Environmental disturbance monitoring method for submarine cable system and submarine cable system

Abstract

The present application relates to the technical field of submarine cable system monitoring, and provides a method for monitoring environmental disturbances of a submarine cable system and a submarine cable system, the method comprising obtaining monitoring information of the submarine cable system; determining a first target repeater in the submarine cable system according to the monitoring information; controlling the first target optical switch in the first target repeater to be turned on, controlling the DAS device to send a detection optical signal to the submarine cable optical fiber; controlling the DAS device to receive a backscattered optical signal returned by the first target optical switch; and determining environmental disturbance information of the submarine cable optical fiber according to the backscattered optical signal. In this way, by controlling the conduction and closure of the optical switch in the first target repeater in a specific area, the backscattered optical signal of the detection optical signal can pass through the loop optical path of the first target repeater, thereby realizing monitoring of a specific area, improving the response frequency of a long-distance repeater submarine cable system, comprehensively obtaining environmental disturbance information of the surrounding environment of the submarine cable optical fiber, and improving the accuracy of identifying marine events.

Description

Technical Field

[0001] The present application relates to the technical field of submarine cable monitoring, and in particular to an environmental disturbance monitoring method for a submarine cable system and a submarine cable system. Background Art

[0002] Distributed fiber acoustic sensing (DAS) technology is based on the principle of Rayleigh scattering and uses the sensitivity of optical fiber to sound (vibration) to achieve perception functions.

[0003] In a repeated cable system, since the detection light of DAS technology adopts the mode of pulsed light, the round-trip time of pulsed light in the optical fiber can limit the emission frequency of DAS detection light pulses and the frequency of disturbance signals that can be monitored. However, the round-trip time of pulsed light is determined by the time it takes for the pulsed light to pass through the entire submarine cable fiber. In a long-distance submarine cable system, the round-trip time of DAS detection light is long, resulting in a lower emission frequency of DAS detection light pulses, which makes the submarine cable system smaller in the frequency range that can be monitored for disturbances in the surrounding environment, affecting the perception of submarine cable events. Summary of the invention

[0004] In order to solve the above problems, the present application provides an environmental disturbance monitoring method and a submarine cable system for a submarine cable system, which can improve the response frequency of a long-distance relay submarine cable system, thereby comprehensively acquiring environmental disturbance information of the environment around the submarine cable optical fiber and improving the accuracy of sensing and identifying marine events.

[0005] In order to achieve the above-mentioned objectives, in a first aspect, the present application provides a method for monitoring environmental disturbances of a submarine cable system, the method comprising: obtaining monitoring information of the submarine cable system; determining a first target repeater in the submarine cable system according to the monitoring information; controlling a first target optical switch in the first target repeater to be turned on, wherein the first target optical switch is an optical switch of a loopback optical path in the first target repeater; controlling a DAS device to send a detection optical signal to the submarine cable optical fiber; controlling the DAS device to receive and analyze a backscattered optical signal returned through the first target optical switch; the backscattered optical signal is an optical signal generated by the detection optical signal during the forward transmission of the submarine cable optical fiber; and determining environmental disturbance information of the submarine cable system according to the detection backscattered light signal.

[0006] According to the above embodiment, monitoring information of the submarine cable system is obtained; the first target repeater in the submarine cable system is determined according to the monitoring information; the first target optical switch in the first target repeater is controlled to be turned on, the DAS device is controlled to send a detection optical signal to the submarine cable optical fiber, and the backscattered optical signal returned by the first target optical switch is received and analyzed; the environmental disturbance information of the submarine cable system is determined according to the backscattered optical signal. In this way, by controlling the conduction and closure of the optical switch in the first target repeater in a specific area, the backscattered optical signal generated by the detection optical signal can only pass through the loopback optical path of the first target repeater, thereby realizing monitoring of a specific area, improving the response frequency of the submarine cable system, and further improving the accuracy of the environmental disturbance information of the submarine cable system.

[0007] In an optional implementation, the environmental disturbance information of the submarine cable optical fiber is determined based on the backscattered light signal, including: processing the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; extracting the disturbance characteristics of the time domain signal and / or the frequency domain signal, the disturbance characteristics including at least one of time, amplitude, phase and frequency; and determining the environmental disturbance information of the submarine cable optical fiber based on the disturbance characteristics. In this way, the environmental disturbance information of the submarine cable system is determined based on the backscattered light signal, thereby accurately sensing marine events.

[0008] In an optional implementation, the monitoring information includes information about the area to be monitored and information about the event to be monitored; determining the first target repeater in the submarine cable system according to the monitoring information includes: determining the range to be monitored according to the information about the area to be monitored; determining the maximum monitoring range according to the information about the event to be monitored and the range to be monitored; and determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range. In this way, the sensing span can be determined according to the information about the area to be monitored and the information about the event to be monitored, and then the first target repeater in the sensing span can be determined, so as to control the optical switch in the first target repeater.

[0009] In an optional implementation, according to the range to be monitored and the maximum monitoring range, determining the first target repeater within the range to be monitored includes: in response to the range to be monitored being less than or equal to the maximum monitoring range, taking each repeater within the range to be monitored as the first target repeater. In this way, when the range to be monitored is less than the maximum monitoring range, only one detection optical signal needs to be sent to the range to be monitored to monitor the submarine cable event.

[0010] In an optional implementation, the first target repeater in the range to be monitored is determined based on the range to be monitored and the maximum monitoring range, and further includes: in response to the range to be monitored being larger than the maximum monitoring range, the range to be monitored is divided according to the maximum monitoring range to obtain N sub-ranges to be monitored; each sub-range to be monitored is less than or equal to the maximum monitoring range, and N is a positive integer greater than or equal to 2; each repeater in the range to be monitored is used as the first target repeater, and the repeater in each sub-range to be monitored is used as a target sub-repeater. In this way, when the range to be monitored is larger than the maximum monitoring range, in order to ensure the accuracy of the monitoring event, the range to be monitored can be segmented, and the environmental disturbance information of the environment surrounding the submarine cable system can be obtained separately. Under the premise of sacrificing timeliness, the monitorable spatial range can also be expanded without affecting the monitoring disturbance frequency range.

[0011] In an optional implementation, the environmental disturbance monitoring method of the submarine cable system further includes: traversing and executing the following steps until i=N, where i is a positive integer greater than 0: controlling the i-th optical switch in the i-th sub-range to be monitored to be turned on at the same time, controlling the DAS device to send the i-th detection optical signal to the submarine cable optical fiber, and controlling the DAS device to receive and analyze the i-th backscattered optical signal passing through each i-th optical switch; wherein the i-th optical switch is the optical switch of the loopback optical path of each target sub-repeater in the i-th sub-range to be monitored; after the i-th backscattered optical signal passes through all the i-th optical switches, controlling all the i-th optical switches to be disconnected at the same time. In this way, by controlling the optical switch in each sub-range to be monitored, the backscattered light can be passed in segments, and the monitorable spatial range can be expanded without affecting the monitoring disturbance frequency range, thereby improving the accuracy of submarine cable event monitoring.

[0012] In an optional implementation, the environmental disturbance monitoring method of the submarine cable system further includes: setting multiple time slices; dividing the submarine cable optical fiber according to the number of time slices to obtain multiple submarine cable spans, wherein each submarine cable span includes at least one second target repeater, and the number of time slices is the same as the number of submarine cable spans; in each time slice, controlling the second target optical switch in the submarine cable span corresponding to the time slice to be turned on at the same time, wherein the second target optical switch is the optical switch of the loopback optical path of the second target repeater in the submarine cable span; controlling the DAS device to send a detection optical signal to the submarine cable optical fiber, and controlling the DAS device to receive and analyze the backscattered optical signal returned by each second target optical switch passing through the submarine cable span; determining the environmental disturbance information of the submarine cable span according to the backscattered optical signal. In this way, multiple time slices can be set to complete the monitoring of the entire submarine cable system.

[0013] In a second aspect, the present application provides a submarine cable system, comprising: a submarine cable optical fiber, used for transmission and sensing of optical signals; at least one repeater for amplifying optical signals, the repeater being provided with at least one loopback optical path, and the loopback optical path being provided with an optical switch; a DAS device, used for sending a detection optical signal and receiving and analyzing a backscattered optical signal; the backscattered optical signal is an optical signal generated during the forward transmission of the detection optical signal in the submarine cable optical fiber; a controller, used for obtaining monitoring information for monitoring the submarine cable system; determining a first target repeater in the submarine cable system according to the monitoring information; controlling a first target optical switch of the first target repeater to be turned on; wherein the first target optical switch is an optical switch of the loopback optical path in each first target repeater; controlling the DAS device to send a detection optical signal to the submarine cable optical fiber; controlling the DAS device to receive and analyze the backscattered optical signal returned through the first target optical switch; and determining environmental disturbance information of the submarine cable optical fiber according to the backscattered optical signal.

[0014] In an optional embodiment, the controller is also used to process the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; extract disturbance characteristics of the time domain signal and / or the frequency domain signal, the disturbance characteristics including at least one of time, amplitude, phase and frequency; and determine the environmental disturbance information of the submarine cable optical fiber based on the disturbance characteristics.

[0015] In an optional embodiment, the controller is also used to determine the monitored range based on the monitored area information; determine the maximum monitoring range based on the monitored event information and the monitored range; and determine the first target repeater within the monitored range based on the monitored range and the maximum monitoring range.

[0016] It can be understood that the beneficial effects that can be achieved by the technical solution of the second aspect provided above can refer to the beneficial effects in the first aspect and any optional implementation method thereof, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A schematic diagram of the structure of a submarine cable system with repeaters that uses DAS technology;

[0019] Figure 2 A schematic diagram of the structure of another submarine cable system with repeaters that uses DAS technology;

[0020] Figure 3 A schematic diagram of a flow chart of an environmental disturbance monitoring method for a submarine cable system provided in an embodiment of the present application;

[0021] Figure 4 A schematic diagram of the structure of a sensor span of a submarine cable system provided in an embodiment of the present application having a repeater;

[0022] Figure 5 A schematic diagram of a structure of a submarine cable system having a plurality of repeaters in a sensing span provided in an embodiment of the present application;

[0023] Figure 6 A schematic diagram of the structure of a repeater provided in an embodiment of the present application;

[0024] Figure 7a A schematic diagram of a structure in which an optical switch in a repeater provided in an embodiment of the present application is disconnected;

[0025] Figure 7b A schematic diagram of the structure of an optical switch being turned on in a repeater provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, other embodiments obtained by ordinary technicians in this field without making creative work all belong to the protection scope of the present application.

[0027] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0028] In addition, in the present application, directional terms such as "upper", "lower", "inner" and "outer" are defined relative to the orientation of the components schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to the changes in the orientation of the components placed in the drawings.

[0029] To facilitate understanding of the solution, the following explains the relevant terms:

[0030] Submarine cable system: It is an infrastructure used for transoceanic and transsea communications, which mainly relies on optical fiber cables laid on the seabed for data transmission. Submarine cable systems can be divided into two categories according to whether repeaters are used to amplify the signal: repeated cable system and repeaterless cable system.

[0031] Repeater-free submarine cable system: By enhancing the transmission performance of optical fiber, the signal can be amplified and regenerated over a longer distance without the need for repeater equipment.

[0032] Repeater submarine cable system: refers to a communication cable with repeaters installed at certain distances on the submarine cable.

[0033] Repeater: It is used to enhance the signal in the submarine cable optical fiber and compensate for the signal attenuation during long-distance transmission.

[0034] Distributed fiber acoustic sensing technology (DAS): Based on the principle of Rayleigh scattering, it uses the sensitivity of optical fiber to sound (vibration) to achieve perception function.

[0035] DAS technology is applied to submarine cable systems, and existing optical fibers can be used to sense events around the submarine cable, including but not limited to earthquakes, ocean noise, waves, ship activities, etc. At present, DAS technology is widely used in non-repeater submarine cable systems, which can use optical fiber direct connection systems or optical fiber systems using Raman amplification. The characteristics of these systems are that there are no repeaters, so DAS technology can be directly applied to these optical fiber links without considering the impact of repeaters on signals.

[0036] Figure 1 A schematic diagram of the structure of a submarine cable system with repeaters that uses DAS technology.

[0037] However, DAS technology is rarely applied to submarine cable systems with relays, because in submarine cable systems with relays, underwater optical repeaters generally provide optical fiber loopback paths for coherent optical time domain reflectometers (COTDR) to locate optical fiber faults. Figure 1 As shown, a submarine cable system with a relay may include a DAS device, a detection optical signal sent by the DAS device, and multiple repeaters. Each repeater includes a loopback optical path 1 and a loopback optical path 2. In order to meet the working requirements of COTDR, the loss of the loopback optical path is extremely large. The backscattered signal generated by the DAS detection light during the transmission of the submarine cable optical fiber is attenuated too much after returning through the loopback optical path, resulting in the DAS device being unable to analyze the signal normally. In some systems, in order to meet the requirements of communication service transmission and OTDR work, a dedicated single-pass optical filter is configured in the loopback optical path, resulting in the backscattered signal generated by the DAS detection light being blocked by the loopback optical path, and the DAS device cannot receive the signal.

[0038] In addition, in long-distance submarine cable systems with relays, the detection light signal sent by the DAS device adopts the mode of pulsed light. Due to the long transmission length of the submarine cable, the round-trip time of the pulsed light in the optical fiber is long. And the DAS device can only send the next detection light signal after receiving the backscattered light signal generated after the current detection light signal passes through the entire submarine cable. In this way, the long round-trip time of the pulsed light in the optical fiber limits the emission frequency of the DAS detection light pulse, thereby limiting the maximum monitoring frequency of the DAS device, and further limiting the DAS device's perception of events around the submarine cable optical fiber.

[0039] For example, the characteristic frequencies of common marine events are: earthquake: <100Hz; assault boat: 68.5Hz; sea wave: 3-9Hz. For a 15,000km relay submarine cable system, the transmission time of the detection light signal sent by the DAS equipment and the backscattered light it generates in the submarine cable fiber is about 0.15 seconds, and the theoretical maximum monitorable frequency of the submarine cable system is only about 3.5Hz. In other words, the DAS equipment can only sense events with a frequency within 3.5Hz, and cannot sense events beyond the maximum response frequency, such as earthquakes.

[0040] Figure 2 A schematic diagram of the structure of another submarine cable system with relays that uses DAS technology.

[0041] For the application of DAS in the submarine cable system with relays, such as Figure 2 As shown, we can also learn from the concept of wavelength division multiplexing in the communication system and adopt a solution of sending multiple detection wavelengths at the same time, so that the signals between each wavelength do not affect each other. Since each detection wavelength is only responsible for a section of the submarine cable area, the monitoring frequency range of the DAS equipment can be increased, and the frequency range of the environmental disturbance information of the submarine cable system can be obtained.

[0042] However, in multi-wavelength DAS equipment, each detection wavelength is only responsible for a section of the submarine cable area. With each additional wavelength, the number of devices at the transmitting end and the demodulating end of the equipment will increase proportionally, and the corresponding equipment cost will also increase exponentially based on the number of added wavelengths, making the cost of DAS equipment high. Furthermore, since the loopback wavelength of each repeater is different, the complexity of the repeater increases, which increases the manufacturing and implementation cost of the repeater.

[0043] In summary, in a submarine cable system with relays, the long round trip time of pulsed light in the optical fiber limits the emission frequency of DAS detection light pulses and the system response frequency, affecting the perception of submarine cable events. In addition, if wavelength division multiplexing is adopted, the cost of DAS equipment and the complexity and cost of optical repeaters will increase.

[0044] For long-distance submarine cable systems with relays, it may be that only a specific area actually needs to be detected by the DAS device. The loopback optical path of the underwater optical repeater in only the specific area can return the backscattered signal of the single-wavelength detection optical signal. The loopback optical path of the underwater optical repeater outside the specific area blocks the backscattered signal of the single-wavelength detection optical signal, that is, the backscattered signal cannot be returned. The DAS device can emit the next detection light pulse when the backscattered light signal passes through the underwater optical repeater in the specific area. The backscattered signal generated by the optical fiber line in the non-specific area cannot be returned to the DAS device through the loopback optical path. This can shorten the emission interval of the detection light signal, thereby increasing the frequency range of the DAS monitoring submarine cable system.

[0045] In view of this, Figure 3 A schematic diagram of a process flow of an environmental disturbance monitoring method for a submarine cable system provided in an embodiment of the present application. Figure 3 As shown, the method is applied to a submarine cable system, which may include a submarine cable optical fiber, multiple repeaters, and a DAS device. Here, multiple repeaters may be evenly distributed in the submarine cable optical fiber, and the DAS device adopts distributed acoustic wave sensing technology, and may use the optical fiber as a sensor to monitor the sound waves or vibrations in the environment surrounding the submarine cable. The method includes the following steps:

[0046] S100: Acquire monitoring information of the submarine cable system.

[0047] In some embodiments, the user inputs monitoring information for monitoring the submarine cable system through a user interface in the submarine cable system. The monitoring information can be used to select a monitoring area, set a time-sharing traversal strategy, set a monitoring frequency range, and a fault request.

[0048] S200: Determine a first target repeater in the submarine cable system according to the monitoring information.

[0049] In some embodiments, the monitoring information may include information on the area to be monitored and information on events to be monitored, wherein the information on the area to be monitored includes the specific geographical range that needs to be monitored or a specific section on the submarine cable, and the information on events to be monitored includes specific types of events that need to be monitored and the characteristic frequencies corresponding to the monitored events, the sampling frequencies of the DAS equipment, etc. The monitored events may include earthquakes, ship activities, etc.

[0050] In some embodiments, step S200 may specifically include: determining the range to be monitored according to the information of the area to be monitored; determining the maximum monitoring range according to the information of the event to be monitored; and determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range.

[0051] In some embodiments, the monitored range of the submarine cable system, i.e., the specific range to be monitored, can be determined based on the monitored area information. The monitored area information may include location information to be monitored. The monitored area information may be converted into specific location coordinates along the submarine cable, such as longitude and latitude coordinates. Exemplarily, when the monitored area information in the monitoring information can determine the longitude and latitude range of a certain section of the submarine cable, the submarine cable system may identify the corresponding submarine cable section based on the longitude and latitude range.

[0052] In some embodiments, the minimum sampling frequency of the DAS device can be determined according to the information of the event to be monitored, such as the type of the event to be monitored and its corresponding characteristic frequency, and the maximum monitoring range can be calculated according to the minimum sampling frequency and the propagation speed of light in the light beam. Here, different monitoring events correspond to different monitoring frequencies. For example, monitoring earthquakes requires a larger monitoring frequency to capture a wide range of seismic waves, and monitoring ship activities requires a smaller monitoring frequency range.

[0053] In some embodiments, the minimum sampling frequency of the DAS device can be determined according to the characteristic frequency corresponding to the event to be monitored. According to the Nyquist sampling theorem, the sampling frequency must be at least twice the highest frequency component of the signal, that is, the minimum sampling frequency is twice the characteristic frequency. Then, the maximum monitoring range can be determined according to the ratio of the propagation speed of light in the optical fiber to the minimum sampling frequency.

[0054] For example, the event information to be monitored is an earthquake event, and the maximum characteristic frequency corresponding to the earthquake event is 100 Hz. The propagation speed of light in an optical fiber is approximately m / s, the maximum monitoring range of the DAS equipment for monitoring earthquake events through the submarine cable system is 500km. At this time, the corresponding submarine cable section can be determined based on the information of the area to be monitored.

[0055] Further, after determining the range to be monitored and the maximum monitoring range, the sensing span of the submarine cable system can be determined in combination with the information of the range to be monitored and the maximum monitoring range, and the repeater in the sensing span can be used as the first target repeater. Specifically, a repeater that meets the conditions in the range to be monitored can be selected as the first target repeater.

[0056] Figure 4 A schematic diagram of a structure of a sensing span of a submarine cable system provided in an embodiment of the present application having a repeater. When there is only one submarine cable span determined according to the range to be monitored and the maximum monitoring range, the repeater in the span can be used as the first target repeater. For example, Figure 4 As shown, when the first target repeater in the submarine cable span determined according to the range to be monitored and the maximum monitoring range is repeater x, repeater x is used as the first target repeater.

[0057] Figure 5A schematic diagram of the structure of a submarine cable system having a plurality of repeaters in a sensing span provided in an embodiment of the present application.

[0058] In some embodiments, for the application of submarine cable systems, there are specific range requirements for the response frequency, and the solution of selecting the DAS signal loopback wavelength in the loopback optical path of only one underwater optical relay may far exceed the frequency range requirements of submarine cable customers. In other words, if the DAS backscattered optical signal is selected in the loopback optical path of only a single underwater optical repeater, the monitoring frequency range will be too wide, far exceeding the customer's needs.

[0059] In this regard, we can select several adjacent repeaters within the span according to the frequency range requirements of the submarine cable customers, increase the submarine cable span range sensed by the DAS, and capture more environmental changes and abnormal situations. Figure 5 As shown, the repeater x and the repeater x+1 in the sensing span are both first target repeaters. In this way, setting a plurality of first target repeaters can increase the monitoring range, more effectively monitor the potential security threats around the sensing span, and improve security.

[0060] S300: Controlling a first target optical switch in a first target repeater to turn on.

[0061] In some embodiments, when the DAS device determines the range to be monitored and the maximum monitoring range, the DAS device may query the geographic information database of the submarine cable system to find out the IDs or numbers of all repeaters in the area to be monitored.

[0062] The DAS device may generate a control instruction including a range to be monitored and ID information of a first target repeater within the range to be monitored, and send the control instruction to the submarine cable system.

[0063] The submarine cable system receives the control instruction, determines the area to be monitored and the first target repeater of the area to be monitored according to the control instruction, and controls the first optical switch in the first target repeater to be turned on. The first target optical switch is an optical switch of the loopback optical path in the first target repeater.

[0064] Figure 6 A schematic diagram of the structure of a repeater provided in an embodiment of the present application.

[0065] The DAS device can send the detection light signal from left to right, or from right to left. Figure 6 As shown, each repeater has two loop-back optical paths, namely, loop-back optical path 1 and loop-back optical path 2, and each loop-back optical path has an optical switch, such as Figure 6As shown in the figure, the optical switch a and the optical switch b can be set from the output end to the input end of the repeater, or can be set from the output end to the output end of the repeater. When the DAS device sends a detection light signal from left to right, the backscattered signal of the detection light signal returns to the DAS device through the optical switch b of the loopback optical path 2. When the DAS device sends a detection light signal from right to left, the backscattered signal of the detection light signal returns to the DAS device through the optical switch a of the loopback optical path 1.

[0066] When the submarine cable system is used to monitor a submarine cable span in a specific area, the optical switches of all repeaters in the submarine cable optical fiber are in the disconnected state, so that the submarine cable system can control the optical switches of the repeaters of the submarine cable optical fiber in the specific span to be turned on after receiving a control instruction.

[0067] In some embodiments, the optical switch can receive a control command from the submarine cable system to change the state to on or off. The present application does not limit the form of the optical switch, including 1×1 optical switch, 2×2 bypass optical switch, or other optical switches such as mechanical optical switch, electromechanical optical switch, electro-optical optical switch, acoustic-electric optical switch, etc.

[0068] Figure 7a and Figure 7b They are schematic diagrams of the structure of the optical switch being disconnected and turned on in the repeater provided in the embodiments of the present application.

[0069] like Figure 7a As shown, the optical switch is set from the output end to the input end of the repeater. The optical switch may include an input port A and an output port B. The connection path between the input port A and the output port B of the optical switch is disconnected. At this time, the optical switch is disconnected and the loop optical path is in a disconnected state. Figure 7b As shown, the input port A and the output port B of the optical switch are connected, so that the optical switch is turned on, the loopback optical path is in the on state, and is filtered by the bandpass filter, and the span corresponding to the current optical repeater can be sensed by the DAS device.

[0070] S400: Control the DAS device to send a detection optical signal to the submarine cable optical fiber.

[0071] In some embodiments, after the first target optical switch is turned on, the submarine cable system sends an instruction to the DAS to start the detection optical signal, and the DAS device can send the detection optical signal to the submarine cable optical fiber according to the instruction. Here, the detection optical signal is a laser pulse, and the laser pulse will propagate along the submarine cable optical fiber.

[0072] S500: Control the DAS device to receive and analyze the backscattered light signal returned by the first target optical switch.

[0073] In some embodiments, when the laser pulse propagates in the optical fiber, Rayleigh scattering may occur due to the inhomogeneity of the optical fiber material of the submarine cable. Rayleigh scattering will cause a small number of photons to propagate in the reverse direction, forming a backscattered light signal, that is, the backscattered light signal is the light signal generated by the detection light signal during the forward transmission of the submarine cable optical fiber.

[0074] When the first target optical switch is turned on, when the detection optical signal passes through the first target repeater, the backscattered optical signal generated by the adjacent submarine cable span optical fiber will pass through the loopback optical path of the first target repeater and return to the DAS device.

[0075] In this way, the DAS device receives the sensor signal returned by the submarine cable span in the selected area and performs signal analysis. The loopback optical paths of other optical repeaters block the backscattered signal generated by the detection light signal sent by the DAS device during transmission in the submarine cable optical fiber.

[0076] In this way, since only the optical switch of the loop-back optical path corresponding to the specific area is turned on and the optical switches of the other loop-back optical paths are turned off, the DAS device can receive the backscattered light signal returned after passing through the loop-back optical path corresponding to the specific area, and the backscattered light generated by the submarine cable optical fiber in the non-specific area cannot return to the DAS device through the loop-back optical path. Therefore, the DAS device can increase the emission frequency of the detection light pulse accordingly, and the backscattered signals generated in the submarine cable optical fiber can be separated in time, so that the DAS device can receive and analyze them normally.

[0077] S600: Determine environmental disturbance information of the submarine cable optical fiber according to the backscattered light signal.

[0078] Here, by analyzing the backscattered light signal, the environmental disturbance information of the submarine cable optical fiber can be obtained, that is, the specific disturbance conditions of the environment around the submarine cable optical fiber, such as seabed earthquakes, marine biological activities, etc.

[0079] In some embodiments, step S600 may include: processing the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; extracting disturbance characteristics of the time domain signal and / or the frequency domain signal, the disturbance characteristics including at least one of time, amplitude, phase and frequency; and determining the environmental disturbance information of the submarine cable optical fiber based on the disturbance characteristics.

[0080] In some embodiments, the DAS device may convert the backscattered light signal into an electrical signal, and pre-process the electrical signal using digital signal processing technology to remove noise and improve the signal-to-noise ratio of the electrical signal. Preprocessing may include denoising, amplification, and filtering. Then, the pre-processed time domain signal may be converted into a frequency domain signal using a Fourier transform algorithm. Then, disturbance features related to disturbances in the environment surrounding the submarine cable are extracted from the frequency domain signal, such as amplitude changes, phase changes, frequency changes, etc. Afterwards, a neural network model or a machine learning algorithm may be used to identify and classify the disturbance features to obtain environmental disturbance information of the submarine cable optical fiber. Furthermore, environmental disturbance information may be determined in combination with known parameters of the optical fiber (such as length, refractive index, etc.).

[0081] According to the above embodiment, monitoring information of the submarine cable system is obtained; the first target repeater in the submarine cable system is determined according to the monitoring information; the first target optical switch in the first target repeater is controlled to be turned on, wherein the first target optical switch is an optical switch of the loopback optical path in the first target repeater; the DAS device is controlled to send a detection optical signal to the submarine cable optical fiber; the DAS device is controlled to receive the backscattered optical signal returned by the first target optical switch; and the environmental disturbance information of the submarine cable optical fiber is determined according to the backscattered optical signal. In this way, by controlling the conduction and closure of the optical switch in the first target repeater in a specific area, the backscattered optical signal of the detection optical signal can only pass through the loopback optical path of the first target repeater, thereby realizing monitoring of a specific area, improving the sensor response frequency of the submarine cable system, and further improving the monitoring capability of identifying and determining the environmental disturbance information of the submarine cable system.

[0082] In some embodiments, the step of determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range may include:

[0083] S1: In response to the range to be monitored being less than or equal to the maximum monitoring range, each repeater within the range to be monitored is taken as a first target repeater.

[0084] In some embodiments, if the range to be monitored is less than or equal to the maximum monitoring range, each repeater within the range to be monitored is used as the first target repeater. For example, if the range to be monitored is 400-500km and the maximum monitoring range is 500km, then repeaters within the range of 400km to 500km are searched. Assuming there are two repeaters within the range, these two repeaters are used as the first target repeaters.

[0085] S2: In response to the range to be monitored being larger than the maximum monitoring range, the range to be monitored is divided according to the maximum monitoring range to obtain N sub-ranges to be monitored, each repeater in the range to be monitored is used as a first target repeater, and each repeater in each sub-range to be monitored is used as a target sub-repeater.

[0086] In some embodiments, each sub-range to be monitored obtained by division is less than or equal to the maximum monitoring range, and N is a positive integer greater than or equal to 2. In this way, in response to the situation where the range to be monitored is larger than the maximum monitoring range, by dividing the range to be monitored into multiple sub-ranges for segmented monitoring, it can be ensured that each sub-range is within the maximum monitoring range and each sub-range can be effectively monitored.

[0087] For example, assuming that the range to be monitored is 100km (from 500km to 600km) and the maximum monitoring range is 50km, 500km to 600km is divided into two sub-ranges according to the maximum monitoring range: sub-range 1: 500km to 550km, sub-range 2: 550km to 600km. The repeaters in the range from 500km to 600km are taken as the first target repeaters, and the first target repeaters corresponding to sub-range 1: 500km to 550km and sub-range 2: 550km to 600km are taken as target sub-repeaters.

[0088] After step S2, executing steps S300-S500 may specifically include:

[0089] Steps S301-S304 are traversed and executed until i=N, where i is a positive integer greater than 0:

[0090] S301: Control the i-th optical switches in the i-th sub-range to be monitored to be turned on simultaneously.

[0091] Exemplarily, the submarine cable system first controls all first optical switches in the first sub-range to be monitored after segmentation to be turned on.

[0092] S302: Control the DAS device to send the i-th detection optical signal to the submarine cable optical fiber.

[0093] Exemplarily, when the first optical switch is turned on, the submarine cable system sends an instruction to start the detection optical signal to the DAS device, and after receiving the instruction, the DAS device sends the first detection optical signal to the submarine cable optical fiber.

[0094] S303: Control the DAS device to receive and analyze the i-th backscattered light signal passing through each i-th optical switch.

[0095] Exemplarily, the first optical switch is an optical switch of a loopback optical path of each target sub-repeater in the first sub-range to be monitored. The DAS device can receive the first backscattered optical signal returned by each first optical switch.

[0096] S304: Control all the i-th optical switches to be turned off simultaneously.

[0097] Exemplarily, after the DAS device receives the first backscattering signal of the first detection light passing through all the first optical switches, the DAS device sends an optical switch closing instruction to the submarine cable system. After receiving the instruction, the submarine cable system simultaneously turns off the first optical switches.

[0098] Furthermore, after the first optical switch is disconnected, the submarine cable system controls the second optical switch in the second sub-range to be monitored to be turned on, and controls the DAS device to send a second detection optical signal, and receives a second backscattered signal returned by all second optical switches. At this time, the submarine cable system controls the second optical switch to be disconnected, and executes the above steps in a loop until all sub-ranges to be monitored are traversed.

[0099] In some embodiments, the submarine cable system may also be traversed in time division to monitor the submarine cable time around the entire submarine cable optical fiber. The step of traversing the submarine cable system in time division may include:

[0100] S701: Set multiple time slices.

[0101] Here, multiple time slices can be set according to monitoring requirements, and each time slice represents a monitoring period within a period of time.

[0102] S702: Divide the submarine cable optical fiber according to the number of time slices to obtain multiple submarine cable spans.

[0103] Here, each submarine cable span includes at least one second target repeater, and the number of time slices is the same as the number of submarine cable spans.

[0104] S703: In each time slot, control the second target optical switches in the submarine cable span corresponding to the time slot to be turned on simultaneously.

[0105] Here, the second target optical switch is an optical switch of the loop optical path of the second target repeater in the submarine cable span. In this time slice, the second target optical switches in the span are controlled to be turned on simultaneously so that the backscattered signal of the detection optical signal can only pass through the span.

[0106] S704: Control the DAS device to send a detection optical signal to the submarine cable optical fiber, and control the DAS device to receive and analyze the backscattered optical signal returned by each second target optical switch passing through the submarine cable span.

[0107] Here, a detection optical signal is sent to the submarine cable optical fiber, and a backscattered signal returned through the second target optical switch is received and analyzed, so that the span can be monitored.

[0108] S705: Determine environmental disturbance information of the submarine cable span according to the backscattered light signal.

[0109] Here, the environmental disturbance information of the submarine cable span can be determined based on the backscattered light signal passing through the span.

[0110] According to the above embodiment, the DAS device only senses a specific span within a time slice, and the DAS device traverses different underwater spans of the entire submarine cable line in time, which can improve the monitoring range of the submarine cable system by the DAS.

[0111] According to the above embodiment, through time-sharing traversal, the monitoring of the entire submarine cable system or key areas of concern can be achieved without affecting the monitoring frequency range of the submarine cable system by the DAS equipment. For systems that need to monitor the entire submarine cable optical fiber, time-sharing traversal can meet the monitoring requirements of the entire submarine cable system. And by increasing the number of time slices to complete the control of each loop optical path, each loop optical path only needs to complete the state switching in a short time to achieve the monitoring of the entire submarine cable system, which can improve resource utilization. For systems that focus on some submarine cable spans, a higher traversal frequency can be set for the span of concern, and a lower traversal frequency can be set for the span of non-concern, so that the monitoring requirements of the entire submarine cable system can be met. In actual application, the number of time slices and the traversal frequency can be adjusted according to the frequency range and span range of concern to the submarine cable system. This application does not limit this.

[0112] An embodiment of the present application also provides a submarine cable system, which includes a submarine cable optical fiber, a repeater, a DAS device, and a controller.

[0113] Submarine optical fiber, configured for transmission and sensing of optical signals;

[0114] At least one repeater is provided with at least one loop-back optical path, and the loop-back optical path is provided with an optical switch configured to amplify the optical signal;

[0115] The DAS device is configured to send a detection optical signal and receive and analyze a backscattered optical signal; the backscattered optical signal is an optical signal generated during the forward transmission of the detection optical signal in the optical fiber of the submarine cable;

[0116] A controller configured to obtain monitoring information for monitoring the submarine cable system;

[0117] determining a first target repeater in the submarine cable system according to the monitoring information;

[0118] Controlling a first target optical switch of a first target repeater to be turned on; wherein the first target optical switch is the optical switch of a loopback optical path in the first target repeater;

[0119] Control the DAS equipment to send detection optical signals to the submarine cable optical fiber;

[0120] Controlling the DAS device to receive and analyze the backscattered light signal returned by the first target optical switch;

[0121] The environmental disturbance information of the submarine cable system is determined based on the backscattered light signal.

[0122] In this way, by setting an optical switch in the loopback circuit of the repeater in the DAS device, the controller controls the on and off of the optical switch of the loopback optical path corresponding to the specific area, so that the backscattered signal in the specific area is returned to the DAS device only through the loopback optical path, rather than all areas, thereby improving the sensing response frequency, increasing the frequency range of the submarine cable system to obtain environmental disturbance information, and realizing comprehensive perception of marine events in specific areas.

[0123] In some embodiments, the controller is also used to process the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; extract disturbance characteristics of the time domain signal and / or the frequency domain signal, the disturbance characteristics including at least one of time, amplitude, phase and frequency; and determine the environmental disturbance information of the submarine cable optical fiber based on the disturbance characteristics.

[0124] In some embodiments, the controller is also used to determine the monitored range according to the monitored area information; determine the maximum monitoring range according to the monitored event information and the monitored range; and determine the first target repeater within the monitored range according to the monitored range and the maximum monitoring range.

[0125] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

[0126] It should be noted that those skilled in the art will easily think of other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary technical means in the art that are not disclosed in the present application. The specification and examples are only regarded as exemplary, and the true scope of the present application is indicated by the claims.

[0127] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for monitoring environmental disturbances of a submarine cable system, characterized in that: The method comprises: Acquire monitoring information of the submarine cable system, wherein the monitoring information includes information of the area to be monitored and information of the event to be monitored; Determining the first target repeater in the submarine cable system according to the monitoring information includes: determining a range to be monitored according to the information of the area to be monitored; determining a maximum monitoring range according to the information of the event to be monitored and the range to be monitored; determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range; Controlling a first target optical switch in the first target repeater to be turned on, wherein the first target optical switch is an optical switch of a loopback optical path in the first target repeater; Control the DAS equipment to send detection optical signals to the submarine cable optical fiber; Controlling the DAS device to receive and analyze the backscattered light signal returned by the first target optical switch; the backscattered light signal is an optical signal generated by the detection light signal during the forward transmission of the submarine cable optical fiber; Environmental disturbance information of the submarine cable optical fiber is determined according to the backscattered light signal.

2. The method for monitoring environmental disturbances of a submarine cable system according to claim 1, characterized in that: Determining the environmental disturbance information of the submarine cable optical fiber according to the backscattered light signal includes: Processing the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; Extracting disturbance features of the time domain signal and / or the frequency domain signal, wherein the disturbance features include at least one of time, amplitude, phase and frequency; Environmental disturbance information of the submarine cable optical fiber is determined according to the disturbance characteristics.

3. The method for monitoring environmental disturbances of a submarine cable system according to claim 1, characterized in that: The step of determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range includes: In response to the range to be monitored being less than or equal to the maximum monitoring range, each of the repeaters within the range to be monitored is used as the first target repeater.

4. The method for monitoring environmental disturbances of a submarine cable system according to claim 1, characterized in that: The step of determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range further includes: In response to the range to be monitored being larger than the maximum monitoring range, the range to be monitored is divided according to the maximum monitoring range to obtain N sub-ranges to be monitored; each of the sub-ranges to be monitored is smaller than or equal to the maximum monitoring range, and N is a positive integer greater than or equal to 2; Each of the repeaters in the to-be-monitored range is used as the first target repeater, and each of the repeaters in the to-be-monitored sub-range is used as a target sub-repeater.

5. The method for monitoring environmental disturbances of a submarine cable system according to claim 4, characterized in that: The environmental disturbance monitoring method of the submarine cable system also includes: The following steps are repeated until i=N, where i is a positive integer greater than 0: Controlling the i-th optical switch in the i-th sub-range to be monitored to be turned on at the same time, controlling the DAS device to send the i-th detection optical signal to the submarine cable optical fiber, and controlling the DAS device to receive and analyze the i-th backscattered optical signal passing through each of the i-th optical switches; wherein the i-th optical switch is the optical switch of the loopback optical path of each of the target sub-repeaters in the i-th sub-range to be monitored; After the i-th backscattered light signal passes through all the i-th optical switches, all the i-th optical switches are controlled to be disconnected simultaneously.

6. The method for monitoring environmental disturbances of a submarine cable system according to claim 1, characterized in that: The environmental disturbance monitoring method of the submarine cable system also includes: Set multiple time slices; Dividing the submarine cable optical fiber according to the number of the time slices to obtain a plurality of submarine cable spans, wherein each of the submarine cable spans includes at least one second target repeater, and the number of the time slices is the same as the number of the submarine cable spans; In each of the time slices, controlling the second target optical switches in the submarine cable span corresponding to the time slice to be turned on simultaneously, wherein the second target optical switch is the optical switch of the loopback optical path of the second target repeater in the submarine cable span; Control the DAS device to send the detection optical signal to the submarine cable optical fiber, and control the DAS device to receive and analyze the backscattered optical signal returned by each second target optical switch passing through the submarine cable span; The environmental disturbance information of the submarine cable span is determined according to the backscattered light signal.

7. A submarine cable system, characterized in that: include: Submarine optical fiber, used for transmission and sensing of optical signals; At least one repeater is provided with at least one loop-back optical path, and the loop-back optical path is provided with an optical switch for amplifying an optical signal; DAS equipment, used for sending detection light signal and receiving and analyzing backscattered light signal; the backscattered light signal is the light signal generated by the detection light signal during the forward transmission of the submarine cable optical fiber; A controller, used to obtain monitoring information of the submarine cable system, wherein the monitoring information includes information of the area to be monitored and information of the event to be monitored; Determining the first target repeater in the submarine cable system according to the monitoring information includes: determining a range to be monitored according to the information of the area to be monitored; determining a maximum monitoring range according to the information of the event to be monitored and the range to be monitored; determining the first target repeater within the range to be monitored according to the range to be monitored and the maximum monitoring range; Controlling a first target optical switch of the first target repeater to be turned on; wherein the first target optical switch is the optical switch of the loopback optical path in the first target repeater; Controlling the DAS device to send a detection optical signal to the submarine cable optical fiber; Controlling the DAS device to receive and analyze the backscattered light signal returned by the first target optical switch; Environmental disturbance information of the submarine cable optical fiber is determined according to the backscattered light signal.

8. The submarine cable system according to claim 7, characterized in that: The controller is specifically used for: Processing the backscattered light signal to obtain a time domain signal and / or a frequency domain signal; Extracting disturbance features of the time domain signal and / or the frequency domain signal, wherein the disturbance features include at least one of time, amplitude, phase and frequency; Environmental disturbance information of the submarine cable optical fiber is determined according to the disturbance characteristics.

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