Underwater equipment and communication system

Abstract

To provide underwater equipment and a communication system, each enabling improvement of a service life of a submarine cable optical fiber communication system by installing backup pump laser.SOLUTION: Underwater equipment 100 includes a first optical fiber 110, a second optical fiber 120, a conventional pump laser 101, and at least one backup pump laser 102. The conventional pump laser 101 is used for providing pump light for a first optical amplification unit 150 located at the first optical fiber 110 and a second optical amplification unit 160 located at the second optical fiber 120. The backup pump laser 102 is used for performing output power compensation when an output power of the conventional pump laser 101 is less than a target output power. Each of the conventional pump laser 101 and the backup pump laser 102 are coupled to an input port of an optical device 130.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This application relates to the field of optical communication technologies, and particularly to underwater devices and communication systems.

Background Art

[0002] As an important international communication means, submarine cable communication systems are usually required to provide services for 25 years in the industry. However, in reality, submarine cable communication systems face the problem of performance degradation of the system due to device aging in the middle and later stages of the service life. The optical repeater of the submarine cable communication system mainly adopts EDFA (Erbium Doped Fiber Amplifier) optical amplification technology. In a communication system composed of optical fiber amplifiers, the aging of the pump laser is one of the main sources causing performance degradation of the submarine cable communication system.

[0003] In the middle and later stages of the service life of the submarine cable communication system, the aging of the pump laser causes a decrease in the output power of the optical repeater, and the increase in loss due to the aging of other optical devices and the aging of the circuit optical fiber is superimposed, causing performance degradation of the circuit OSNR (Optical Signal Noise Ratio), and in serious cases, even causing service interruption.

[0004] When the pump laser ages, construction and maintenance can be carried out on the submarine cable communication system, additional optical repeaters can be added to the circuit to improve the optical power of the circuit, and the performance degradation of the system due to aging can be improved. However, in the maintenance process, it is necessary for the working ship to cut the submarine cable for maintenance. Since the maintenance time is long, it causes service interruption of the entire system, and moreover, the later maintenance cost is high.

Summary of the Invention

Problems to be Solved by the Invention

[0005] This application provides an underwater device (submerged device) and a communication system, and solves the problem that when the performance of the pump laser in a submarine cable communication system deteriorates, the pump output power fails to meet the output requirement, and the service life of the submarine cable communication system fails to meet the standard.

Means for Solving the Problem

[0006] In a first aspect, some embodiments of this application provide an underwater device, which includes a first optical fiber, a second optical fiber, a normal pump laser, and at least one backup pump laser. The normal pump laser is used to provide pump light to a first optical amplification unit located in the first optical fiber and a second optical amplification unit located in the second optical fiber. The normal pump laser and the backup pump laser are respectively connected to the input ports of the optical devices of the first optical fiber and / or the second optical fiber. Among them, the optical device is used to optically couple the normal pump laser and the backup pump laser. The backup pump laser is used to compensate the output power when the output power of the normal pump laser is smaller than the target output power. Among them, the compensated output power is the output power lost by the normal pump laser in an aging state. The backup pump laser is arranged to be in an off state until a first command is received, and is started to output pump light when the first command is received. Among them, The first command is a control command transmitted when the output power of the normal pump laser is smaller than the target output power. By installing at least one backup pump laser in the underwater device, this application can start the backup pump laser to compensate the pump output power of the underwater device when the normal pump laser ages, and improve the service life of the submarine cable optical fiber communication.

[0007] In some feasible embodiments, the backup pump laser is further arranged to be in an off state before a second command is received, and to be activated to output pump light when the second command is received, where the second command is a control command transmitted when the aging value of the underwater device is greater than a threshold value. The underwater device can compare the calculated aging value with the threshold value, and when the aging value of the underwater device is greater than the threshold value, activate the backup pump laser to make the pump output power meet the output requirement.

[0008] In some feasible embodiments, the normal pump laser includes a first pump laser and a second pump laser connected to the backup pump laser. The input port of the first optical fiber coupler of the first optical fiber is connected to the first pump laser, and the output port of the first optical fiber coupler of the first optical fiber is connected to the first optical amplification unit. The second pump laser and the backup pump laser are respectively connected to the input port of the optical device of the second optical fiber. The output port of the optical device of the second optical fiber is connected to the second optical amplification unit. The first pump laser is used to provide pump light to the first optical amplification unit located in the first optical fiber, and the second pump laser is used to provide pump light to the second optical amplification unit located in the second optical fiber. The number of backup pump lasers arranged can be selected to be arranged in a certain proportion of the normal pump lasers after evaluating the device reliability and system performance. By arranging the backup pump lasers periodically, some of the backup pump lasers can be selectively activated to reduce costs.

[0009] In some feasible embodiments, the underwater device includes at least two first pump lasers and two second pump lasers. Each of the first pump lasers provides 50% of the energy to the first optical amplification unit, and each second pump laser provides 50% of the energy to the second optical amplification unit. Alternatively, the underwater device includes at least four first pump lasers and four second pump lasers. Each of the first pump lasers provides 25% of the energy to the first optical amplification unit, and each second pump laser provides 25% of the energy to the second optical amplification unit. A pump redundant optical path is arranged in the underwater device. The two normal pump lasers are redundant to each other. When one normal pump laser fails, the other normal pump laser provides pump light and simultaneously activates a backup pump laser in a single fiber pair 2×2 or 4×4 pump redundant optical path, so as to improve the pump power of all EDFA circuits through the 2×2 or 4×4 pump redundant optical path.

[0010] In some feasible embodiments, the backup pump laser is connected to only one of the second pump lasers among the plurality of second pump lasers of the underwater device. Among them, the newly added backup pump laser is used to compensate only for the reduced pump power due to aging. The backup pump laser is connected to only one of the normal pump lasers among the plurality of normal pump lasers of the underwater device, which can compensate the pump output power and reduce the cost.

[0011] In some feasible embodiments, the first optical fiber and the second optical fiber belong to the same optical fiber pair, or the first optical fiber and the second optical fiber belong to different optical fiber pairs. The first optical fiber can be used to transmit an optical signal to the onshore base station at the opposite end, and the second optical fiber can be used to receive the optical signal transmitted from the onshore base station at the opposite end.

[0012] In some feasible embodiments, the optical device is a polarization beam combiner or an optical switch. A normal pump laser and a backup pump laser can perform optical coupling by means of a polarization beam combiner, and further, a strobe can be performed on the pump laser and the backup pump laser by using an optical switch.

[0013] In some feasible embodiments, one backup pump laser is arranged for each of the normal pump lasers, and the normal pump lasers and the backup pump lasers are coupled by a polarization beam combiner or an optical switch. By arranging backup pump lasers for all the normal pump lasers of all the underwater devices in the entire circuit, the space and granularity (accuracy) of the performance adjustment of the entire underwater device communication system can be made better.

[0014] In some feasible embodiments, the underwater device is an optical repeater. By adding a backup pump laser to the optical repeater to compensate for the reduced output power due to the aging of the normal pump laser and improve the aging situation of the pump laser, the output power of the optical repeater can be made to meet the operating requirements, the optical signal-to-noise ratio of the optical repeater can be stably maintained, and the stability of the transmission performance can be maintained.

[0015] In a second aspect, the present application further provides an underwater device communication system, including the underwater device described in the first aspect, a first station used for transmitting a first data optical signal to the underwater device via the first optical fiber, and a second station used for transmitting a second data optical signal to the underwater device via the second optical fiber, and further includes, after receiving the first data optical signal, the underwater device is used for amplifying the first data optical signal and then outputting the amplified signal to the second station, and after receiving the second data optical signal, the underwater device is used for amplifying the second data optical signal and then outputting the amplified signal to the first station.

Advantages of the Invention

[0016] As can be seen from the above technical solutions, some embodiments of the present application provide an underwater device and a communication system. The underwater device includes a first optical fiber, a second optical fiber, a normal pump laser, and at least one backup pump laser. The normal pump laser is used to provide pump light to a first optical amplification unit located in the first optical fiber and a second optical amplification unit located in the second optical fiber. The normal pump laser and the backup pump laser are respectively connected to the input ports of the optical devices of the first optical fiber and / or the second optical fiber. Among them, the optical device is used to optically couple the normal pump laser and the backup pump laser. The backup pump laser is used to compensate for the output power when the output power of the normal pump laser is smaller than the target output power. Among them, the compensated output power is the output power lost by the normal pump laser in the aging state. The backup pump laser is in an off state until a first command is received, and is arranged to be activated to output pump light when the first command is received. Among them, the first command is a control command transmitted when the output power of the normal pump laser is smaller than the target output power. By installing at least one backup pump laser in the underwater device, when the normal pump laser ages, the backup pump laser can be activated to compensate for the pump output power of the underwater device, thereby improving the service life of the submarine cable optical fiber communication.

Brief Description of the Drawings

[0017] To more clearly illustrate the technical solutions of the present application, the drawings that need to be used in the following embodiments are briefly introduced. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

Figure 1

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Figure 5

Embodiments for Carrying Out the Invention

[0018] Hereinafter, the technical solution of the present invention will be clearly and completely described in connection with embodiments. Obviously, the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art on the premise of not performing creative labor based on the embodiments of the present invention belong to the protection scope of the present invention.

[0019] The terms "first" and "second" are used merely for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features limited by "first" and "second" may explicitly or implicitly include one or more of the above features. In the description of the present invention, the meaning of "a plurality" is two or more unless specifically and clearly limited otherwise. Also, the terms "attach", "connect", "couple" should be understood in a broad sense. For example, it may be a fixed connection, a removable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, or a communication inside two elements. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific situation.

[0020] An underwater communication system is a system laid in environments such as the seabed or lake bottom to achieve long-distance data communication. Exemplarily, the underwater communication system can include a submarine cable communication system.

[0021] As shown in FIG. 1, as an important international communication means, the submarine cable communication system is usually required to provide services for 25 years in the industry. However, in reality, the submarine cable communication system faces the problem of performance degradation of the system due to the aging of devices in the mid- to late-stage of the service life. The optical repeater of the submarine cable communication system mainly adopts EDFA (Erbium Doped Fiber Amplifier) optical amplification technology. In a communication system composed of optical fiber amplifiers, the aging of the pump laser is one of the main sources causing the performance degradation of the submarine cable communication system.

[0022] In the mid- to late-stage of the service life of the submarine cable communication system, the aging of the pump laser causes a decrease in the output power of the optical repeater, and the increase in loss due to the aging of other optical devices and the aging of the circuit optical fiber is superimposed, causing performance degradation of the circuit OSNR (Optical Signal Noise Ratio) optical signal-to-noise ratio, and in serious cases, even causing service interruption.

[0023] In related technologies, by adopting a significant derating design for the pump laser, the aging trend of the pump device is suppressed, thereby extending the service life of submarine cable optical fiber communication. To limit the output current and output power of the pump laser, the performance of the device itself cannot be fully utilized, causing waste of device performance, and in serious cases, the system cannot even operate at the optimal performance point.

[0024] In related technologies, when the pump laser ages, construction and maintenance can be performed on the submarine cable communication system. An extra optical repeater is added to the circuit to improve the optical power of the circuit and to improve the performance degradation of the system due to aging. However, in the maintenance process, it is necessary for the work ship to cut the submarine cable for maintenance, which not only causes the interruption of the entire system's services, but also results in a long maintenance time and extremely high later-stage maintenance costs.

[0025] When the performance of the pump laser in the submarine cable communication system deteriorates and the pump output power fails to meet the output requirements, and the service life of the submarine cable communication system fails to meet the standards, some embodiments of the present application provide an underwater device, and at least one backup pump laser is installed in the underwater device. When the normal pump laser ages, the backup pump laser is activated to compensate for the pump output power of the underwater device, and the service life of the submarine cable optical fiber communication can be improved.

[0026] Some embodiments of the present application provide an underwater device 100, and the underwater device 100 includes a first optical fiber 110, a second optical fiber 120, a normal pump laser 101, and at least one backup pump laser 102. The normal pump laser 101 is used to provide pump light to a first optical amplification unit 150 located in the first optical fiber 110 and a second optical amplification unit 160 located in the second optical fiber 120. The normal pump laser 101 and the backup pump laser 102 are respectively connected to the input ports of the optical device 130 of the first optical fiber 110 and / or the second optical fiber 120. Among them, the optical device 130 is used to optically couple the normal pump laser 101 and the backup pump laser 102. The backup pump laser 102 is used to compensate for the output power when the output power of the normal pump laser 101 is smaller than the target output power. Among them, the compensated output power is the output power lost by the normal pump laser 101 in the aging state. Note that the normal pump laser 101 operates normally throughout the service stage of the communication system, but the backup pump laser 102 does not operate at the initial stage of the communication system service. It is activated when a control command transmitted from the underwater device 100 is received, or is activated based on an activation command transmitted from the ground base station.

[0027] In some embodiments, the backup pump laser 102 is arranged to be in an off state until a first command is received, and is activated to output pump light when the first command is received. Among them, the first command is a control command transmitted when the output power of the normal pump laser 101 is smaller than the target output power. The underwater device 100 can detect the output power of the normal pump laser 101 or the underwater device 100 in real time, and activates the backup pump laser 102 when the output power is smaller than the target output power.

[0028] In some embodiments, the backup pump laser 102 is further arranged to be in an off state until a second command is received, and is activated to output pump light when the second command is received. Among them, the second command is a control command transmitted when the aging value of the underwater device 100 is larger than a threshold value. The underwater device 100 can further activate the backup pump laser 102 when the calculated aging value is larger than the threshold value. Among them, the priorities of the first command and the second command may be the same, the priorities of the first command and the second command may be different, or they may not be distinguished.

[0029] Among them, the aging value of the underwater device 100 can be obtained based on means such as the symbol error rate, optical signal-to-noise ratio, and loopback signal power of the underwater device 100.

[0030] Note that the symbol error rate, that is, the bit error rate, is the ratio of the number of bits in error to the total number of bits after converting an electrical signal into an optical signal, transmitting it in a WDM wavelength division system, reaching the link end, and the receiver converting the optical signal into an electrical signal. The bit error rate is the final value for assessing the transmission quality. In some embodiments, the underwater device 100 detects the symbol error rate of the system service performance in real time. If the symbol error rate of the system service performance increases, that is, the aging degree of the system increases.

[0031] Note that the optical signal-to-noise ratio is defined as the ratio of the optical signal power to the noise power within an optical effective bandwidth of 0.1 nm. In some embodiments, the ground station can determine whether the system is aging based on the change in the optical signal-to-noise ratio (OSNR) of the received-end service optical signal, monitor the OSNR change trend in real time, or periodically test and compare the OSNR changes to predict the system aging trend.

[0032] In some embodiments, by using an OTDR (Optical Time Domain Reflectometry) device or a COTDR (Coherent Optical Time Domain Reflectometry) device arranged at a ground station, the gain change of the RPT optical repeater can be intuitively detected. Based on the RPT gain change, it is possible to determine whether the pump laser has aged. The test principle of OTDR (Optical Time Domain Reflectometry) is to apply pulse modulation to a laser and send the test light to the optical transmission circuit to be measured by an optical directional coupler capable of separating the emitted light and the received light. Due to the action of Rayleigh scattering, the backscattered light returned from each part of the optical fiber (including the non-uniformity of the optical fiber, optical connectors, optical fiber joints, optical fiber faults or breakpoints) displays a continuous signal on the time base of the screen, that is, the near part first and the far part later, and its intensity is proportional to the transmitted optical power at each point. As is obvious, the backscattered light is separated and received by the optical coupler, the horizontal axis is corresponded to the time sequence when the backscattered light arrives in the form of distance, the intensity of the scattered light is displayed in dB on the vertical axis and shown on the screen, the optical pulse round-trip time on the horizontal axis is converted into a scale of the optical fiber length, and it is used to observe the change state of the optical power transmitted along the entire optical fiber circuit directly.

[0033] Note that the COTDR (Coherent Optical Time Domain Reflectometry) technology is a method for monitoring and measuring the underwater part of a submarine cable communication system. By emitting a probe optical pulse signal to the optical fiber, when the optical pulse is transmitted in the optical fiber, backscattered Rayleigh light continues to be generated along the optical fiber. Reflections occur at connectors, mechanical connections, breaks or the ends of the optical fiber. A part of the backscattered Rayleigh light and the reflected light are transmitted in the reverse direction along the optical fiber and return to the emission side, and are received by the probe of the COTDR meter. By the change in the intensity of the received optical pulse, the operating state of the submarine optical cable and the repeater can be determined.

[0034] In some embodiments, an optical fiber coupler 140 is respectively connected to the output end of the optical amplification unit of the underwater device 100. The optical fiber coupler 140 includes a first optical fiber coupler located on the first optical fiber 110 and a second optical fiber coupler located on the second optical fiber 120. Among them, the first optical fiber coupler located on the first optical fiber 110 receives a first reflected optical signal and is used to send a part of the first reflected optical signal to the second optical fiber coupler located on the second optical fiber 120. Among them, the first reflected optical signal is obtained after the amplified first detection optical signal passes through backscattering. The second optical fiber coupler located on the second optical fiber 120 receives the part of the first reflected optical signal output from the first optical fiber coupler and is used to transmit the part of the first reflected optical signal in the direction of the first station 200. Adding an optical fiber coupler 140 to the output end of the first optical amplification unit 150 or the second optical amplification unit 160 of the underwater device 100 does not cause deterioration of the noise coefficient of the underwater device 100. By making a coupling connection between each pair of optical fibers inside the underwater device 100, that is, installing a loopback path, the backscattering and / or reflected optical signal of the probe optical signal incident on the uplink can be coupled to the downlink, transmitted along the downlink optical fiber, and amplified by the downlink optical amplification unit when passing through the underwater device 100, and then transmitted in the reverse direction and returned to the ground station. The probe of the COTDR meter can receive the probe optical signal more easily, and the COTDR meter can detect the problem of aging or failure of the normal pump laser, and start the backup pump laser in a timely manner so that the backup pump laser outputs pump light to compensate the pump output power of the underwater device 100.

[0035] Among them, the detection method of the COTDR (coherent optical time domain reflectometry) device in some embodiments of the present application for detecting a submarine optical cable circuit can include the following.

[0036] The undersea cable circuit detection device emits a detection signal and divides the detection signal input into the first optical amplification unit 150 into a first detection signal and a second detection signal. The two detection signals detect the status of the optical cable circuit connected between the optical amplification unit and the optical amplification unit through different paths.

[0037] After the first detection signal is split, it is directly coupled and looped back to the output end of the second optical amplification unit 160 in a direction different from that of the first optical amplification unit 150 to form a first loopback path, output a first loopback detection signal and return it to the optical cable circuit. After the first detection signal is split, it is directly coupled and looped back to the output end of the second optical amplification unit 160 to form a first loopback path, and output the first loopback detection signal to the upstream or downstream circuit trunk line. The first loopback detection signal is a directly coupled and looped back signal, and the first loopback detection signal power is obtained by measuring the output first loopback detection signal. The second optical amplification unit 160 has a different direction from the first optical amplification unit 150. For example, when detecting downstream, the first optical amplification unit 150 is for downstream transmission, and the second optical amplification unit 160 is for upstream transmission. When the first optical amplification unit 150 is a downstream optical amplification unit, the status of the downstream undersea optical cable circuit can be detected based on the first loopback detection signal power and the second loopback detection signal power. When the first optical amplification unit 150 is an upstream optical functional unit, the status of the upstream undersea optical cable circuit can be detected based on the first loopback detection signal power and the second loopback detection signal power.

[0038] The second detection signal is looped back to the output end of the second optical amplification unit 160 after passing through the first optical amplification unit 150 to form a second loopback path, and outputs a second loopback detection signal. The second detection signal passes through the first optical amplification unit 150 and enters the optical cable circuit. The second detection signal that has passed through the first optical amplification unit 150 is looped back to the output end of the second optical amplification unit 160 to form a second loopback path, and outputs a second loopback detection signal to the upstream or downstream circuit trunk line. Measure the second loopback detection signal to obtain the second loopback detection signal power. The detection device transmits pulsed light, the first loopback detection signal is a pulsed signal, and the power of the second loopback detection signal is determined by the return time and the pulse width. The power of the signal is determined by the return time and the pulse width.

[0039] Detect the status of the submarine optical cable circuit based on the first loopback detection signal power and the second loopback detection signal power.

[0040] Note that the number of backup pump lasers 102 arranged in the underwater device 100 can be selected to be arranged in a certain proportion of the normal pump lasers 101 after being evaluated according to device certainty and system performance.

[0041] In some embodiments, the underwater device 100 includes a plurality of normal pump lasers 101, and the normal pump lasers 101 include a first pump laser and a second pump laser connected to the backup pump laser. The input port of the first optical fiber coupler of the first optical fiber 110 is connected to the first pump laser, and the output port of the first optical fiber coupler of the first optical fiber 110 is connected to the first optical amplification unit 150. The second pump laser and the backup pump laser 102 are respectively connected to the input port of the optical device 130 of the second optical fiber 120, and the output port of the optical device 130 of the second optical fiber 120 is connected to the second optical amplification unit 160. The first pump laser is used to provide pump light to a first optical amplification unit 150 located in a first optical fiber 110, and the second pump laser is used to provide pump light to a second optical amplification unit 160 located in a second optical fiber 120.

[0042] Note that the first optical fiber 110 and the second optical fiber 120 belong to the same optical fiber pair, or the first optical fiber 110 and the second optical fiber 120 belong to different optical fiber pairs. In some embodiments, the first optical fiber 110 can be used to transmit an optical signal to a terrestrial base station at the opposite end, and the second optical fiber 120 can be used to receive an optical signal transmitted from the terrestrial base station at the opposite end.

[0043] In some embodiments, the underwater device 100 includes at least two first pump lasers and two second pump lasers. Each of the first pump lasers provides 50% of the energy to the first optical amplification unit 150, and each second pump laser provides 50% of the energy to the second optical amplification unit 160. Alternatively, the underwater device 100 includes four first pump lasers or four second pump lasers. Each of the first pump lasers provides 25% of the energy to the first optical amplification unit 150, and each second pump laser provides 25% of the energy to the second optical amplification unit 160. That is, the outputs of the four pump lasers are combined via a combining unit and then output to the four optical amplification units of the two fiber pairs. Each pump laser provides one-fourth of the pump energy to each amplifier. At this time, the impact of the failure of one of the pumps on the system optical signal-to-noise ratio is smaller. Among them, only one of the plurality of second pump lasers of the underwater device 100 in this embodiment is connected to the backup pump laser 102. By installing the backup pump laser 102 only on one normal pump laser 101 of the underwater device 100, it is possible to compensate for the reduced pump power due to aging and reduce the cost.

[0044] As shown in FIG. 2, the underwater device 100 adopts single fiber pair 2×2 protection. That is, the outputs of the two normal pump lasers are combined via one coupler and then output to the two optical amplification units of one fiber pair according to a ratio of 50%: Taking the example of outputting to the two optical amplification units of one fiber pair according to a ratio of 50%:50%, based on the two normal pump lasers, one backup pump laser is added, and the backup pump laser and the normal pump laser are optically coupled by a polarization beam combiner (PBC).

[0045] When the underwater device 100 adopts single fiber pair 4×4 protection, in the 4×4 pump optical path used by the underwater device 100, FIG. 3 shows a schematic structural diagram 2 of the underwater device 100. Since the realization principle is similar, the description is omitted.

[0046] Among them, in the 4×8 pump laser used in the underwater device 100, since the realization principle is similar, the description is omitted.

[0047] In some embodiments of the present application, the underwater device 100 provided forms a coupling loopback path for the COTDR backscattered optical signal between the upstream and downstream optical fiber links of the same fiber pair, and is cross-connected by a first optical fiber coupler and a second optical fiber coupler, and pumps light into the optical amplification unit. At the same time, each 2×2 optical fiber coupler in the first stage combines the pump light from two pump lasers and outputs it as two sub-pump lights in the first stage. Each 2×2 optical fiber coupler in the second stage combines two sub-pump lights from different 2×2 optical fiber couplers in the first stage and outputs them as two sub-pump lights in the second stage. Each sub-pump light in the second stage provides energy to one EDFA module, and each pump laser output from each pump laser can provide 25% of the energy for each of the four EDFA modules, and each EDFA module receives 25% of the pump laser energy from the four pump lasers. The first optical fiber coupler and the second optical fiber coupler are cross-connected to each other to form a complete closed loop, have structural symmetry, can be theoretically extended infinitely, and can be applied to an underwater device communication system with any fiber pair of three or more fiber pairs.

[0048] In some embodiments, one backup pump laser is arranged for each of the normal pump lasers. As shown in FIG. 4, the underwater device 100 adopts single fiber pair 2×2 protection, that is, the outputs of two normal pump lasers are combined through one optical fiber coupler and then output to two optical amplification units of one fiber pair according to a ratio of 50%:50%. Taking this as an example, the normal pump laser and the backup pump laser are combined by a polarization beam combiner or an optical switch.

[0049] By arranging backup pump lasers for all the normal pump lasers of all the underwater devices 100 in the entire circuit, the space and granularity for performance adjustment of the entire underwater device communication system are made better.

[0050] In some embodiments, the optical device 130 is a polarization beam combiner or an optical switch. The backup pump laser 102 and the normal pump laser 101 can be optically coupled by a polarization beam combiner (PBC), and the backup pump laser 102 and the normal pump laser 101 can be further controlled using an optical switch.

[0051] The backup pump laser 102 and the normal pump laser 101 are multiplexed by a polarization beam combiner or strobed (selected to be on) via an optical switch. The backup pump laser 102 is always turned off, and when needed, the backup pump laser 102 is activated, and by operating the normal pump laser 101 and the backup pump laser 102 together, the pump output power is made to meet the output requirement.

[0052] In some embodiments, the backup pump laser 102 can select a pump laser that is the same as the output power and reliability level of the normally operating normal pump laser 101. By selecting a device of the same type as the online operating pump, equivalent replacement in the pump failure scenario can be achieved.

[0053] The backup pump laser 102 is only used to compensate for the power reduced due to aging. In some embodiments, the backup pump laser 102 is further the same as the reliability level of the normally operating normal pump laser 101, has a lower output power, and adopts a type with a lower output power than the normally operating pump laser in online operation to reduce costs.

[0054] Since the backup pump laser 102 is activated in the mid- to late-stage of the system, its cumulative operating time is not long, and the requirement for certainty is not high. In some embodiments, the backup pump laser 102 has a lower requirement for the certainty (reliability) level than that of the normal pump laser 101 that operates more normally. For example, an onshore cable-class pump that is not used in a submarine cable repeater can be selected to reduce costs. Also, since device failure is a probabilistic event, by arranging a plurality of devices with ordinary certainty levels, the possibility of some device failures can be probabilistically compensated.

[0055] Note that if the operating current of the pump laser is too large, the probability of pump laser failure increases. Therefore, it is necessary to control the drive current of the backup pump laser 102. In some embodiments, based on the theoretical analysis or actual measurement results of the optimal performance point of the entire submarine cable communication system, some backup pump lasers 102 of the underwater device 100 can be selectively turned on. Among them, the operating current of each backup pump laser 102 is kept constant.

[0056] In some embodiments, based on the theoretical analysis or actual measurement results of the optimal performance point of the entire submarine cable communication system, the drive current of the turned-on backup pump laser 102 can be adjusted to achieve the operation of the underwater device 100 in the optimal state of performance.

[0057] Note that the underwater device 100 in the embodiments of the present application may be a device such as an optical repeater RPT (repeater). In the process of long-distance communication transmission, since the signal is attenuated by the cable, for example, at regular intervals of 50 km, 70 km, 100 km, etc., an optical repeater RPT with a signal relay amplification function is installed in the submarine cable, so that the signal can be transmitted over a long distance. In the construction process of the underwater communication system, the underwater device 100 is usually directly installed on the cable line, wound integrally, and put into the water together with the cable line.

[0058] Add a backup pump laser 102 to the optical repeater to compensate for the reduced output power due to the aging of the normal pump laser, and improve the aging status of the pump laser, so as to match the output power of the optical repeater with the operation requirements, stably maintain the noise figure of the optical repeater, and maintain the stability of the transmission performance.

[0059] As shown in FIG. 5, some embodiments of the present application further provide an underwater device communication system, which includes the underwater device 100 of the above embodiments, and the underwater device communication system includes A first station 200 used to transmit a first data optical signal to the underwater device 100 via the first optical fiber 110, and A second station 300 used to transmit a second data optical signal to the underwater device 100 via the second optical fiber 120, and further includes After receiving the first data optical signal, the underwater device 100 is used to amplify the first data optical signal and then output it to the second station 300, and after receiving the second data optical signal, the underwater device 100 is used to amplify the second data optical signal and then output it to the first station 200. In some embodiments, the first station 200 is further used to transmit a detection optical signal to the underwater device 100 via the first optical fiber 110. The underwater device 100 receives a first reflected optical signal from the optical fiber coupler 140 and transmits the first reflected optical signal in the direction of the first station. The first reflected optical signal is obtained after the amplified detection optical signal undergoes backscattering. The first station 200 further receives the first reflected optical signal and is used to determine whether the normal pump laser 101 has failed or aged based on the first reflected optical signal.

[0060]

[0061] ​Note that the optical amplification unit has an output saturation effect characteristic. When the input optical power of the amplifier reaches the threshold, the input optical power increases or decreases within a certain range, and the output optical power is maintained basically unchanged. The corresponding amplifier gain decreases or increases by basically the same amount as the change in the input optical power. Based on the change amount of the scattered optical power of the optical repeater, it is possible to determine whether the normal pump laser has failed or aged, and it is easy to start the backup pump laser in a timely manner to compensate for the reduced output power due to the aging of the normal pump laser.

[0062] As can be seen from the above technical solutions, some embodiments of the present application provide an underwater device and a communication system. The underwater device includes a first optical fiber, a second optical fiber, a normal pump laser, and at least one backup pump laser. The normal pump laser is used to provide pump light to a first optical amplification unit located in the first optical fiber and a second optical amplification unit located in the second optical fiber. The normal pump laser and the backup pump laser are respectively connected to the input ports of the optical devices of the first optical fiber and / or the second optical fiber. Among them, the optical device is used to optically couple the normal pump laser and the backup pump laser. The backup pump laser is used to compensate the output power when the output power of the normal pump laser is smaller than the target output power. Among them, the compensated output power is the output power lost by the normal pump laser in the aging state. The backup pump laser is arranged to be in an off state until a first command is received, and is started to output pump light when the first command is received. Among them, the first command is a control command transmitted when the output power of the normal pump laser is smaller than the target output power. By installing at least one backup pump laser in the underwater device, the present application can start the backup pump laser to compensate the pump output power of the underwater device when the normal pump laser ages, and improve the service life of the submarine cable optical fiber communication.

[0063] The similar parts among the embodiments provided in this application may be referred to each other. The specific embodiments provided above are only some examples in the general concept of this application and do not limit the protection scope of this application. For those skilled in the art, any other embodiments extended based on the solution means of this application without creative efforts all belong to the protection scope of this application.

Description of Reference Numerals

[0064] 100 - underwater device, 101 - normal pump laser, 102 - backup pump laser, 110 - first optical fiber, 120 - second optical fiber, 130 - optical device, 140 - optical fiber coupler, 150 - first optical amplification unit, 160 - second optical amplification unit, 200 - first station, 300 - second station.

Claims

1. a first optical fiber, a second optical fiber, a normal pump laser, and at least one backup pump laser; the conventional pump laser is used to provide pump light to a first optical amplification unit located in the first optical fiber and a second optical amplification unit located in the second optical fiber; The normal pump laser and the backup pump laser are respectively connected to the input ports of an optical device of the first optical fiber and / or the second optical fiber, wherein the optical device is used for optically coupling the normal pump laser and the backup pump laser; The backup pump laser is used to compensate for the output power of the normal pump laser when the output power of the normal pump laser is smaller than the target output power, and the compensated output power is the output power lost by the normal pump laser in an aging state; The underwater equipment, characterized in that the backup pump laser is in an off state before a first command is received, and is arranged to be activated to output pump light when a first command is received, wherein the first command is a control command sent when the output power of the normal pump laser is less than a target output power.

2. The underwater equipment of claim 1, further comprising: the backup pump laser being configured to be in an off state before a second command is received, and to be activated to output pump light when a second command is received, wherein the second command is a control command sent when the deterioration value of the underwater equipment is greater than a threshold value.

3. the conventional pump laser includes a first pump laser and a second pump laser connected to the backup pump laser; an input port of a first fiber optic coupler of the first optical fiber is connected to the first pump laser, and an output port of the first fiber optic coupler of the first optical fiber is connected to the first optical amplification unit; A second pump laser and the backup pump laser are respectively connected to an input port of the second optical fiber optical device, and an output port of the second optical fiber optical device is connected to the second optical amplification unit; 3. The underwater equipment of claim 2, wherein the first pump laser is used to provide pump light to the first optical amplification unit located in a first optical fiber, and the second pump laser is used to provide pump light to the second optical amplification unit located in the second optical fiber.

4. The underwater device includes at least two first pump lasers and two second pump lasers, each of the first pump lasers providing 50% of the energy to the first optical amplification unit and each of the second pump lasers providing 50% of the energy to the second optical amplification unit; Alternatively, the underwater equipment of claim 3 includes at least four first pump lasers and four second pump lasers, each of the first pump lasers providing 25% of the energy to the first optical amplification unit and each of the second pump lasers providing 25% of the energy to the second optical amplification unit.

5. 5. The underwater device of claim 4, wherein the backup pump laser is connected to only one of the second pump lasers of the underwater device.

6. 4. The underwater device of claim 3, wherein the first optical fiber and the second optical fiber belong to the same optical fiber pair, or the first optical fiber and the second optical fiber belong to different optical fiber pairs.

7. 2. The underwater equipment of claim 1, wherein the optical device is a polarization beam combiner or an optical switch.

8. 3. The underwater equipment according to claim 2, wherein one backup pump laser is disposed for each of the normal pump lasers, and the normal pump laser and the backup pump laser are combined by a polarized beam combiner or an optical switch.

9. The underwater device according to claim 1 , wherein the underwater device is an optical repeater.

10. The underwater device according to any one of claims 1 to 9, a first station used for transmitting a first data optical signal to the underwater device via the first optical fiber; a second station used to transmit a second data optical signal to the underwater device via the second optical fiber; an underwater equipment communication system, characterized in that the underwater equipment is used to receive the first data optical signal, amplify the first data optical signal, and then output it to the second station, and is used to receive the second data optical signal, amplify the second data optical signal, and then output it to the first station.

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