A relay-free transmission system and method for optical fiber hydrophone array

Abstract

The present invention provides a relayless transmission system and method for a fiber optic hydrophone array, wherein the relayless transmission system comprises an optical transmitter, an optical amplifier component, a fiber optic hydrophone array, a remote gain unit, and an optical receiver connected in sequence by transmission optical fibers, wherein the optical amplifier component amplifies the signal light emitted by the optical transmitter and transmits it to the fiber optic hydrophone array, and the signal light output by the fiber optic hydrophone array is amplified by the remote gain unit and transmitted to the optical amplifier component, and then amplified by the optical amplifier component and transmitted to the optical receiver. The relayless transmission system and method of the present invention comprehensively apply doped medium optical amplification technology, fiber distributed Raman amplification technology, and remote optical pumping amplification technology, effectively ensuring the detection capability of the fiber optic hydrophone array for weak signals, and greatly extending the relayless transmission distance of the densely multiplexed fiber optic hydrophone array in the shore-based fixed fiber optic sonar system.

Description

Technical Field

[0001] The present invention relates to the field of underwater detection technology, and in particular to a non-relay transmission system and method for an optical fiber hydrophone array. Background Art

[0002] Sound waves are the only form of energy radiation that can propagate over long distances underwater. Fiber-optic hydrophones are new sensors that use sound waves to detect, locate, and identify underwater targets. They are underwater radars in modern military. As one of the main application forms of fiber-optic hydrophone arrays, the submarine shore-based fixed fiber-optic sonar system is currently the most advanced passive marine detection system. In recent years, with the continuous improvement of ship target noise reduction technology and the continuous improvement of the detection distance and detection accuracy requirements of the sonar system, the scale of the submarine shore-based fixed fiber-optic sonar system has continued to expand, the number of primitives has risen to thousands or even tens of thousands, and the transmission distance has gradually expanded to hundreds or even thousands of kilometers.

[0003] Relay-free transmission is one of the main application forms of long-distance transmission of submarine shore-based fixed fiber optic sonar systems, providing a solution for offshore seabed detection. Among them, the fiber optic hydrophone array usually adopts a time division, wavelength division and space division hybrid multiplexing array mode, but as the shore-based fixed fiber optic sonar system develops towards large-scale and long-distance directions, the array mostly adopts a time division and wavelength division hybrid multiplexing mode, and multiplexes 64-element, 128-element or even 256-element fiber optic hydrophone arrays through a single fiber pair, which greatly reduces the number of optical cable fiber pairs and reduces the system complexity and cost.

[0004] However, the inherent loss of the large-scale densely multiplexed fiber optic hydrophone array itself is large. For example, the inherent loss of a fiber optic hydrophone array with 64 primitives multiplexed in a single fiber pair is usually greater than 20dB, and the more primitives multiplexed in a single fiber pair, the greater the inherent loss of the fiber optic hydrophone array itself. When the fiber transmission distance of the submarine shore-based fixed fiber optic sonar system exceeds 100 kilometers, the optical power loss of the entire transmission system will be greater than 60dB.

[0005] Traditionally, the relayless transmission system based on centralized active erbium-doped fiber amplifiers or distributed fiber Raman amplifiers cannot meet the requirements of relayless transmission of densely multiplexed fiber hydrophone arrays over 100 kilometers offshore. In order to ensure the detection capability of the fiber hydrophone array for weak signals, the analog optical signal transmitted over long distances must be effectively amplified. Therefore, a relayless transmission system is needed that can not only achieve effective amplification of the analog optical signal of the densely multiplexed fiber hydrophone array, but also break through the limitation of the traditional optical amplification method in relayless transmission distance. Summary of the invention

[0006] The present invention aims to solve the problems described above. One object of the present invention is to provide a relay-free transmission system and method for solving any of the above problems. Specifically, the present invention provides a submarine shore-based fixed optical fiber sonar relay-free transmission system and relay-free transmission method that can meet the requirements of an offshore area of ​​more than 100 kilometers.

[0007] According to one aspect of the present invention, there is provided a relayless transmission system for a fiber optic hydrophone array, the relayless transmission system comprising an optical transmitter, an optical amplifier component, a fiber optic hydrophone array, a remote gain unit and an optical receiver connected in sequence by a transmission optical fiber, the remote gain unit and the fiber optic hydrophone array are located at a wet end, the optical transmitter, the optical receiver and the optical amplifier component are located at a dry end; the optical amplifier component amplifies the signal light emitted by the optical transmitter and transmits it to the fiber optic hydrophone array, the signal light output by the fiber optic hydrophone array is amplified by the remote gain unit and transmitted to the optical amplifier component, and then amplified by the optical amplifier component and transmitted to the optical receiver;

[0008] Wherein, the optical amplification component includes a control unit, an optical power amplifier, an optical preamplifier and an associated pump unit, the optical power amplifier is connected to the output optical fiber of the optical transmitter, and is connected to the optical fiber hydrophone array through a transmission optical fiber, so as to increase the optical power of the input fiber; the optical preamplifier is connected to the remote gain unit through a transmission optical fiber, and is connected to the input optical fiber of the optical receiver, so as to improve the sensitivity of the optical receiver; the associated pump unit is optically coupled to the transmission optical fiber between the remote gain unit and the optical preamplifier; the control unit is signal-connected to the optical power amplifier, the optical preamplifier and the associated pump unit, so as to configure the gain and / or output power of the optical power amplifier, the optical preamplifier and the associated pump unit;

[0009] The associated pump unit includes an associated remote pump module, the associated remote pump module is used to provide remote pump light that can reach the remote gain unit, and the remote gain unit amplifies the signal light using the remote pump light from the associated remote pump module.

[0010] Among them, the on-link pump unit also includes an on-link Raman pump module and an on-link combiner. The on-link Raman pump module outputs Raman pump light, which is used to perform co-directional distributed Raman amplification on the remote pump light output by the on-link remote pump module, and perform reverse distributed Raman amplification on the signal light output by the remote gain unit; the on-link combiner is used to combine and output the remote pump light output by the on-link remote pump module and the Raman pump light output by the on-link Raman pump module.

[0011] The optical amplification component further includes a forward Raman pumping unit, which is optically coupled to the transmission optical fiber between the optical power amplifier and the optical fiber hydrophone array, and is used to perform co-directional distributed Raman amplification on the signal light output by the optical power amplifier; the control unit is also used to configure the output power of the forward Raman pumping unit.

[0012] Wherein, the optical amplification component further includes at least one bypass pumping unit, each of which is connected to the remote gain unit via a transmission optical fiber, and the control unit is also used to configure the output power of the bypass pumping unit.

[0013] The bypass pump unit includes a bypass remote pump module, the bypass remote pump module is used to provide additional remote pump light that can reach the remote gain unit, and the remote gain unit further amplifies the signal light using the additional remote pump light from the bypass remote pump module.

[0014] The bypass pump unit further includes a bypass Raman pump module and a bypass combiner, wherein the bypass Raman pump module outputs Raman pump light for co-directional distributed Raman amplification of the additional remote pump light output by the bypass remote pump module; and the bypass combiner is used to combine and output the additional remote pump light output by the bypass remote pump module and the Raman pump light output by the bypass Raman pump module.

[0015] Wherein, the transmission optical fiber used in the relay-free transmission system is a single-mode optical fiber.

[0016] The path-dependent Raman pumping module includes one or more of a first-order Raman pumping laser source group, a second-order Raman pumping laser source group, and a third-order Raman pumping laser source group.

[0017] The forward Raman pumping unit includes one or more of a first-order Raman pumping laser source group, a second-order Raman pumping laser source group, and a third-order Raman pumping laser source group.

[0018] The bypass Raman pump module includes one or more of a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group.

[0019] Wherein, the optical power amplifier is an erbium-doped fiber amplifier or an erbium-doped waveguide optical amplifier, and the optical preamplifier is an erbium-doped fiber amplifier or an erbium-doped waveguide optical amplifier.

[0020] Wherein, the remote gain unit is a doped gain medium unit, and the gain medium in the remote gain unit is an erbium-doped optical fiber or an erbium-doped waveguide device.

[0021] According to another aspect of the present invention, the present invention further provides a relayless transmission method, which is implemented by the relayless transmission system as described above.

[0022] The relay-free transmission system and method of the present invention comprehensively apply doped medium optical amplification technology, fiber distributed Raman amplification technology and remote optical pump amplification technology, use doped medium optical amplifiers as optical power amplifiers and optical preamplifiers to respectively improve the optical power of signal light entering the fiber and the sensitivity of the optical receiver, apply fiber distributed Raman amplification technology to perform distributed Raman amplification of signal light and remote pump light in the transmission fiber, and simultaneously use the gain medium of the remote gain unit in the transmission link to perform remote passive amplification of the signal light, effectively ensuring the detection capability of the fiber optic hydrophone array for weak signals, and greatly extending the relay-free transmission distance of the densely multiplexed fiber optic hydrophone array in the shore-based fixed fiber optic sonar system.

[0023] Other characteristic features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated into the specification and constitute a part of the specification, illustrate embodiments of the present invention and are used together with the description to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, but not all embodiments. For those of ordinary skill in the art, other drawings can be obtained from these drawings without paying creative work.

[0025] Figure 1 A schematic structural diagram of an embodiment of the relay-free transmission system of the present invention is exemplarily shown;

[0026] Figure 2 A schematic structural diagram of a pump-associated unit is shown exemplarily;

[0027] Figure 3 A schematic structural diagram of a second embodiment of the relay-free transmission system of the present invention is exemplarily shown;

[0028] Figure 4 A schematic diagram of the structure of a third embodiment of the relay-free transmission system of the present invention is exemplarily shown;

[0029] Figure 5 A schematic structural diagram of a fourth embodiment of the relay-free transmission system of the present invention is exemplarily shown;

[0030] Figure 6 A schematic diagram showing the structure of a fifth embodiment of the relay-free transmission system of the present invention is exemplarily shown;

[0031] Figure 7 A schematic structural diagram of a bypass pump unit is exemplarily shown;

[0032] Figure 8 The structural diagram of the sixth embodiment of the non-relay transmission system of the present invention is exemplarily shown. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0034] In order to realize the relay-free transmission requirement of more than 100 kilometers of the fiber optic hydrophone array, the present invention provides a relay-free transmission system for the fiber optic hydrophone array, which comprehensively applies the fiber optic distributed Raman amplification technology, the doped medium optical amplification technology and the remote optical pump amplification technology, uses the doped medium optical amplifier as the optical power amplifier and the optical preamplifier to respectively improve the optical power of the signal light entering the fiber and the sensitivity of the optical receiver, applies the fiber optic distributed Raman amplification technology to perform distributed Raman amplification of the signal light and the remote pump light in the transmission fiber, and simultaneously uses the gain medium of the remote gain unit in the transmission link to perform remote passive amplification of the signal light. The comprehensive application of these three technologies minimizes the degradation of the optical signal-to-noise ratio of the system, breaks through the limitation of the traditional optical amplification method on the relay-free transmission distance, and realizes the relay-free transmission requirement of more than 100 kilometers of the submarine shore-based fixed fiber optic sonar system.

[0035] The following describes in detail the relay-free transmission system and method for the optical fiber hydrophone array provided by the present invention in conjunction with the accompanying drawings.

[0036] Figure 1 A schematic structural diagram of a non-relay transmission system for an optical fiber hydrophone array of the present invention is shown. Figure 1As shown, the relay-free transmission system includes an optical transmitter 1, an optical amplifier assembly 2, an optical fiber hydrophone array 3, a remote gain unit 4, and an optical receiver 5 connected in sequence by a transmission optical fiber, wherein the remote gain unit 4 and the optical fiber hydrophone array 3 are located at the wet end, and the optical transmitter 1, the optical receiver 5, and the optical amplifier assembly 2 are located at the dry end. After the signal light emitted by the optical transmitter 1 is amplified by the optical amplifier assembly 2, it passes through the transmission optical fiber 10a in front of the optical fiber hydrophone array 3, the optical fiber hydrophone array 3, and the transmission optical fiber 10b between the optical fiber hydrophone array 3 and the remote gain unit 4 in sequence. The signal light reaching the remote gain unit 4 is amplified again, and then enters the transmission optical fiber 10c. The signal light enters the optical amplifier assembly 2 through the transmission optical fiber 10c for further amplification, and finally enters the optical receiver 5 to be received.

[0037] Among them, the remote gain unit 4 is a doped gain medium unit, and its core component is a doped gain medium device, which can amplify the signal light under the action of remote pump light. The doped gain medium in the remote gain unit 4 is a passive medium, which can be a section of erbium-doped optical fiber, or an erbium-doped waveguide or other doped gain medium. The remote gain unit 4 is also a passive module, does not require power supply, and can usually be installed in a submarine cable splicing box or an array cable splicing box.

[0038] exist Figure 1 In the illustrated embodiment, the optical amplification component 2 includes a control unit 21, an optical power amplifier 22, an optical preamplifier 23 and an associated pump unit 24. The optical power amplifier 22 is connected to the output optical fiber of the optical transmitter 1, and is connected to the optical fiber hydrophone array 3 through the transmission optical fiber 10a; the optical preamplifier 23 is connected to the remote gain unit 4 through the transmission optical fiber 10c, and is connected to the input optical fiber of the optical receiver 5; the associated pump unit 24 is optically coupled to the transmission optical fiber 10c between the remote gain unit 4 and the optical preamplifier 23, that is, the remote pump light emitted by the associated pump unit 24 is coupled into the transmission optical fiber 10c through the wavelength division multiplexing device; the control unit 21 is signal-connected to the optical power amplifier 22, the optical preamplifier 23, and the associated pump unit 24, and is used to configure the gain and / or output power and other parameters of the optical power amplifier 22, the optical preamplifier 23, and the associated pump unit 24.

[0039] The optical power amplifier 22 is used to increase the optical power of the input fiber, and the optical preamplifier 23 is used to increase the sensitivity of the optical receiver 5. In the present invention, the optical power amplifier 22 can be a conventional erbium-doped fiber amplifier, or an erbium-doped waveguide optical amplifier or other types of doped medium optical amplifiers; correspondingly, the optical preamplifier 23 can be a conventional erbium-doped fiber amplifier, or an erbium-doped waveguide optical amplifier or other types of doped medium optical amplifiers.

[0040] The associated pump unit 24 includes an associated remote pump module 241, which is used to provide remote pump light that can reach the remote gain unit 4. The remote gain unit 4 amplifies the optical signal using the remote pump light from the associated remote gain module 24. Specifically, the associated remote pump module 241 is used to provide remote pump light, which is transmitted in the transmission optical fiber 10c in the opposite direction to the signal light and reaches the remote gain unit 4. The remote gain unit 4 amplifies the signal light using the interaction between its gain medium and the remote pump light and the signal light.

[0041] Since the signal light of 1550nm band can increase the optical power with the help of optical amplifier, and the inherent attenuation per unit distance in standard single-mode optical fiber is lower, the signal light of 1550nm band is mostly used in long-distance signal transmission. For example, for erbium-doped gain medium, to amplify the signal light of 1550nm band, the pump light is generally 980nm or 1480nm band, because the transmission loss of the pump light of 1480nm band in the transmission optical fiber is relatively smaller, therefore, the wavelength of the pump laser source group of the remote pump module 241 is usually selected as 1480nm band.

[0042] During operation, the signal light emitted by the optical transmitter 1 is amplified by the optical power amplifier 22, and then passes through the transmission optical fiber 10a, the optical fiber hydrophone array 3 and the transmission optical fiber 10b in sequence, and reaches the remote gain unit 4 to be amplified again, and then enters the transmission optical fiber 10c; it is transmitted to the optical preamplifier 23 through the transmission optical fiber 10c for further amplification, and finally enters the optical receiver 5 to be received. The traditional long-distance non-relay transmission system is mainly limited by the optical power and the optical signal-to-noise ratio and is difficult to achieve the expected transmission distance. The optical power can be well solved by the optical amplifier, but the optical signal-to-noise ratio is difficult to meet expectations. The present invention adopts remote optical pumping amplification technology to ensure that the signal light power is amplified when it is relatively high, reduce the degradation of the optical signal-to-noise ratio due to long-distance transmission, and greatly extend the non-relay transmission distance of the optical fiber hydrophone array in the shore-based fixed optical fiber sonar system.

[0043] Figure 2 A schematic structural diagram of a specific embodiment of the associated pump unit 24 in the present invention is shown. In this embodiment, the associated pump unit 24 includes an associated remote pump module 241, an associated Raman pump module 242 and an associated combiner 243.

[0044] comprehensive Figure 1 and Figure 2As shown, the accompanying remote pump module 241 is used to provide remote pump light that can reach the remote gain module 4. The remote pump light is transmitted in the transmission optical fiber 10c in the opposite direction to the signal light. When it reaches the remote gain module 4, the signal light is amplified by the interaction between the gain medium, the remote pump light and the signal light. The accompanying Raman pump module 242 is used to provide Raman pump light. The Raman pump light is transmitted in the transmission optical fiber 10c in the same direction as the remote pump light output by the accompanying remote pump module 241, that is, the transmission direction of the Raman pump light in the transmission optical fiber 10c is opposite to the transmission direction of the signal light output by the remote gain module 4. The Raman pump light emitted by the accompanying Raman pump module 242 is used to perform co-directional distributed Raman amplification on the remote pump light output by the accompanying remote pump module 241, and to perform reverse distributed Raman amplification on the signal light output by the remote gain unit 4. The associated combiner 243 is used to combine and output the remote pump light output by the associated remote pump module 241 and the Raman pump light output by the associated Raman pump module 242 .

[0045] Exemplarily, the accompanying Raman pump module 242 includes one or more of a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group, for example, it may include only a first-order Raman pump laser source group, or may include a first-order Raman pump laser source group and a second-order Raman pump laser source group, or may include a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group. Among them, the wavelength of the first-order Raman pump laser source group is 14xxnm, the wavelength of the second-order Raman pump laser source group is 13xxnm, and the wavelength of the third-order Raman pump laser source group is 12xxnm.

[0046] For fiber distributed Raman amplification, its gain spectrum is a continuous spectrum, the peak gain wavelength is about 100nm longer than the provided Raman pump wavelength, and the gain bandwidth is about 300nm. To perform distributed Raman amplification on the remote pump light in the 1480nm band and the signal light in the 1550nm band, the Raman pump light wavelength is selected as 14xxnm, which is a first-order Raman pump laser source group; the wavelength of the second-order Raman pump laser source group is selected as 13xxnm, and the 14xxnm Raman pump light of the first-order Raman pump laser source group is distributed Raman amplified; the wavelength of the third-order Raman pump laser source group is selected as 12xxnm, and the 13xxnm Raman pump light of the second-order Raman pump laser source group is distributed Raman amplified.

[0047] Figure 3 A schematic diagram showing the structure of a second embodiment of the non-relay transmission system of the present invention is shown. Figure 1 Compared with the embodiment shown in FIG. 1 , in this embodiment, the optical amplification component 2 further includes a forward Raman pump unit 25. Figure 2 The structure of the accompanying pump unit 24 is similar to Figure 3 The relayless transmission system shown is integrated, that is, in the relayless transmission system in which the associated pump unit 24 includes an associated remote pump module 241, an associated Raman pump module 242 and an associated combiner 243, a forward Raman pump unit 25 is further provided.

[0048] Specifically, the forward Raman pump unit 25 is optically coupled to the transmission optical fiber 10a between the optical power amplifier 22 and the optical fiber hydrophone array 3, that is, the Raman pump light emitted by the forward Raman pump unit 25 is coupled into the transmission optical fiber 10a via a wavelength division multiplexing device, and is used to perform co-directional distributed Raman amplification on the signal light output by the optical power amplifier 22. The forward Raman pump unit 25, the control unit 21, the optical power amplifier 22, the optical preamplifier 23, and the associated pump unit 24 are all located at the dry end, and the forward Raman pump unit 25 is also signal-connected to the control unit 21, and the control unit 21 configures the parameters such as the output power of the pump laser source group of the forward Raman pump unit 25.

[0049] Exemplarily, the forward Raman pumping unit 25 includes one or more of a first-order Raman pumping laser source group, a second-order Raman pumping laser source group, and a third-order Raman pumping laser source group. For example, it may include only a first-order Raman pumping laser source group, or may include a first-order Raman pumping laser source group and a second-order Raman pumping laser source group, or may include a first-order Raman pumping laser source group, a second-order Raman pumping laser source group, and a third-order Raman pumping laser source group. Among them, the wavelength of the first-order Raman pumping laser source group is 14xxnm, the wavelength of the second-order Raman pumping laser source group is 13xxnm, and the wavelength of the third-order Raman pumping laser source group is 12xxnm. In an optional embodiment, the forward Raman pumping unit 25 includes a first-order Raman pumping laser source group, which emits Raman pumping light in the 14xxnm band.

[0050] Specifically, the Raman pump light emitted by the forward Raman pump unit 25 is coupled into the transmission optical fiber 10a between the optical power amplifier 22 and the optical fiber hydrophone array 3, and is transmitted in the same direction as the signal light. The signal light interacts with the 14xxnm Raman pump light in the transmission optical fiber 10a, and distributed Raman amplification occurs. By adopting the technical solution of this embodiment, the output power of the optical power amplifier 22 can be reduced, that is, the input optical power can be reduced. Since the size of the input optical power is closely related to the nonlinear effect of the optical fiber, reducing the input optical power can effectively reduce the influence of the nonlinear effect of the optical fiber on the signal light, improve the quality of the signal light, and provide support for transmitting the signal light over a longer distance.

[0051] In the relay-free transmission system of the present invention, the optical amplification component 2 may further include at least one bypass pump unit 26 signal-connected to the control unit 21. Figure 4 FIG. 4 is a schematic diagram showing the structure of a third embodiment of the relay-free transmission system of the present invention. Figure 5 FIG. 4 is a schematic diagram showing the structure of a fourth embodiment of the relay-free transmission system. Figure 6 FIG. 5 shows a schematic diagram of the structure of the fifth embodiment of the non-relay transmission system. Figure 4 In the embodiment shown, Figure 1 Based on the structure of the non-relay transmission system of the embodiment shown, two bypass pump units 26 are provided; Figure 5 The embodiment shown is in Figure 3 On the basis of the illustrated embodiment, a bypass pump unit 26 is provided; Figure 6 The embodiment shown is in Figure 3 In the optical amplifier assembly 2 of the illustrated embodiment, two bypass pump units 26 are added to form a relay-free transmission system.

[0052] comprehensive Figure 4-Figure 6 As shown, each bypass pump unit 26 is located at the dry end and is connected to the remote gain unit 4 through the transmission optical fiber 10d, that is, the multiple bypass pump units 26 are in parallel. Accordingly, the control unit 21 is also used to configure the output power and other parameters of the pump laser source group of the bypass pump unit 26.

[0053] In an optional specific embodiment, the bypass pump unit 26 includes a bypass remote pump module 261, which is used to provide additional remote pump light that can reach the remote gain unit 4, such as additional remote pump light in the 1480nm band, and the remote gain unit 4 further amplifies the signal light using the additional remote pump light from the bypass remote pump module 261. The additional remote pump light provided by the bypass remote pump module 261 is used to increase the gain of the signal light in the remote gain unit 4, providing support for transmitting the signal light over a longer distance.

[0054] Figure 7 A schematic diagram of a specific embodiment of the bypass pump unit 26 is shown. In this embodiment, the bypass pump unit 26 includes a bypass remote pump module 261, a bypass Raman pump module 262 and a bypass combiner 263. The bypass Raman pump module 262 outputs Raman pump light, which is used to perform co-directional distributed Raman amplification on the additional remote pump light output by the bypass remote pump module 261 in the transmission optical fiber 10d, so as to further increase the remote pump light power in the 1480nm band reaching the remote gain unit 4; the bypass combiner 263 is used to combine and output the additional remote pump light output by the bypass remote pump module 261 and the Raman pump light output by the bypass Raman pump module 262.

[0055] Exemplarily, the bypass Raman pump module 262 includes one or more of a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group. For example, it may include only a first-order Raman pump laser source group, or a first-order Raman pump laser source group and a second-order Raman pump laser source group, or a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group. The wavelength of the first-order Raman pump laser source group is 14xxnm, the wavelength of the second-order Raman pump laser source group is 13xxnm, and the wavelength of the third-order Raman pump laser source group is 12xxnm. Return to reference Figure 4 and Figure 6 In the embodiment shown, if the bypass pump unit 26 in the embodiment adopts Figure 7 The structure shown can further increase the pump light power in the 1480nm band reaching the remote gain unit 4, that is, further increase the gain of the signal light in the remote gain unit 4, improve the signal light power level, and further extend the transmission distance of the signal light.

[0056] Figure 8 The structure diagram of the sixth specific embodiment of the relayless transmission system of the present invention is shown. In this embodiment, the optical amplification component 2 of the relayless transmission system includes an associated pump unit 24, a forward Raman pump unit 25, and a bypass pump unit 26. At this time, the associated pump unit 24 may include an associated remote pump module 241, an associated Raman pump module 242, and an associated combiner 243 as shown in the figure, or may only include the associated remote pump module 241; the bypass pump unit 26 may include a bypass remote pump module 261, a bypass Raman pump module 262, and a bypass combiner 263, or may only include the bypass remote pump module 261.

[0057] It should be noted that the transmission optical fiber used in the non-relay transmission system of the present invention is a single-mode optical fiber, for example, it can be a G.652 or G.654 single-mode optical fiber.

[0058] For example, if the length of the transmission optical fiber 10a between the optical power amplifier 22 and the optical fiber hydrophone array 3 is L1, the length of the transmission optical fiber 10b between the optical fiber hydrophone array 3 and the remote gain unit 4 is L2, the length of the transmission optical fiber 10c between the remote gain unit 4 and the optical preamplifier 23 is L3, and the length of the transmission optical fiber 10d between each bypass pump unit 26 and the remote gain unit 4 is L4, then the following relationship is satisfied:

[0059] L1=L2+L3, and L2≥0; L4=L3.

[0060] In accordance with the above-mentioned non-relay transmission system for the optical fiber hydrophone array, the present invention further provides a non-relay transmission method for the optical fiber hydrophone array, which is implemented by the above-mentioned non-relay transmission system. In the non-relay transmission method, the optical fiber distributed Raman amplification technology, the doped medium optical amplification technology and the remote pump optical amplification technology are comprehensively applied, and specifically include the following steps:

[0061] The optical power amplifier 22 amplifies the power of the signal light emitted by the optical transmitter 1 and then enters the transmission optical fiber 10a for transmission;

[0062] The forward Raman pump unit 25 outputs Raman pump light to the transmission optical fiber 10a, and performs co-directional distributed Raman amplification on the signal light in the transmission optical fiber 10a; the signal light after the co-directional distributed Raman amplification is transmitted to the remote gain unit 4 through the optical fiber hydrophone array 3;

[0063] The remote gain unit 4 utilizes the interaction between its gain medium and the remote pump light emitted by the accompanying pump unit 24 or the remote pump light emitted by the accompanying pump unit 24 and at least one bypass pump unit 26 and the signal light output by the optical fiber hydrophone array 3 to amplify the signal light, wherein the transmission direction of the remote pump light is opposite to that of the signal light;

[0064] The Raman pump light emitted by the accompanying Raman pump module 242 in the accompanying pump unit 24 performs distributed Raman amplification in the same direction on the remote pump light emitted by the accompanying remote pump module 241 in the transmission optical fiber 10c, and performs distributed Raman amplification in the opposite direction on the signal light output by the remote gain unit 4;

[0065] If the bypass pump module 26 is provided, the bypass Raman pump module 262 in each bypass pump module 26 performs co-directional distributed Raman amplification on the additional remote pump light emitted by the bypass remote pump module 261 in the respective transmission optical fiber 10d;

[0066] The optical preamplifier 23 re-amplifies the signal light transmitted from the transmission optical fiber 10 c and transmits the signal light to the optical receiver 5 .

[0067] The contents described above may be implemented individually or in combination in various ways, and these variations are all within the protection scope of the present invention.

[0068] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A relay-free transmission system for a fiber optic hydrophone array, characterized in that: The relay-free transmission system comprises an optical transmitter (1), an optical amplifier component (2), an optical fiber hydrophone array (3), a remote gain unit (4) and an optical receiver (5) connected in sequence by transmission optical fibers, wherein the remote gain unit (4) and the optical fiber hydrophone array (3) are located at a wet end, and the optical transmitter (1), the optical receiver (5) and the optical amplifier component (2) are located at a dry end; the optical amplifier component (2) amplifies the signal light emitted by the optical transmitter (1) and transmits it to the optical fiber hydrophone array (3); the signal light output by the optical fiber hydrophone array (3) is amplified by the remote gain unit (4) and transmitted to the optical amplifier component (2), and then amplified by the optical amplifier component (2) and transmitted to the optical receiver (5); The optical amplification component (2) comprises a control unit (21), an optical power amplifier (22), an optical preamplifier (23) and an associated pump unit (24); the optical power amplifier (22) is connected to the output optical fiber of the optical transmitter (1), and is connected to the optical fiber hydrophone array (3) through a transmission optical fiber, so as to increase the optical power of the input fiber; the optical preamplifier (23) is connected to the remote gain unit (4) through a transmission optical fiber, and is connected to the input optical fiber of the optical receiver (5), so as to increase the sensitivity of the optical receiver (5); the associated pump unit (24) is optically coupled to the transmission optical fiber between the remote gain unit (4) and the optical preamplifier (23); the control unit (21) is signal-connected to the optical power amplifier (22), the optical preamplifier (23) and the associated pump unit (24), so as to configure the gain and / or output power of the optical power amplifier (22), the optical preamplifier (23) and the associated pump unit (24); The on-link pump unit (24) comprises an on-link remote pump module (241), wherein the on-link remote pump module (241) is used to provide remote pump light that can reach the remote gain unit (4), and the remote gain unit (4) amplifies the signal light using the remote pump light from the on-link remote pump module (241); The on-path pump unit (24) further comprises an on-path Raman pump module (242) and an on-path combiner (243); the on-path Raman pump module (242) outputs Raman pump light for performing co-directional distributed Raman amplification on the remote pump light output by the on-path remote pump module (241), and performing reverse distributed Raman amplification on the signal light output by the remote gain unit (4); the on-path combiner (243) is used to combine and output the remote pump light output by the on-path remote pump module (241) and the Raman pump light output by the on-path Raman pump module (242); The optical power amplifier (22) is an erbium-doped optical fiber amplifier or an erbium-doped waveguide optical amplifier, and the optical preamplifier (23) is an erbium-doped optical fiber amplifier or an erbium-doped waveguide optical amplifier.

2. The non-relay transmission system according to claim 1, characterized in that: The optical amplification component (2) further comprises a forward Raman pumping unit (25), the forward Raman pumping unit (25) being optically coupled to the transmission optical fiber between the optical power amplifier (22) and the optical fiber hydrophone array (3), and being used for performing co-directional distributed Raman amplification on the signal light output by the optical power amplifier (22); The control unit (21) is also used to configure the output power of the forward Raman pump unit (25).

3. The non-relay transmission system according to claim 1, characterized in that: The optical amplification component (2) further comprises at least one bypass pumping unit (26), each of the bypass pumping units (26) being connected to the remote gain unit (4) via a transmission optical fiber, and the control unit (21) is further used to configure the output power of the bypass pumping unit (26).

4. The non-relay transmission system according to claim 3, characterized in that: The bypass pump unit (26) comprises a bypass remote pump module (261), wherein the bypass remote pump module (261) is used to provide additional remote pump light that can reach the remote gain unit (4), and the remote gain unit (4) amplifies the signal light using the additional remote pump light from the bypass remote pump module (261).

5. The non-relay transmission system according to claim 4, characterized in that: The bypass pump unit (26) further comprises a bypass Raman pump module (262) and a bypass combiner (263), wherein the bypass Raman pump module (262) outputs Raman pump light for co-directional distributed Raman amplification of the additional remote pump light output by the bypass remote pump module (261); and the bypass combiner (263) is used to combine and output the additional remote pump light output by the bypass remote pump module (261) and the Raman pump light output by the bypass Raman pump module (262).

6. The non-relay transmission system according to claim 1, characterized in that: The transmission optical fiber used in the non-relay transmission system is a single-mode optical fiber.

7. The non-relay transmission system according to claim 1, characterized in that: The on-channel Raman pump module (242) includes one or more of a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group.

8. The non-relay transmission system according to claim 2, characterized in that: The forward Raman pumping unit (25) comprises one or more of a first-order Raman pumping laser source group, a second-order Raman pumping laser source group, and a third-order Raman pumping laser source group.

9. The non-relay transmission system according to claim 5, characterized in that: The bypass Raman pump module (262) includes one or more of a first-order Raman pump laser source group, a second-order Raman pump laser source group, and a third-order Raman pump laser source group.

10. The non-relay transmission system according to claim 1, characterized in that: The remote gain unit (4) is a doped gain medium unit, and the gain medium in the remote gain unit (4) is an erbium-doped optical fiber or an erbium-doped waveguide device.

11. A non-relay transmission method, characterized in that: The non-relay transmission method is implemented by the non-relay transmission system according to any one of claims 1-10.

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