is used to send a first service optical signal to the second node, wherein the first service optical signal includes a first identification sequence, and the first identification sequence is obtained by passing a first constant sequence through a p-order fractional Fourier transform; The first node is also used to acquire received optical signals, including reflected optical signals generated by back Rayleigh scattering during the transmission of the first service optical signal in the optical fiber. The first node is further configured to perform a (1-p)-order fractional Fourier transform on the received optical signal acquired by the first node to obtain a fractional Fourier transform spectrum; wherein, the peak value of the fractional Fourier transform spectrum corresponds to the energy of the first identifier sequence in the reflected optical signal of the first service optical signal; The first node is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the first identifier sequence; wherein, the signal intensity change curve is used to detect faults in the optical fiber link between the first node and the second node.

10. The optical communication system according to claim 9, characterized in that, The second node is also used to send a second service optical signal to the first node, and the received optical signal obtained by the first node also includes the second service optical signal from the second node.

11. The optical communication system according to claim 10, characterized in that, The second service optical signal includes a second identifier sequence, which is obtained by performing a q-order fractional Fourier transform on a second constant sequence, where q is not equal to p.

12. The optical communication system according to claim 11, characterized in that, The second node is also used to acquire the received optical signal, which includes the reflected optical signal generated by back Rayleigh scattering during the transmission of the second service optical signal in the optical fiber. The second node is also used to perform a (1-q)-order fractional Fourier transform on the received optical signal acquired by the second node to obtain a fractional Fourier transform spectrum; wherein, the peak value of the fractional Fourier transform spectrum corresponds to the energy of the second identifier sequence in the reflected optical signal of the second service optical signal; The second node is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the second identifier sequence; wherein, the signal intensity change curve is used to detect faults in the optical fiber link between the second node and the first node.

13. The optical communication system according to any one of claims 10-12, characterized in that, The first node is connected to multiple nodes via an optical splitter, including the second node; the service optical signals sent by the multiple nodes are transmitted to the first node in a time-division multiplexing manner.

14. The optical communication system according to claim 13, characterized in that, The plurality of nodes also includes a third node; The third node is used to send a third service optical signal to the first node. The third service optical signal includes a third identifier sequence. The third identifier sequence is obtained by performing an r-order fractional Fourier transform on a third constant sequence, where r is not equal to p and r is not equal to q.

15. The optical communication system according to claim 14, characterized in that, The third node is also used to acquire received optical signals, which include the first service optical signal and the reflected optical signal generated by back Rayleigh scattering during the transmission of the third service optical signal in the optical fiber. The third node is also used to perform a (1-r)-order fractional Fourier transform on the received optical signal acquired by the third node to obtain a fractional Fourier transform spectrum; wherein, the peak value of the fractional Fourier transform spectrum corresponds to the energy of the third identifier sequence in the reflected optical signal of the third service optical signal. The third node is also used to perform peak detection on the fractional Fourier transform spectrum to obtain the signal intensity change curve of the third identifier sequence; wherein, the signal intensity change curve is used to detect faults in the optical fiber link between the third node and the first node.

16. A communication device, characterized in that, The communication device includes: a communication interface and a processor; The communication interface is used to perform the sending and receiving actions in the method of any one of claims 1-8, and the processor is used to perform the processing actions in the method of any one of claims 1-8.

17. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1-8.

Images