Method and system for detecting spectrum of submarine cable system

Abstract

To provide a method and a system for detecting the spectrum of a submarine cable system.SOLUTION: The method is applied to a submarine cable system including a plurality of end offices, submarine cables, and a plurality of optical repeaters, the method including the steps of: acquiring shipment spectrum test data of the optical repeaters and unique Raman spectrum data of the submarine cables, and acquiring a spectrum base line corresponding to the optical repeaters on the basis of the obtained data; acquiring a gain change model on the basis of the shipment spectrum test data; and acquiring power change data by monitoring and measuring the submarine cable system, and calculating a first gain spectrum on the basis of the power change data, spectrum base line, and gain change model. The spectrum base line includes input and output spectra during normal operation, and the first gain spectrum includes input and output spectra after power change.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present application relates to the field of undersea cable detection technology, and more particularly to a method and system for spectrum detection of undersea cable systems. [Background technology]

[0002] Undersea Fiber Communication Systems are important communication systems that connect various countries and marine equipment through undersea optical fibers, and can span distances from several kilometers to tens of thousands of kilometers. There is a certain power penalty in the transmission of optical signals through the medium, and if the transmission distance is too long, the attenuation of the optical signal in the undersea cable becomes serious, so it is necessary to amplify the optical signal by installing optical repeater amplifiers (RPTs) in the undersea cables at regular intervals.

[0003] A typical optical repeater amplifier is a rare-earth doped optical fiber amplifier such as an erbium-doped optical fiber amplifier (EDFA). In use, the EDFA amplifies and outputs an optical signal input by a pump light source, thereby maintaining the transmission stability of the optical signal in the submarine cable system. During the operation of the submarine cable system, factors such as pump failure, temperature change, and increased optical fiber loss in the cable change the input spectrum and / or output spectrum of the EDFA, affecting the transmission stability of the submarine cable system.

[0004] During the operation of a submarine cable system, the transmission status of the submarine cable system can be obtained by detecting the spectral change of the EDFA. However, when an EDFA is installed in a submarine cable system, it is installed underwater together with the submarine optical fiber, so that when a fault occurs in the submarine cable system, it is not possible to directly detect the spectral change in the submarine optical fiber. In an indirect manner, for example, a tunable coherent optical time domain reflectometer (COTDR) transmits detection light to the submarine cable, so that the spectral change of the optical repeater in the submarine cable system can be obtained. In this case, however, only a relative change of the spectrum can be obtained, and the accuracy is low. In addition, this method requires occupying multiple business wavelength channels to obtain the spectrum, so that when there are relatively many business signals in the submarine cable, there are few wavelengths available for measuring the spectrum, which affects the accuracy of the spectrum detection, and even the spectrum detection cannot be performed when the service is fully configured. Therefore, in order to meet the operational stability requirements of the submarine cable system, there is an urgent need for a spectrum detection method that improves the accuracy of detecting the spectral performance change of each optical repeater in the submarine cable system. Summary of the Invention [Problem to be solved by the invention]

[0005] The present application provides a method and system for spectrum detection in a submarine cable system to solve the problem of low accuracy in acquiring the spectrum variation of each optical repeater in the submarine cable system. [Means for solving the problem]

[0006] A spectrum detection method for a submarine cable system according to a first aspect of an embodiment of the present invention includes a plurality of terminal stations configured to transmit and receive optical signals, a submarine cable installed between the plurality of terminal stations to connect the plurality of terminal stations, and a plurality of optical repeaters installed on the submarine cable, respectively, to amplify optical signals transmitted from the terminal stations, the method comprising: the step of acquiring first spectral test data for a plurality of optical repeaters and second spectral test data for the submarine cables, the first spectral test data including shipment spectral test data for each optical repeater and the second spectral test data including characteristic Raman spectral data for the submarine cables; acquiring a spectral baseline corresponding to each optical repeater based on each of the first spectral test data and the second spectral test data, the spectral baseline including an input spectrum and an output spectrum of each optical repeater after an optical signal of a preset power is input to the submarine cable system; acquiring a gain change model corresponding to each optical repeater based on each of the first spectral test data, the gain change model including gain data of the optical repeater for optical signals of different wavelengths and / or different powers; monitoring and measuring the submarine cable system to acquire power change data; and calculating a first gain spectrum based on the power change data, the spectral baseline and the gain change model, the first gain spectrum including an input spectrum and an output spectrum of each optical repeater after a power change of the optical signal in the submarine cable system.

[0007] The method includes obtaining first spectrum test data of each optical repeater in the submarine cable system and second spectrum test data of the submarine cable, calculating and obtaining a spectrum baseline corresponding to each optical repeater based on the first spectrum test data and the second spectrum test data, then obtaining gain data of each optical repeater receiving different wavelengths and different powers based on the first spectrum test data, obtaining a gain change model corresponding to each optical repeater, and upon detecting that a power change has occurred in the submarine cable system, calculating the input and output spectra of each optical repeater after the power change based on the power change data, the spectrum baseline and the gain change model to obtain a first gain spectrum. Through the above steps, the input and output spectra of each optical repeater affected by a power change are calculated and obtained after the power change has occurred in the submarine cable system, thereby obtaining the gain spectrum of each optical repeater in the submarine cable system, and improving the accuracy of spectrum acquisition.

[0008] In one possible embodiment, the step of obtaining a spectral baseline corresponding to each optical repeater based on each of the first and second spectral test data includes the steps of obtaining power information corresponding to a wavelength range and different wavelength signals of an input optical signal of the submarine cable system, obtaining a loss spectrum for the input optical signal of the submarine cable and a gain spectrum for the input optical signal of each optical repeater based on the wavelength range and the power information, and determining the loss spectrum and gain spectrum corresponding to the input optical signal as a spectral baseline. In this way, when the submarine cable system is operating normally, the spectral baseline of the optical signal in the submarine cable system is obtained by obtaining the gain data for the optical signal of each optical repeater and the loss data for the optical signal of the submarine cable, so that the spectral data during the normal operation of the submarine cable system can be determined, and when a fault occurs in the submarine cable system that affects the spectral data, the spectral data can be quickly updated based on the spectral baseline, improving the efficiency of spectrum calculation.

[0009] In one possible embodiment, the step of obtaining a gain change model corresponding to each optical repeater based on each first spectrum test data includes the steps of obtaining gain data for optical signals of different wavelengths and / or different powers for each optical repeater based on the first spectrum test data, and determining a gain change model corresponding to each optical repeater based on the gain data corresponding to each optical repeater. By determining the gain change model, after a fault occurs in the submarine cable system affecting the transmission of the optical signal, input and output spectra corresponding to each optical repeater can be calculated and obtained based on the changed power data, thereby improving the accuracy of spectrum acquisition.

[0010] In one possible embodiment, the step of monitoring and measuring the submarine cable system to obtain power change data includes the steps of: transmitting a first detection light of a single wavelength to the submarine cable system; and obtaining a second gain spectrum of the first detection light in the submarine cable system as power change data, the second gain spectrum including an input spectrum and an output spectrum of the first detection light passing through each optical repeater; and the step of calculating the first gain spectrum based on the power change data, the spectral baseline and the gain change model includes the steps of: if the second gain spectrum does not match the spectral baseline, obtaining a gain difference between the second gain spectrum and the spectral baseline; and calculating the first gain spectrum based on the gain difference and the gain change model. In this way, the calculation of the first gain spectrum can be performed by transmitting the detection light of a single wavelength to the submarine cable system, and the number of business channels occupied when monitoring and measuring power changes in the submarine cable system can be reduced, thereby reducing the impact on the transmission efficiency of the submarine cable system when performing spectrum detection.

[0011] In one possible embodiment, if the second gain spectrum does not match the spectral baseline, the step of obtaining a gain difference between the second gain spectrum and the spectral baseline includes the steps of: extracting gain spectrum information from the spectral baseline, the gain spectrum information including an input spectrum and an output spectrum of an optical signal corresponding to the first detection optical wavelength in the spectral baseline that has passed through each optical repeater; and comparing the second gain spectrum with the gain spectrum information to obtain a gain difference. According to the correspondence between each optical repeater and the spectral baseline and the second gain spectrum, the gain difference of each optical repeater can be calculated to obtain the spectral change data of the submarine cable system, and the accuracy of the spectrum acquisition can be improved.

[0012] In one possible embodiment, the second gain spectrum includes a second input spectrum and a second output spectrum, the gain spectrum information includes an input gain spectrum and an output gain spectrum, and the gain difference includes an input gain difference and an output gain difference, and the step of comparing the second gain spectrum and the gain spectrum information to obtain the gain difference includes the steps of: calculating the difference between the second input spectrum and the input gain spectrum corresponding to each optical repeater to obtain the input gain difference, calculating the difference between the second output spectrum and the output gain spectrum corresponding to each optical repeater to obtain the output gain difference, and arranging the input gain difference and the output gain difference corresponding to each optical repeater according to the transmission and reception order of each optical repeater to obtain the gain difference. By obtaining and arranging the input gain difference and the output gain difference, the input spectrum and the output spectrum of each optical repeater can be calculated according to a gain change model, and the spectrum acquisition efficiency can be improved.

[0013] In one possible embodiment, after the step of comparing the second gain spectrum with the gain spectrum information to obtain the gain difference, the method further includes the steps of: detecting each input gain difference and output gain difference in the gain difference to obtain first difference data that is greater than a first preset value or smaller than a preset value; if the first difference data is an input gain difference, determining that the fault area of ​​the submarine cable system is the submarine cable connected to the input end of the first optical repeater corresponding to the first difference data; and if the first difference data is an output gain difference, determining that the fault area of ​​the submarine cable system is the first optical repeater. The type of the first gain difference allows the location of the area where the fault occurs in the submarine cable system to be determined, which makes it easy to investigate the fault and perform maintenance.

[0014] In one possible embodiment, the step of calculating the first gain spectrum based on the gain difference and the gain variation model comprises: The method includes the steps of: determining a second optical repeater in the submarine cable system based on a position of the first optical repeater, the second optical repeater including each optical repeater connected to an output end of the first optical repeater via the submarine cable; and calculating an input spectrum and an output spectrum of each second optical repeater based on a gain difference and a gain change model corresponding to the second optical repeater to obtain a first gain spectrum. After obtaining the fault location of the submarine cable system, the input and output spectra of each optical repeater subsequently connected to the fault location are calculated to obtain the spectrum change of the submarine cable system, thereby reducing the number of calculations and improving the spectrum acquisition efficiency.

[0015] In one possible embodiment, the method further includes a step of displaying the first gain spectrum after the step of calculating the first gain spectrum. By displaying the spectrum change in this manner, information such as the location of the fault and the cause of the fault can be presented to the maintenance staff, making it easier to maintain the submarine cable system.

[0016] A spectrum detection system for a submarine cable system according to a second aspect of the present invention is installed in a submarine cable system including a plurality of terminal stations configured to transmit and receive optical signals, a submarine cable installed between the plurality of terminal stations to connect the plurality of terminal stations, and a plurality of optical repeaters each installed in the submarine cable system to amplify an optical signal transmitted from the terminal station, and is used to perform any of the above-mentioned spectrum detection methods for a submarine cable system, the spectrum detection system including a network management device installed in one terminal station and connected to another terminal station, and a submarine cable monitoring and measurement device connected to the submarine cable and the network management device, The network management device includes a data collection unit configured to acquire first spectral test data of a plurality of optical repeaters and second spectral test data of the submarine cable, and a processing and calculation unit configured to acquire a spectral baseline corresponding to each optical repeater based on each of the first spectral test data and the second spectral test data, and to acquire a gain change model corresponding to each optical repeater based on each of the first spectral test data, and the submarine cable monitoring and measurement device is configured to monitor and measure the submarine cable system to acquire power change data, and the processing and calculation unit is further configured to calculate a first gain spectrum based on the power change data, the spectral baseline and the gain change model.

[0017] A network management device and a submarine cable monitoring and measurement device are respectively installed in the submarine cable system, the submarine cable monitoring and measurement device can monitor and measure the submarine cable system to obtain power change data of the submarine cable system, the network management device obtains and processes the first spectrum test data and the second spectrum test data to obtain a spectrum baseline of the submarine cable system and a gain change model corresponding to an optical repeater, so as to calculate a gain spectrum corresponding to each optical repeater after a power change occurs in the submarine cable system, and to improve the accuracy of the obtained gain spectrum.

[0018] In one possible embodiment, the network management device further includes a spectrum display unit configured to display the first gain spectrum. By installing the spectrum display unit in the network management device, after the first gain spectrum is calculated and obtained, the first gain spectrum can be displayed, thereby reminding the maintenance staff to maintain the submarine cable system. Effect of the Invention

[0019] As can be seen from the above technical configuration, the present application provides a spectrum detection method and system for a submarine cable system, which is applied to a submarine cable system including a plurality of terminals, a submarine cable and a plurality of optical repeaters, the method comprising the steps of: obtaining first spectrum test data and second spectrum test data, and obtaining a spectrum baseline corresponding to each optical repeater based on the obtained data; obtaining a gain change model corresponding to each optical repeater based on each of the first spectrum test data; obtaining power change data by monitoring and measuring the submarine cable system, and calculating a first gain spectrum based on the power change data, the spectrum baseline and the gain change model, wherein the first spectrum test data includes shipment spectrum test data of each optical repeater, the second spectrum test data includes inherent Raman spectrum data of the submarine cable, the spectrum baseline includes an input spectrum and an output spectrum during normal operation of the submarine cable system, the gain change model includes gain data of the optical repeater for optical signals of different wavelengths and / or different powers, and the first gain spectrum includes an input spectrum and an output spectrum of each optical repeater after a power change of the optical signal in the submarine cable system. With this method, when an abnormality occurs in the transmission power in a submarine cable system, the spectrum after the change in each optical repeater is calculated using a gain change model, and the input spectrum and output spectrum corresponding to each optical repeater are obtained, thereby improving the accuracy of spectrum acquisition. [Brief description of the drawings]

[0020] Hereinafter, in order to more clearly explain the technical configuration of the present application, drawings that need to be used in the embodiments are briefly introduced, and those skilled in the art can derive other drawings based on these drawings without any creative efforts. [Figure 1] FIG. 2 is a schematic diagram of the measurement wavelength of a COTDR. [Diagram 2] 1 is a schematic flow diagram of a spectrum sensing method for a submarine cable system in an embodiment of the present application; [Figure 3a] FIG. 2 is a schematic diagram showing a loss spectrum of a single-stage submarine cable in an embodiment of the present application. [Figure 3b] FIG. 13 is a schematic diagram of a loss spectrum of another single-stage submarine cable in an embodiment of the present application. [Figure 3c] FIG. 2 is a schematic diagram of a gain spectrum by an optical repeater in an embodiment of the present application. [Figure 3d] 3 is a schematic diagram of a gain spectrum and a loss spectrum of an optical repeater and an undersea cable in an embodiment of the present application. [Figure 4] FIG. 2 is a schematic flow diagram of obtaining a spectral baseline in an embodiment of the present application. [Diagram 5] 1 is a schematic diagram of the structure of an optical repeater according to an embodiment of the present application. [Figure 6] FIG. 2 is a schematic flow diagram for obtaining a gain variation model in an embodiment of the present application. [Figure 7a] FIG. 13 is a schematic diagram of a fault in the gain change model in an embodiment of the present application. [Figure 7b] FIG. 13 is a schematic diagram of another fault in the gain change model in an embodiment of the present application. [Figure 7c] FIG. 13 is a schematic diagram of yet another fault in the gain change model in an embodiment of the present application. [Figure 7d] FIG. 13 is a schematic diagram of yet another fault in the gain change model in an embodiment of the present application. [Figure 7e] FIG. 13 is a schematic diagram of yet another fault in the gain change model in an embodiment of the present application. [Figure 8]FIG. 2 is a flow diagram of a method for monitoring and measuring a submarine cable system in an embodiment of the present application; [Figure 9] FIG. 1 is a flow diagram of obtaining gain difference in an embodiment of the present application. [Figure 10] FIG. 4 is a schematic diagram of a second gain spectrum after a loss fault occurs in the submarine cable system in an embodiment of the present application. [Figure 11] FIG. 4 is a schematic diagram of a second gain spectrum after pump loss occurs in the submarine cable system in an embodiment of the present application. [Figure 12] 1 is a structural schematic diagram of a submarine cable system in an embodiment of the present application; [Figure 13] 1 is a structural schematic diagram of a spectrum detection system for a submarine cable system in an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The following describes the embodiments in detail, examples of which are shown in the drawings. When referring to the drawings in the following description, the same reference numerals refer to the same or similar elements in the various drawings unless otherwise stated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. They are merely examples of devices and methods consistent with some aspects of the present application, as detailed in the claims.

[0022] In the embodiments of the present application, a submarine cable system, that is, a submarine optical fiber system, is a communication network system composed of a plurality of communication cables. The communication cables in the system are laid on the ocean floor and can be called submarine cable lines. The submarine cable lines transmit optical communication signals between terminal stations and can realize communication functions across ocean areas. The submarine cable system can realize long-distance communication, for example, data communication across 10,000 kilometers of ocean. The submarine cable system described in the embodiments of the present application can also be used in short-distance communication areas such as across rivers and lakes.

[0023] With the rapid technological development and innovation in the field of communications, in order to apply the latest terminal transmission equipment to the submarine cable system, the construction of the submarine cable system adopts the open cable architecture (i.e., open submarine cable network). In the open cable architecture, the terminal equipment is decoupled from the underwater equipment, so that the terminal transmission equipment of different manufacturers can be replaced without replacing the underwater equipment in the submarine cable system, thereby reducing the renewal cost of the submarine cable system and improving the flexibility of the submarine cable system. Moreover, with the development of the open cable architecture, monitoring and controlling the transmission performance of the entire submarine cable system and obtaining the input and output spectra of the submarine cable system become important means for detecting the operation of the submarine cable system.

[0024] In some embodiments, the submarine cable system includes terminal equipment located on the water surface, and submarine cables and underwater equipment located underwater, where the terminal equipment is used to transmit and receive optical signals, the submarine cables are used to transmit optical signals, and the underwater equipment is used to realize functions such as gain of the optical signals, branching of the submarine cables, etc. Since the optical signals transmitted from the terminal equipment have a certain attenuation during transmission through the medium, and there is a certain insertion loss when the submarine cables are connected to the underwater equipment, the underwater equipment includes an optical repeater for amplifying the optical signals, thereby reducing the power loss of the optical signals caused by the submarine cables and the underwater equipment during long-distance transmission.

[0025] In order to carry more data, the optical signal transmitted from the terminal equipment is a composite signal of multiple wavelength signals within one wavelength band. Take the C wavelength band commonly used in undersea cable systems as an example, whose wavelength range is distributed between 1530 nm and 1568 nm and can be subdivided into multiple wavelengths λ1 to λn, and is used to refer to any wavelength within the C wavelength band.

[0026] Therefore, in some embodiments, the input and output spectrum states of the submarine cable system can be detected by tunable COTDR spectrum scanning. Among them, COTDR is a coherent optical time domain reflectometer, and specifically, the COTDR can measure the input spectrum and the output spectrum of the optical repeater in the submarine cable system by transmitting a tunable detection optical signal to the submarine cable system during operation and receiving a return optical signal of the detection optical signal. As shown in Fig. 1, the wavelengths of the business data transmitted in the submarine cable system are λ1 to λn, and the COTDR can obtain the spectrum data of the submarine cable system of the optical signals with wavelengths of λ3, λ5, and λ7 by transmitting the optical signals with wavelengths of λ3, λ5, and λ7, respectively, and receiving the return optical signals of the optical signals with three different wavelengths. Since the COTDR can only obtain the spectral data of the transmitted detection optical signal, the higher the wave number of the detection optical signal transmitted from the COTDR, the clearer the spectrum obtained. However, since the detection optical signal needs to occupy the channel of the business optical signal transmission, the business carrying capacity of the submarine cable system is reduced when the wave number of the detection optical signal is high. When the business is fully configured in the submarine cable system, it becomes impossible to transmit the detection optical signal to the submarine cable system to obtain the spectral information. The spectrum obtained by measuring with the COTDR is merely the relative change situation of one or more wavelength band spectra, and cannot reflect the input and output spectral data of each optical repeater.

[0027] In addition, the spectrum information in the submarine cable system shows that each wavelength arranged according to wavelength order is a serial corresponding to the magnitude of optical power, and includes two dimensions: the magnitude of power and the magnitude of gradient. Since the product of the wavelength and frequency of the optical signal is the speed of light, when the optical signal of each wavelength has one corresponding optical power and is in the same medium, the higher the frequency of the optical signal, the shorter the wavelength, so the spectrum information can also show that each wavelength arranged according to frequency order is a serial corresponding to the magnitude of optical power. Regarding the input spectrum and output spectrum of the underwater equipment in the submarine cable system, subtracting the input spectrum from the output spectrum results in a gain spectrum corresponding to the underwater equipment, and when the underwater equipment has the function of signal amplification, the gain spectrum is a positive gain, and when the underwater equipment has the function of signal attenuation, the gain spectrum is a negative gain.

[0028] The gain value for the power of an optical repeater is obtained by calculating the power ratio between the output power and the input power, and then multiplying it by 10 to calculate the logarithm of the power ratio to the base 10, and the unit is dB. The gain value can be a positive or negative value, with a positive value representing a gain and a negative value representing a loss. For example, when the power ratio is 1, i.e., when the input power and the output power are the same, the signal has no gain or loss, and the gain is 0 dB; when the power ratio is 2, the gain is about 3 dB; and when the power ratio is 1 / 2, the gain is about -3 dB. Furthermore, when the power ratio is 2, n When n is an integer, a power gain value of 3ndB is obtained.

[0029] The spectrum detection method for a submarine cable system according to the present application is applied to a submarine cable system. In an embodiment of the present application, the submarine cable system includes a plurality of terminal stations, a submarine cable, and a plurality of optical repeaters, among which the plurality of terminal stations are configured to transmit and receive optical signals, the submarine cables are installed between the plurality of terminal stations to connect the plurality of terminal stations, and the plurality of optical repeaters are respectively installed in the submarine cables to amplify the optical signals transmitted from the terminal stations.

[0030] In addition, since the optical repeater in the submarine cable system has an upper limit on the gain for the optical signal, when the submarine cable in the submarine cable system is long, the optical signal can be amplified by installing multiple optical repeaters in the submarine cable so that the power of the optical signal transmitted through the submarine cable is not too low. In order to unify the gain power of different optical repeaters, in some embodiments, the length of the submarine cable between two adjacent optical repeaters is made the same, and for example, one optical repeater is installed every 100 km in the submarine cable to perform optical signal gain, of which the interval of 100 km is merely an illustrative explanation, and the installation interval of the optical repeaters is related to the loss of the optical signal in the submarine cable and the gain power of the optical repeater itself.

[0031] When applied to the above submarine cable system, as shown in FIG. 2, the method includes the following steps S210 to S250.

[0032] In step S210, first spectrum test data of the multiple optical repeaters and second spectrum test data of the submarine cable are obtained.

[0033] The first spectrum test data includes the shipment spectrum test data of each optical repeater, and the second spectrum test data includes the inherent Raman spectrum data of the submarine cable. The shipment spectrum test data of the optical repeater includes the gain information of the optical repeater for optical signals of different wavelengths and different powers. Specifically, the shipment spectrum test data of the optical repeater is obtained by testing the gain effect of the optical repeater for optical signals of different wavelengths and different powers at the shipment stage, thereby obtaining the shipment spectrum test data. The inherent Raman spectrum data of the submarine cable is divided into an inherent loss spectrum and a Raman loss spectrum, which are obtained by calculating the absorption spectrum and scattering spectrum of the submarine cable respectively, among which the loss can also be called negative gain.

[0034] As can be seen from the transmission characteristics of optical signals, when the optical signals transmitted through the same medium have the same propagation distance and initial power, the power loss of the optical signal with a long wavelength (i.e., low frequency) is small, and the power loss of the optical signal with a short wavelength (i.e., high frequency) is large. Therefore, as shown in Figure 3a, the loss of the optical signal of the optical fiber submarine cable in the submarine cable system is also small for the optical signal with a long wavelength, and large for the optical signal with a short wavelength, and the inherent Raman spectrum of the submarine cable exhibits a negative slope, and when the submarine cable receives signals with the same optical power between different wavelengths, the output spectrum of the submarine cable exhibits a positive slope, and the optical power corresponding to each wavelength is significantly reduced compared to the input optical signal.

[0035] In addition, the loss of the optical signal of the submarine cable is also related to the length of the submarine cable, and the longer the length of the submarine cable, the greater the loss of the optical signal of the submarine cable, and the loss of the optical signal of the submarine cable with different lengths is also different. In some embodiments of the present application, the length of the submarine cable between each optical repeater is the same, that is, the submarine cable system is a standard span, and when the submarine cable system is operating normally, the loss of the optical signal of each stage of the submarine cable is made to be consistent, so that the input spectrum of each optical repeater is made consistent, and the problem of the gain effect of the optical repeater being different due to the difference in input optical power is reduced. In some other embodiments, during the installation of the submarine cable system, the optical repeaters with different powers are matched or the power of the optical repeaters is adjusted to make the output spectrum of each optical repeater the same, so that when the lengths of the submarine cable between any two adjacent optical repeaters in the submarine cable system are different, the loss change of the submarine cable due to the power change is reduced.

[0036] Therefore, in order to make the optical powers of different wavelengths of the optical signal output from the submarine cable system the same, the optical powers of different wavelengths in the input optical signal can be adjusted so that the input spectrum has a negative slope, as shown in Figure 3b, so that an output spectrum without slope can be output after the loss caused by the submarine cable. Note that the negative slope of the input spectrum corresponds to the loss to the optical signal in the submarine cable.

[0037] The optical repeater in the submarine cable system amplifies the optical signal, thereby reducing the effect of loss on the optical signal of the submarine cable. As can be seen from FIG. 3b, the optical signal with a negative slope becomes an output spectrum without slope due to loss after passing through a certain length of the submarine cable, and at this time, the optical signal can be amplified by the optical repeater to improve the transmission performance of the submarine cable system. As shown in FIG. 3c, the optical repeater amplifies the output spectrum without slope output from the submarine cable to obtain an output spectrum with a negative slope again, and the submarine cable connected to the optical repeater can receive the output spectrum with a negative slope and perform the process of FIG. 3b again. Therefore, in some embodiments of the present application, when the submarine cable system is operating normally, the loss and gain processes shown in FIG. 3b and FIG. 3c are alternated, and the number of alternations is the same as the number of optical repeaters. Note that in the embodiments of the present application, the output spectrum of the submarine cable connected to the input end of the optical repeater becomes the input spectrum of the optical repeater, and the output spectrum of the optical repeater becomes the input spectrum of the submarine cable connected to the output end of the optical repeater.

[0038] In step S220, a spectral baseline corresponding to each optical repeater is obtained based on each of the first and second spectral test data.

[0039] Wherein, the spectral baseline includes the input spectrum and output spectrum of each optical repeater after the submarine cable system inputs an optical signal of a preset power, the preset power being the power of the optical signal input to the submarine cable during normal operation of the submarine cable system. Since the output spectrum of an optical repeater is the input spectrum of the submarine cable connected to the output end of the optical repeater, and the input spectrum of an optical repeater is the output spectrum of the submarine cable connected to the input end of the optical repeater, the spectral baseline is also the input spectrum and output spectrum of the submarine cable at each stage after the submarine cable system inputs an optical signal of a preset power.

[0040] In some embodiments of the present application, after obtaining the first spectrum test data corresponding to the optical repeater and the second spectrum test data corresponding to the submarine cable, the output spectrum of each stage of the submarine cable and the output spectrum of each optical repeater can be calculated based on the power of the optical signal input to the submarine cable system and the length of the submarine cable of each stage to obtain a spectrum baseline. For example, as shown in Fig. 3d, during normal operation of the submarine cable system, the input spectrum of the optical signal is calculated in sequence according to the signal transmission order, so that the output spectrum after the loss in the submarine cable and the output spectrum after the gain in the optical repeater can be calculated to obtain a spectrum baseline.

[0041] Exemplarily, in some embodiments, as shown in FIG. 4, step S220 of obtaining a spectral baseline may include the following steps S221 to S223.

[0042] In step S221, the wavelength range of the input optical signal of the submarine cable system and the power information corresponding to the different wavelength signals are obtained.

[0043] First, it is necessary to obtain all wavelengths of signals contained in the input optical signal of the submarine cable system and power information corresponding to different wavelengths. Since the loss of the optical signal in the submarine cable affects the wavelength of the optical signal, the power of the optical signals with short wavelengths in the input optical signal is high and the power of the optical signals with long wavelengths is low.

[0044] In addition, the information of the input optical signal can be obtained directly from the equipment that emits the optical signal. In the embodiment of the present application, when an optical signal is transmitted by a terminal equipment in a submarine cable system, the spectrum of the transmitted optical signal is stored for convenience of subsequent retrieval.

[0045] In step S222, a loss spectrum for the input optical signal to the submarine cable and a gain spectrum for the input optical signal to each optical repeater are obtained based on the wavelength range and power information.

[0046] After obtaining the wavelength range and power information of the input optical signal, a loss spectrum for the input optical signal of the submarine cable can be obtained based on the loss conditions for different wavelength signals of the submarine cable in the second spectrum test data, and then an output spectrum of one stage of the submarine cable can be obtained based on the loss spectrum and the input spectrum. Also, a gain spectrum for the input optical signal of the optical repeater can be obtained based on the gain conditions for the optical signal of the optical repeater in the first spectrum test data, thereby amplifying the power of the input optical signal after the loss caused by the submarine cable.

[0047] As shown in Figure 3d, the optical signal is m-1 In this example, RPT stands for optical repeater, and m is a positive integer greater than 1. After the optical signal is lost through one stage of undersea cable, it will have a spectrum with a slope of 0. m-1 Output to RPT m-1 amplifies the optical signal, and the gain spectrum is m-1 and RPT m The loss spectrum of the undersea cable between the RPT mThe spectral tilt of the optical signal transmitted to the

[0048] In step S223, the loss spectrum and gain spectrum corresponding to the input optical signal are determined as a spectral baseline.

[0049] The gain spectrum corresponding to each optical repeater and the loss spectrum corresponding to each stage of the submarine cable can be determined as the spectral baseline of the submarine cable system according to the connection order of the submarine cables and the optical repeaters.

[0050] In some embodiments, the spectral baseline may further include the input and output spectra of each optical repeater and the input and output spectra of each stage of the submarine cable after substituting the input spectrum of the optical signal into the gain spectrum and the loss spectrum, where the power and slope of the optical signal in the spectral baseline are the nominal power and nominal slope of the submarine cable system, respectively.

[0051] According to the solution in the above embodiment, while the submarine cable system is operating normally, gain data for the optical signal of each optical repeater and loss data for the optical signal of the submarine cable can be obtained, and the spectral baseline of the optical signal in the submarine cable system can be obtained, so that the spectral data during the normal operation of the submarine cable system can be determined. When a fault occurs in the submarine cable system that affects the spectral data, the spectral data can be quickly updated based on the spectral baseline, thereby improving the efficiency of spectrum calculation.

[0052] In step S230, a gain variation model corresponding to each optical repeater is obtained based on each first spectrum test data.

[0053] Wherein, the gain change model includes gain data of the optical repeater for optical signals of different wavelengths and / or different powers. In an embodiment of the present application, the optical repeater applied to the submarine cable system is an EDFA, and as shown in Figure 5, the EDFA includes at least a pump light source, an optical coupler, an optical isolator, an erbium-doped optical fiber, and an optical filter. In use, the EDFA emits pump light from the pump light source to excite erbium particles in the erbium-doped optical fiber to a high level, and when the input optical signal passes through the erbium-doped optical fiber, the high-level particles return from the excited state to the ground state, thereby amplifying the input optical signal and generating gain.

[0054] In some embodiments, as shown in FIG. 6, step S230 of obtaining a gain variation model may include the following steps S231 to S232.

[0055] In step S231, gain data for optical signals of different wavelengths and / or different powers is obtained for each optical repeater based on the first spectrum test data.

[0056] Since the first spectrum test data includes gain data of the optical repeater for optical signals of different wavelengths and / or different powers, the gain data corresponding to each optical repeater can be directly obtained by the first spectrum test data. Note that, since the gain data of the optical signal of the EDFA is related to the input spectrum, each optical signal power in the input spectrum has a corresponding gain data.

[0057] In step S232, a gain change model corresponding to each optical repeater is determined based on the gain data corresponding to each optical repeater.

[0058] After obtaining gain data for optical signals of different wavelengths and / or different powers for each optical repeater, a gain change model is determined by statistically comparing the gain data when the power of optical signals of different wavelengths is different. As a result, when loss in the submarine cable system increases or other abnormalities occur in the optical signal power, the gain data after the change can be calculated and obtained using the gain change model.

[0059] Since the gain data of the optical signal of the EDFA is related to the optical signal power, the change of the input spectrum input to the EDFA and the occurrence of a fault in the EDFA itself are the source of gain abnormality in the submarine cable system, and these faults also cause the gain spectrum of the EDFA to change. Therefore, in some embodiments, the gain change model can further include a change coefficient in the submarine cable system, and this change coefficient is the gain influence coefficient for the EDFA caused by the fault in the submarine cable system. For example, when the submarine cable system is operating normally, the power value in the input spectrum and the output spectrum during the operation of each EDFA can be the nominal power, and the slope of the spectrum can be the nominal slope. When a fault occurs in the submarine cable system, the influence on the gain spectrum of the EDFA of the submarine cable system includes the influence on the power value and the slope of the spectrum, so there are several situations in determining the change coefficient:

[0060] First, a change occurs in the nominal power of the input spectrum of one EDFA in the undersea cable system, and the EDFA in the undersea cable system operates in power-locked mode, so that the gain of the EDFA for the optical signal after the power change is greater than the gain for the optical signal of the nominal power, and there is a difference in the gain for the optical signals of different wavelengths, and the slope of the output spectrum of the EDFA obtained is different from the nominal slope, as shown in Figure 7a. Specifically, when the input spectrum of the EDFA is not the nominal power, the slope of the output spectrum of the EDFA changes with the change of the EDFA input spectrum, and the change coefficient is represented by Δk1.

[0061] Next, as shown in Figure 7b, the input power of the EDFA in the undersea cable system does not change, but the slope of the input spectrum changes. In this case, the slope of the output spectrum also changes with the change in the slope of the input spectrum, and the slope change coefficient is shown as Δk2.

[0062] As shown in FIG. 7c, in some embodiments, a change occurs when both the power magnitude and the slope of the input spectrum of the EDFA change, and the change in the output spectrum needs to simultaneously consider both the change in the power and the change in the slope of the input spectrum, and the change coefficient is the superposition of the two, which is denoted by (Δk1+Δk2).

[0063] In some embodiments of the present application, the input spectrum does not change, but the gain of the EDFA to the optical signal may change due to pump loss in the EDFA. As shown in Figure 7d, the input spectrum has a nominal power and a nominal slope, and the gain effect of the EDFA to the optical signal is affected by the number of pump light sources that are lost, and the impact of pump loss is related to the total number of pump light sources and the number of pump loss in one EDFA. At this time, the power and slope of the output spectrum both change, and the impact coefficient on the power is ΔP EDFA and the effect on the slope can be denoted as Δk3. EDFA can be calculated directly according to the total number of pump light sources and the number of pump failures. Take the EDFA as an example, where two pump light sources pump1 and pump2 are installed. When pump2 is disabled and pump1 works normally, the gain effect of the EDFA is close to 1 / 2 of the original, so that the power of the output spectrum is reduced by about 3 dB.

[0064] In addition, the loss spectrum of the optical fiber connected to the output end of the repeater changes due to the change in the output power of the repeater, and the Raman effect in the optical fiber causes the spectrum slope to differ under different incident optical powers. For example, as shown in Figure 7e, the higher the incident optical power, the more significant the power transition between different wavelengths becomes, and the larger the slope change becomes, and the change coefficient is denoted as Δk4.

[0065] Therefore, in the gain variation model, the spectral power variation in a submarine cable system can be described by the following equation (1):

[0066]

number

[0067] where P is the spectral power data in the undersea cable, and P base is the nominal power of the input optical signal in the submarine cable system, and ΔP EDFA is the effect on the output spectral power of the EDFA when the pump is turned off, and ΔP Loss is the loss relative to the nominal power of the input optical signal in the undersea cable.

[0068] The spectral tilt change in a submarine cable system can be described by the following equation (2):

[0069]

number

[0070] where k is the spectral slope data for the undersea cable, and k base is the nominal slope of the input optical signal in the undersea cable system.

[0071] Since the input spectrum and output spectrum of each EDFA must be accounted for in two dimensions, power and slope, the input spectrum or output spectrum of an EDFA can be expressed by the following Equation (3).

[0072]

number

[0073] In addition, in some embodiments, the formula (4) is applied not only to the situation of the communication bands λ1 to λn applied to the entire submarine cable system, but also to the situation of the smaller bands λi to λj among them, and the formula (4) can be expressed as follows:

[0074]

number

[0075] Here, i and j are both positive integers greater than or equal to 1 and less than or equal to n, and i is greater than j.

[0076] In the above embodiment, a gain change model corresponding to an optical repeater can be determined based on the fault information in the submarine cable system and the gain data for different power signals of the optical repeater. After a fault affecting optical signal power occurs in the submarine cable system, the input spectrum and output spectrum corresponding to each optical repeater can be calculated and obtained based on the fault and the changed power data, thereby improving the accuracy of spectrum acquisition.

[0077] In step S240, the submarine cable system is monitored and measured to obtain power variation data.

[0078] The monitoring and measuring of the submarine cable system can be realized by installing a monitoring and measuring device in the terminal equipment of the submarine cable system. In the embodiment of the present application, the monitoring and measuring function of the submarine cable system can be realized by installing a COTDR so as to be connected to the terminal equipment, and for example, as shown in Fig. 8, step S240 of monitoring and measuring the submarine cable system to obtain power variation data can include the following steps S241 to S242.

[0079] In step S241, a first detection light of a single wavelength is transmitted to the undersea cable system.

[0080] While the submarine cable system is operating normally, the operating state of the submarine cable system can be detected by a method in which a COTDR connected to a terminal device transmits a first detection light to the submarine cable system. In some embodiments of the present application, the wavelength of the first detection light is any of the wavelengths (e.g., λ2 or λ4) in the communication bands λ1 to λn used in the submarine cable system, and the first detection light needs to be transmitted by occupying one wavelength of a repeater, so that the first detection light is carried by an available wavelength in the submarine cable system during monitoring and measurement, thereby realizing the purpose of transmitting the first detection light to the submarine cable system.

[0081] In addition, the shorter the wavelength, the greater the effect of the gain on the optical signal, and the longer the wavelength, the smaller the effect of the gain on the optical signal. Therefore, when the first detection light is an optical signal with a short or long wavelength, the change in the spectrum of the submarine cable system will cause a large change in the gain spectrum. In some embodiments, when the C wavelength band is the operating wavelength band in the submarine cable system, the wavelength range of the first detection light can be selected from 1530 nm to 1535 nm and 1560 nm to 1568 nm. The above wavelength range of the first detection light is only one possible embodiment, and the specific wavelength of the first detection light also needs to be determined based on the operating wavelength occupied in the submarine cable system when transmitting the first detection light.

[0082] In step S242, a second gain spectrum of the first detected light in the submarine cable system is obtained as power variation data.

[0083] Wherein, the second gain spectrum includes the input spectrum and the output spectrum of the first detection light passing through each optical repeater. After transmitting the first detection light to the submarine cable system, the COTDR needs to obtain the return light of the first detection light, so as to obtain the transmission state of the first detection light in the submarine cable system through the return light. Therefore, in some embodiments of the present application, the second gain spectrum can be the spectrum of the return light of the first detection light, and if the spectrum of the return light coincides with the spectrum baseline, the transmission in the submarine cable system is normal, and if the spectrum of the return light does not coincide with the spectrum baseline, an abnormality occurs in the transmission in the submarine cable system.

[0084] In the above embodiment, by installing a COTDR and transmitting the first detection light, the transmission state in the submarine cable system can be acquired, and it is easy to determine whether it is necessary to calculate the first gain spectrum. Moreover, the detection light of a single wavelength can reduce the number of business channels occupied when monitoring and measuring the submarine cable system, thereby reducing the impact on the transmission efficiency of the submarine cable system when performing spectrum detection.

[0085] In step S250, a first gain spectrum is calculated based on the power change data, the spectral baseline and the gain change model.

[0086] The first gain spectrum includes the input spectrum and the output spectrum of each optical repeater after the power of the optical signal in the submarine cable system is changed, and the wavelength range of the optical signal in the first gain spectrum includes the entire service wavelength range occupied by the optical signal input to the submarine cable system.

[0087] In some of the above embodiments, the second gain spectrum in the submarine cable system is obtained by the first detection light, and the transmission state of the submarine cable system can be obtained by the relationship between the second gain spectrum and the spectral baseline. Therefore, in some of the embodiments, the step S250 of calculating the first gain spectrum based on the power variation data, the spectral baseline, and the gain variation model includes the following steps S251 to S252.

[0088] In step S251, if the second gain spectrum does not match the spectral baseline, the gain difference between the second gain spectrum and the spectral baseline is obtained.

[0089] After obtaining the second gain spectrum, it is compared with the spectrum of the corresponding wavelength in the spectrum baseline. If the second gain spectrum coincides with the spectrum baseline, it indicates that the optical signal transmission in the submarine cable system is normal and no power loss or other situations occur; if the second gain spectrum does not coincide with the spectrum baseline, it indicates that a transmission abnormality occurs in the submarine cable system, and the output spectrum of the submarine cable system also changes, and it is necessary to calculate the input and output spectrum of each optical repeater in the submarine cable system. The gain difference is the difference between the second gain spectrum and the spectrum corresponding to the first detected optical wavelength in the spectrum baseline, and is obtained by calculating the difference between the second gain spectrum and the spectrum baseline after obtaining the result that the second gain spectrum does not coincide with the spectrum baseline. If the gain difference is a positive value, it indicates that the gain data in the second gain spectrum is larger than the gain data in the spectrum baseline, and if the gain difference is a negative value, it indicates that the gain data in the second gain spectrum is smaller than the gain data in the spectrum baseline.

[0090] In some embodiments, the step S251 of obtaining the gain difference includes the steps of extracting gain spectrum information from the spectrum baseline, and comparing the second gain spectrum with the gain spectrum information to obtain the gain difference. The gain spectrum information includes the input spectrum and the output spectrum of the optical signal corresponding to the first detection wavelength in the spectrum baseline, which is passed through each optical repeater. When calculating the gain difference, the gain difference can be obtained by first extracting the baseline of the input spectrum and the output spectrum corresponding to the optical signal of the first detection wavelength in the spectrum baseline, and then calculating the difference based on the second gain spectrum and the gain spectrum information. In this embodiment, the gain difference of each optical repeater is calculated according to the corresponding relationship between each optical repeater and the spectrum baseline and the second gain spectrum, so as to obtain the spectrum change data of the submarine cable system, thereby improving the accuracy of spectrum acquisition.

[0091] In some embodiments of the present application, the second gain spectrum includes a second input spectrum and a second output spectrum, the gain spectrum information includes an input gain spectrum and an output gain spectrum, and the gain difference includes an input gain difference and an output gain difference, where the second input spectrum is an input spectrum of the first detection light corresponding to each optical repeater, the second output spectrum is an output spectrum of the first detection light corresponding to each optical repeater, the input gain spectrum represents spectral information corresponding to the first detection light wavelength in the input spectrum of each optical repeater on the spectral baseline, the output gain spectrum represents spectral information corresponding to the first detection light wavelength in the output spectrum of each optical repeater on the spectral baseline, the input gain difference is a difference between the second input spectrum and the input gain spectrum, and the output gain difference is a difference between the second output spectrum and the output gain spectrum.

[0092] After classifying the gain difference according to the input spectrum and the output spectrum, step S251 of acquiring the gain difference as shown in FIG. 9 may further include the following steps S2511 to S2513.

[0093] In step S2511, the difference between the second input spectrum and the input gain spectrum corresponding to each optical repeater is calculated to obtain an input gain difference.

[0094] In step S2512, the difference between the second output spectrum and the output gain spectrum corresponding to each optical repeater is calculated to obtain an output gain difference.

[0095] The process of calculating the input gain difference and the process of calculating the output gain difference are the same. In this embodiment, it is necessary to calculate the input gain difference and the output gain difference of each optical repeater. Even if the second gain spectrum and the gain spectrum information are consistent, it is necessary to obtain a gain difference whose value is 0, which makes it easier to arrange in subsequent steps.

[0096] In step S2513, the input gain difference and the output gain difference corresponding to each optical repeater are arranged in accordance with the transmission and reception order of each optical repeater to obtain the gain difference.

[0097] The gain difference is arranged in accordance with the transmission and reception sequence of each optical repeater, and the location where the fault has occurred in the submarine cable system can be determined based on the location where the gain difference is not zero.

[0098] Therefore, after obtaining the arranged gain difference, the fault location of the submarine cable system can be obtained based on the location of the gain difference, which specifically includes the following steps S2514 to S2516, as shown in FIG.

[0099] In step S2514, each input gain difference and output gain difference in the gain difference is detected to obtain first difference data that is larger than a first preset value or smaller than a preset value.

[0100] Among them, the preset numerical value may be 0, and the numerical values ​​of the input gain difference and the output gain difference being greater than 0 or less than 0 both indicate that there is a distinction between the second gain spectrum and the spectral baseline. Therefore, the step of acquiring the first difference data may include traversing each input gain difference and output gain difference corresponding to each optical repeater in the submarine cable system according to the transmission order of the first detection light, and taking the first gain difference greater than 0 or less than 0 as the first difference data.

[0101] In step S2515, if the first difference data is one input gain difference, the fault area of ​​the submarine cable system is the submarine cable connected to the input end of the first optical repeater.

[0102] Wherein, the first optical repeater is the optical repeater corresponding to the first difference data. Since each optical repeater in the submarine cable system has one input spectrum and one output spectrum, each optical repeater has a corresponding input gain difference and output gain difference, and the input gain difference and output gain difference in the gain difference are arranged according to the transmission and reception sequence of each optical repeater in the submarine cable system, so that the first difference data can be used to determine the area where the fault occurs in the submarine cable system.

[0103] For example, if the first difference data is a piece of input gain information, it indicates that a power change has occurred in the first detected light in the submarine cable before the first optical repeater, and therefore, the first difference data is a piece of input gain information, which can indicate that a fault has occurred in the submarine cable connected to the input end of the first optical repeater.

[0104] In step S2516, if the first difference data is one output gain difference, the fault area of ​​the submarine cable system is the first optical repeater.

[0105] If the first difference data is an output gain difference, it indicates that a power change occurs during the amplification process of the first detected light in the first optical repeater, and therefore, the first difference data is an output gain difference, which can indicate that the fault area of ​​the submarine cable system is the first optical repeater.

[0106] As can be seen from the above embodiments, by determining whether the first gain difference is an input gain difference or an output gain difference, the location of the area where a fault has occurred in the submarine cable system can be determined, which makes it easier to investigate and maintain the fault. Moreover, since only the input spectrum and the output spectrum corresponding to the optical repeater after the fault area change, by determining the fault area, the number of input spectra and output spectra that need to be calculated can be reduced, and the efficiency of spectrum acquisition can be improved.

[0107] In step S252, a first gain spectrum is calculated based on the gain difference and the gain variation model.

[0108] After obtaining the gain difference, the gain difference can be substituted into the gain variation model to determine the type of fault that has occurred in the submarine cable system, and the first gain spectrum corresponding to each optical repeater can be calculated using the gain variation model in the above embodiment.

[0109] For example, in some embodiments, after determining a fault region of a submarine cable system, input and output spectra corresponding to each optical repeater after the fault region are obtained, thereby reducing the number of input and output spectra that need to be obtained when calculating the first gain spectrum, and improving the efficiency of spectrum calculation. Therefore, as shown in FIG. 9, step S252 of calculating the first gain spectrum includes the following steps S2521 to S2522.

[0110] In step S2521, a second optical repeater in the submarine cable system is determined based on the location of the first optical repeater.

[0111] Among them, the second optical repeater includes each optical repeater connected to the output end of the first optical repeater via the undersea cable. After determining the position of the first optical repeater in the undersea cable system, each optical repeater after the output end of the first optical repeater is determined as the second optical repeater according to the connection order of the optical repeaters in the undersea cable system.

[0112] In addition, since the second optical repeater is an optical repeater connected to the output end of the first optical repeater, when the output end of the first optical repeater is connected to a terminal device in the submarine cable system, the second optical repeater does not exist in the submarine cable system, and when calculating the first gain spectrum, only the input spectrum and output spectrum corresponding to the first optical repeater can be calculated.

[0113] In step S2522, the input spectrum and the output spectrum of each second optical repeater are calculated based on the gain difference and the gain change model corresponding to the second optical repeater to obtain a first gain spectrum.

[0114] After determining the second optical repeater, the input gain difference and output gain difference corresponding to each second optical repeater can be substituted into the gain change model to calculate the input spectrum and output spectrum of each second optical repeater, thereby obtaining the first gain spectrum.

[0115] In addition, when calculating the first gain spectrum, since the input spectrum and / or output spectrum corresponding to the first optical repeater also has a power change, the first gain spectrum can be obtained by arranging the input spectrum and output spectrum corresponding to the first optical repeater and the second optical repeater in accordance with the connection order.

[0116] For example, after the submarine cable system is put into operation, a first detection light having a single wavelength is transmitted to the submarine cable system to obtain a second gain spectrum corresponding to the first detection light, thereby obtaining a gain spectrum of an optical repeater RPT in the submarine cable system, as shown in FIG. m+1 The power of the optical signal received by the RPT decreases.m The optical signal transmitted by the optical repeater RPT is normal. m and RPT m+1 It can be seen that a situation has occurred in which loss has increased in the undersea cable between, and therefore, by substituting the power change into a gain change model, the input and output spectra of the optical repeater can be calculated.

[0117] Specifically, in this embodiment, the input spectrum and the output spectrum are calculated by the gain variation model as follows.

[0118] First, the location where the loss increased was the optical repeater RPT. m and RPT m+1 It is a submarine cable between m Since the input and output spectra of RPT m The input and output spectra of are unchanged.

[0119] Next, RPT m+1 The input spectrum of RPT m The output spectrum of is the data after the loss caused by passing through the undersea cable between the two, and the formula (5) is expressed as follows.

[0120]

number

[0121] Here, S m+1-in is RPT m+1 is the input spectrum of S m-out is RPT m is the output spectrum of S m-Loss is RPT m and RPT m+1 is the loss spectrum of the undersea cable between m and RPT m+1 The increased loss due to the undersea cable between

[0122] RPTm+1 Since the output spectrum of the filter undergoes a slope change caused by the deviation from the nominal power due to the power change of the input spectrum, the formula (6) can be expressed as follows:

[0123]

number

[0124] Here, S m+1-out is RPT m+1 is the output spectrum of P m-base is RPT m is the nominal power of k m-base is RPT m is the nominal slope of Δ m k1 is RPT m and RPT m+1 RPT due to increased losses in undersea cables between m+1 is the change in the slope of the output spectrum, Δ m k4 is RPT m and RPT m+1 This is the change in the slope of the undersea cable loss spectrum due to an increase in the loss of the undersea cable between the two. In this way, the input and output spectra of each subsequent stage of optical repeater can be obtained.

[0125] In the coordinate diagram shown in FIG. 10, the ordinate is power and the abscissa is the distance of the submarine cable system. That is, after transmitting the first detection light, the power of the first detection light changes as the distance of the submarine cable system increases, and the power increase portion is the result of the first detection light passing through the optical repeater and being amplified by the optical repeater, while the power decrease portion is a gradual decrease in power due to losses caused by scattering, absorption, etc. in the submarine cable while the first detection light is transmitted through the submarine cable between both optical repeaters.

[0126] In some other embodiments of the present application, when a pump failure occurs in an optical repeater in a submarine cable system, it can be determined according to the spectrum conditions of the optical repeaters one before and one after the optical repeater in which the pump failure occurs.m After pump failure occurs, as shown in Figure 11, the failed optical repeater has a reduced gain for the optical signal, and the power of the output optical signal cannot reach the level of the spectrum baseline, resulting in RPT. m-1 , R.P.T. m and RPT m+1 The second gain spectrum change situation of RPT m The state of each optical repeater is judged, and the input spectrum and output spectrum of each optical repeater are calculated. Note that the horizontal and vertical coordinates of the coordinate diagram in Fig. 11 are the same as those in Fig. 10, so the explanation thereof will be omitted in this embodiment.

[0127] Specifically, in this embodiment, the input spectrum and the output spectrum are calculated by the gain variation model as follows.

[0128] First, RPT m Pump failure issue occurs in RPT m-1 is not affected by this, so RPT m The input spectrum remains at baseline.

[0129] RPT m The output spectrum of the pump is calculated by the power change due to its own pump cancellation, Δ m P EDFA and the change in slope Δ m Influenced by k3, the formula (7) is expressed as follows:

[0130]

number

[0131] In addition, at this time, RPT m The output power of the RPT m From RPT m+1 The slope of the loss spectrum of the undersea cable between the two terminals changes, and the equation (8) is expressed as follows:

[0132]

number

[0133] Here, S m-base-Loss is RPT m From RPT m+1 is the basic loss for the optical signal in the undersea cable between m k4 is RPT m From RPT m+1 This is the change in the slope of the loss spectrum due to the change in the input power of the submarine cable between

[0134] RPT m+1 The input spectrum of RPT m This is the data of the output spectrum after it has been lost while passing through the undersea cable between the two, and the formula (9) is expressed as follows.

[0135]

number

[0136] Also, RPT m+1 The output spectrum of the m ) slope change Δ caused by power change due to pump failure m k1 and the slope change due to the failure of the previous stage pump Δ m Influenced by k2, the formula (10) is expressed as follows:

[0137]

number

[0138] In this way, the input and output spectra of each subsequent stage of repeater can be obtained.

[0139] In the above embodiment, after the fault location of the submarine cable system is obtained, the input and output spectra of each optical repeater subsequently connected to the fault location are calculated to obtain the spectral changes of the submarine cable system, thereby reducing the amount of calculation and improving the efficiency of spectrum acquisition.

[0140] In some embodiments of the present application, after the first gain spectrum is obtained, the first gain spectrum can be further displayed on a display device. By displaying the spectrum change in this manner, information such as the location and cause of the fault can be presented to maintenance staff, making it easier to maintain the submarine cable system.

[0141] According to the above embodiment, after a power change occurs in a submarine cable system, the input spectrum and output spectrum of each affected optical repeater can be calculated and obtained, thereby obtaining the gain spectrum corresponding to each optical repeater in the submarine cable system, and improving the accuracy of spectrum acquisition.

[0142] Based on the above-mentioned spectrum detection method for a submarine cable system, the present application provides a spectrum detection system for a submarine cable system for performing any of the above-mentioned spectrum detection methods for a submarine cable system, the spectrum detection system being installed in the submarine cable system, as shown in FIG. 12, the submarine cable system includes a plurality of terminal stations A to E, a submarine cable and a plurality of optical repeaters, the plurality of terminal stations A to E are configured to transmit and receive optical signals, the submarine cable is installed between the plurality of terminal stations A to E to connect the plurality of terminal stations A to E, and the plurality of optical repeaters are installed in the submarine cable respectively to amplify the optical signals transmitted from the terminal stations A to E, as shown in FIG. 13, the system includes a network management device 1310 and a submarine cable monitoring and measurement device 1320, the network management device 1310 is installed in one terminal station and connected to another terminal station, the submarine cable monitoring and measurement device 1320 is connected to the submarine cable, and the network management device 1310 is connected to the submarine cable monitoring and measurement device 1320. Wherein, the network management device 1310 includes a data collection unit 1311 and a processing calculation unit 1312. Wherein, the data collection unit 1311 is configured to obtain first spectrum test data of a plurality of optical repeaters and second spectrum test data of a submarine cable. The processing calculation unit 1312 is configured to obtain a spectrum baseline corresponding to each optical repeater according to each of the first spectrum test data and the second spectrum test data, and obtain a gain change model corresponding to each optical repeater according to each of the first spectrum test data.

[0143] The submarine cable monitoring and measuring device 1320 is configured to monitor and measure the submarine cable system to obtain power variation data. After the submarine cable monitoring and measuring device 1320 monitors and measures the power variation data in the submarine cable system, the submarine cable monitoring and measuring device 1320 can transmit the data to the processing and computing unit 1312, where the processing and computing unit 1312 is further configured to calculate a first gain spectrum according to the power variation data, the spectrum baseline and the gain variation model. In some embodiments, the network management device 1310 may further include a data storage unit 1314, which can store the obtained data after the data collection unit 1311 obtains the first spectrum test data and the second spectrum test data, for the processing and computing unit 1312 to call in subsequent processing.

[0144] As can be seen from the above-mentioned embodiments, the submarine cable monitoring and measuring device 1320 can be a COTDR device capable of transmitting detection light of a single wavelength, and the COTDR is respectively connected to the submarine cable and the network management device 1310, thereby transmitting a first detection light to the submarine cable to monitor and measure the transmission status of the submarine cable system, and transmitting the results obtained by the monitoring and measuring to the network management device 1310.

[0145] As can be seen from the above embodiment, by respectively installing a network management device 1310 and a submarine cable monitoring and measuring device 1320 in the submarine cable system, the spectrum of the submarine cable system can be calculated, in which the submarine cable monitoring and measuring device 1320 can monitor and measure the submarine cable system to obtain power change data of the submarine cable system, and the network management device 1310 can obtain and process the first spectrum test data and the second spectrum test data to obtain a spectrum baseline of the submarine cable system and a gain change model corresponding to the optical repeater, so as to calculate the gain spectrum corresponding to each optical repeater after a power change occurs in the submarine cable system, and improve the accuracy of the obtained gain spectrum.

[0146] In some embodiments of the present application, as shown in Fig. 13, the network management device 1310 further includes a spectrum display unit 1313 configured to display the first gain spectrum. By installing the spectrum display unit 1313 in the network management device 1310, after the first gain spectrum is calculated and obtained, the first gain spectrum can be displayed, thereby reminding the maintenance staff to maintain the submarine cable system.

[0147] As can be seen from the above technical configuration, the present application provides a spectrum detection method and system for a submarine cable system, which is applied to a submarine cable system including a plurality of terminals, a submarine cable and a plurality of optical repeaters, the method comprising the steps of: obtaining first spectrum test data and second spectrum test data, and obtaining a spectrum baseline corresponding to each optical repeater based on the obtained data; obtaining a gain change model corresponding to each optical repeater based on each of the first spectrum test data; obtaining power change data by monitoring and measuring the submarine cable system, and calculating a first gain spectrum based on the power change data, the spectrum baseline and the gain change model, wherein the first spectrum test data includes shipment spectrum test data of each optical repeater, the second spectrum test data includes inherent Raman spectrum data of the submarine cable, the spectrum baseline includes an input spectrum and an output spectrum during normal operation of the submarine cable system, the gain change model includes gain data of the optical repeater for optical signals of different wavelengths and / or different powers, and the first gain spectrum includes an input spectrum and an output spectrum of each optical repeater after a power change of the optical signal in the submarine cable system. With this method, when an abnormality occurs in the transmission power in a submarine cable system, the spectrum after the change in each optical repeater is calculated using a gain change model, and the input spectrum and output spectrum corresponding to each optical repeater are obtained, thereby improving the accuracy of spectrum acquisition.

[0148] Similar parts between the embodiments of the present application may be referred to each other, and the specific embodiments provided above are merely some examples in the overall concept of the present application, and do not limit the scope of protection of the present application. For those skilled in the art, any other embodiments extended based on the solutions of the present application without any creative effort belong to the scope of protection of the present application.

Claims

1. 1. A spectrum detection method for a submarine cable system, which is applied to a submarine cable system including a plurality of terminal stations configured to transmit and receive optical signals, a submarine cable installed between the plurality of terminal stations to connect the plurality of terminal stations, and a plurality of optical repeaters installed on the submarine cable, respectively, for amplifying optical signals transmitted from the terminal stations, comprising: acquiring first spectral test data for a plurality of the optical repeaters and second spectral test data for the submarine cable, the first spectral test data including shipment spectral test data for each of the optical repeaters, and the second spectral test data including characteristic Raman spectral data for the submarine cable; obtaining a spectral baseline corresponding to each of the optical repeaters based on each of the first spectral test data and the second spectral test data, the spectral baseline including an input spectrum and an output spectrum of each of the optical repeaters after the submarine cable system inputs an optical signal of a preset power; obtaining a gain variation model corresponding to each of the optical repeaters based on each of the first spectrum test data, the gain variation model including gain data of the optical repeaters for optical signals of different wavelengths and / or different powers; monitoring said submarine cable system to obtain power variation data; calculating a first gain spectrum based on the power change data, the spectral baseline and the gain change model, the first gain spectrum including an input spectrum and an output spectrum of each of the optical repeaters after a power change of an optical signal in the submarine cable system; 13. A method for spectrum detection in a submarine cable system comprising:

2. The step of obtaining a spectral baseline corresponding to each of the optical repeaters based on the first spectral test data and the second spectral test data includes: obtaining a wavelength range of an input optical signal of the submarine cable system and power information corresponding to different wavelength signals; obtaining a loss spectrum for the input optical signal of the submarine cable and a gain spectrum for the input optical signal of each of the optical repeaters based on the wavelength range and the power information; determining the loss spectrum and the gain spectrum corresponding to the input optical signal as the spectral baseline; 2. The method of claim 1, wherein the spectrum of a submarine cable system is detected by the first submarine cable.

3. The step of obtaining a gain variation model corresponding to each of the optical repeaters based on each of the first spectrum test data includes: obtaining gain data for optical signals of different wavelengths and / or different powers for each of the optical repeaters based on the first spectrum test data; determining the gain change model corresponding to each of the optical repeaters based on gain data corresponding to each of the optical repeaters; 2. The method of claim 1, wherein the spectrum of a submarine cable system is detected by the first submarine cable.

4. The step of monitoring and measuring the submarine cable system to obtain power variation data includes: transmitting a first detection light of a single wavelength onto the undersea cable system; acquiring a second gain spectrum of the first detected light in the submarine cable system as the power change data, the second gain spectrum including an input spectrum and an output spectrum of the first detected light passing through each of the optical repeaters; Calculating a first gain spectrum based on the power change data, the spectral baseline and the gain change model, comprising: if the second gain spectrum does not coincide with the spectral baseline, obtaining a gain difference between the second gain spectrum and the spectral baseline; calculating the first gain spectrum based on the gain difference and the gain variation model.

2. The method of claim 1, wherein the spectrum of a submarine cable system is detected by the first submarine cable.

5. If the second gain spectrum does not coincide with the spectral baseline, obtaining a gain difference between the second gain spectrum and the spectral baseline comprises: extracting gain spectrum information from the spectral baseline, the gain spectrum information including an input spectrum and an output spectrum of an optical signal corresponding to a first detection optical wavelength in the spectral baseline passed through each of the optical repeaters; comparing the second gain spectrum with the gain spectrum information to obtain the gain difference.

5. The method of claim 4, wherein the spectrum of a submarine cable system is detected by the spectrum detector.

6. the second gain spectrum includes a second input spectrum and a second output spectrum, the gain spectrum information includes an input gain spectrum and an output gain spectrum, and the gain difference includes an input gain difference and an output gain difference, and the step of comparing the second gain spectrum with the gain spectrum information to obtain the gain difference includes: calculating a difference between the second input spectrum and the input gain spectrum corresponding to each of the optical repeaters to obtain an input gain difference; calculating a difference between the second output spectrum and the output gain spectrum corresponding to each of the optical repeaters to obtain an output gain difference; and arranging the input gain difference and the output gain difference corresponding to each of the optical repeaters according to a transmission / reception order of each of the optical repeaters to obtain the gain difference.

6. The method of claim 5, wherein the spectrum of a submarine cable system is detected by the spectrum detector.

7. After the step of comparing the second gain spectrum with the gain spectrum information to obtain a gain difference, Detecting each of the input gain difference and the output gain difference in the gain difference to obtain first difference data that is greater than a first preset value or smaller than the preset value; If the first difference data is one of the input gain differences, a fault area of ​​the submarine cable system is the submarine cable connected to an input end of a first optical repeater corresponding to the first difference data; If the first difference data is one of the output gain differences, the fault area of ​​the submarine cable system is the first optical repeater.

7. The method of claim 6, wherein the spectrum of a submarine cable system is detected by the submarine cable.

8. The step of calculating the first gain spectrum based on the gain difference and the gain variation model includes: determining a second optical repeater in the submarine cable system based on a position of the first optical repeater, the second optical repeater including each of the optical repeaters connected to an output end of the first optical repeater via the submarine cable; calculating an input spectrum and an output spectrum of each of the second optical repeaters based on the gain difference corresponding to the second optical repeater and the gain change model to obtain the first gain spectrum; 8. The method of claim 7, wherein the spectrum of a submarine cable system is detected by the submarine cable.

9. After the step of calculating the first gain spectrum, displaying the first gain spectrum.

2. The method of claim 1, wherein the spectrum of a submarine cable system is detected by the first submarine cable.

10. 10. A spectrum detection system for a submarine cable system, comprising: a plurality of terminal stations configured to transmit and receive optical signals; a submarine cable installed between said plurality of terminal stations to connect said plurality of terminal stations; and a plurality of optical repeaters installed in said submarine cable system, each of said optical repeaters amplifying optical signals transmitted from said terminal stations, said spectrum detection system being installed in a submarine cable system for use in carrying out the spectrum detection method for a submarine cable system according to any one of claims 1 to 9, The spectrum detection system includes a network management device installed at one end station and connected to another end station, and a submarine cable monitoring and measurement device connected to the submarine cable and the network management device; The network management device a data collection unit configured to acquire first spectral test data of the plurality of optical repeaters and second spectral test data of the submarine cable; a processing and calculation unit configured to obtain a spectral baseline corresponding to each of the optical repeaters based on each of the first spectral test data and the second spectral test data, and to obtain a gain change model corresponding to each of the optical repeaters based on each of the first spectral test data; The submarine cable monitoring and measurement device is configured to monitor and measure the submarine cable system to obtain power variation data; the processing and computing unit is further configured to calculate a first gain spectrum based on the power variation data, the spectral baseline and the gain variation model.

1. A spectrum detection system for a submarine cable system comprising:

11. the network management device further comprises a spectrum display unit configured to display the first gain spectrum. A submarine cable system spectrum detection system according to claim 10.

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