Raman transmission system

Abstract

The invention relates to the technical field of optical communication, and provides a Raman transmission system which comprises a first performance convergence unit, a first optical path subunit, a second optical path subunit and a second performance convergence unit. According to the method, the optimal backward Raman pumping power value is determined by reducing the output power of the power amplifier and the pumping power value of the forward Raman amplifier and comparing service performance parameters of a receiving end; and then the output power of the power amplifier and the pumping power of the forward Raman amplifier are respectively adjusted according to a preset rule until the service performance parameters are not degraded any more, and the optimal output power of the power amplifier and the optimal pumping power of the forward Raman amplifier are obtained. According to the embodiment of the invention, by adjusting the power of different amplifiers and simulating different states of transmission lines, the optimal power value of each amplifier is accurately obtained, the optimal transmission performance of the system is determined, the problem that the Raman transmission system engineering is debugged by experience when being opened can be solved, and the opening time of the Raman system is greatly saved.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and more particularly to a Raman transmission system. Background Technology

[0002] With the development of science and technology and communication technology, ultra-long-distance repeaterless transmission systems are increasingly used in ocean communication, island communication, and power communication. Raman transmission technology is one of the most common optical amplification technologies in repeaterless communication systems. Because Raman transmission technology can greatly improve the repeaterless transmission distance, it is widely used in ultra-long-distance repeaterless transmission systems. However, due to the high output power and strong gain of Raman transmission systems, nonlinear effects are easily induced in optical fibers, resulting in transmission costs. This significantly affects the system's performance and stability. Therefore, in Raman transmission systems, it is necessary not only to ensure a long transmission distance (i.e., high gain, output power, etc.) but also to minimize nonlinear costs. This makes the selection and commissioning process of Raman transmission systems very difficult, and choosing the appropriate power is particularly important during the commissioning process. Furthermore, as the Raman transmission system ages, the optical fiber will age, and the Raman effect will change, requiring adjustment of the system's optimal power value. Currently, the commissioning of Raman transmission systems is mainly carried out manually by engineering and maintenance personnel. The power setting values ​​rely on experience and cannot provide accurate or optimal power values. Furthermore, since the power values ​​of each Raman transmission system are different, the commissioning and debugging of Raman transmission systems is very difficult. Summary of the Invention

[0003] In view of the above problems, it is necessary to propose a Raman transmission system to solve or partially solve the above problems. The technical solution proposed by the present invention is as follows:

[0004] A Raman transmission system is provided, connected between a near-end transmission device 30 and a far-end transmission device 30'. The Raman transmission system includes: a first performance convergence unit 10, a first optical path subunit 20, a second optical path subunit 20', and a second performance convergence unit 10', wherein:

[0005] The first performance convergence unit 10 is used to connect to the receiving end of the near-end transmission device 30, and the first optical path subunit 20 is used to connect to the transmitting end of the far-end transmission device 30'; the second performance convergence unit 10' is used to connect to the transmitting end of the near-end transmission device 30, and the second optical path subunit 20' is used to connect to the receiving end of the far-end transmission device 30'; both the first optical path subunit 20 and the second optical path subunit 20' include at least a power amplifier 21, a forward Raman amplifier 22, and a backward Raman amplifier 24;

[0006] The first performance convergence unit 10 is configured to acquire the service performance parameters of the receiving end of the near-end transmission device 30 in real time, and notify the second performance convergence unit 10' to reduce the initial value of the output power of the power amplifier 21 of the first optical path subunit 20 and the pump power of the forward Raman amplifier 22 until the service performance parameters reach a preset threshold; it is also configured to adjust the pump power of the backward Raman amplifier 24 of the first optical path subunit 20 after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and take the backward Raman pump power at this time as the first power value; it is also configured to notify the second performance convergence unit 10' to restore the pump power and power amplification of the forward Raman amplifier 22 after the backward Raman amplifier 24 is at the first power value. The output power of the amplifier 21 is adjusted such that the pump power of the forward Raman amplifier 22 is restored to its initial value, and the output power of the power amplifier 21 is restored to its initial value. Then, the pump power of the backward Raman amplifier 24 is reduced until the service performance parameters reach a preset threshold. The pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 at this time are taken as the second power value. The amplifier 24 is also used to notify the second performance convergence unit 10' to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules when the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are the second power value, until the service performance parameters no longer deteriorate. Then, the pump power of the backward Raman amplifier 24 is restored to the first power value.

[0007] The second performance convergence unit 10' is used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the first optical path subunit 20 according to the notification content sent by the first performance convergence unit 10.

[0008] Furthermore, the first performance convergence unit 10 is also used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the second optical path subunit 20' according to the notification content sent by the second performance convergence unit 10';

[0009] The second performance convergence unit 10' is further configured to acquire the service performance parameters of the receiving end of the remote transmission device 30' in real time, and notify the first performance convergence unit 10 to reduce the initial value of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 of the second optical path subunit 20' until the service performance parameters reach a preset threshold; it is also configured to adjust the pump power of the backward Raman amplifier 24 of the second optical path subunit 20' after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and take the backward Raman pump power at this time as the first power value; it is also configured to notify the first performance convergence unit 10 to restore the pump power and power of the forward Raman amplifier 22 after the backward Raman amplifier 24 is at the first power value. The output power of the power amplifier 21 is reduced, the pump power of the forward Raman amplifier 22 is restored to its initial value, and the output power of the power amplifier 21 is reduced to its initial value. Then, the pump power of the backward Raman amplifier 24 is reduced until the service performance parameters reach a preset threshold. The pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 at this time are taken as the second power value. It is also used to notify the first performance convergence unit 10 to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules when the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are the second power value, until the service performance parameters no longer deteriorate. Then, the pump power of the backward Raman amplifier 24 is restored to the first power value.

[0010] Furthermore, the second performance convergence unit 10' is used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the first optical path subunit 20 according to the notification content sent by the first performance convergence unit 10, including:

[0011] After receiving a notification to reduce the initial value of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 of the first optical path subunit 20, the second performance convergence unit 10' reduces the output power of the power amplifier 21 by a preset first step length and reduces the pump power of the forward Raman amplifier 22 by a preset second step length until the service performance parameters of the receiving end of the near-end transmission device 30 reach a preset threshold.

[0012] The first performance convergence unit 10 is further configured to, after the service performance parameter reaches a preset threshold, adjust the pump power of the backward Raman amplifier 24 of the first optical path subunit 20 until the service performance parameter no longer deteriorates, and take the backward Raman pump power at this time as the first power value, including:

[0013] Increase or decrease the pump power of the backward Raman amplifier 24 according to the preset third step length, and record the service performance parameters after each adjustment. Take the backward Raman pump power corresponding to the best service performance parameters as the first power value.

[0014] The second performance convergence unit 10' is notified to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules until the service performance parameters no longer deteriorate, and then restore the pump power of the backward Raman amplifier 24 to the first power value.

[0015] Furthermore, after receiving a notification from the first performance convergence unit 10 that the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 are adjusted according to preset rules, the second performance convergence unit 10' is also configured to:

[0016] Iterate through all combinations of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22, and record all service performance parameters corresponding to different combinations;

[0017] Find the optimal service performance parameters, and use the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 corresponding to these optimal service performance parameters as the second power value;

[0018] Adjust the output power of power amplifier 21 and the pump power of forward Raman amplifier 22 to the second power.

[0019] Furthermore, the second performance convergence unit 10' traverses all combinations of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22, recording all service performance parameters corresponding to different combinations, including:

[0020] The output power of the power amplifier 21 is reduced by a preset first step length. While keeping the output power unchanged, the forward pump power is adjusted multiple times by a preset second step length. The service performance parameters corresponding to different pump powers are recorded respectively, and the optimal service performance parameters corresponding to the current power amplifier output power are determined.

[0021] Repeat the above steps multiple times to continuously reduce the output power of the power amplifier 21 by the preset first step length and adjust the forward pump power multiple times by the preset second step length, and finally obtain all service performance parameters corresponding to the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 for different combinations.

[0022] Furthermore, the first performance convergence unit 10 includes at least a first multiplexer / demultiplexer 11, an optical monitoring channel 12, a second multiplexer / demultiplexer 11', and a controller 13, wherein:

[0023] The first input terminal of the first multiplexer / demultiplexer 11 is used to connect to the transmitting end of the near-end transmission device 30, the second input terminal is used to connect to the transmitting end of the optical monitoring channel 12, and the output terminal of the first multiplexer / demultiplexer 11 is used to connect to the first optical path subunit 20.

[0024] The receiving end of the optical monitoring channel 12 is connected to the first output end of the second multiplexer / demultiplexer 11';

[0025] The second output terminal of the second multiplexer / demultiplexer 11' is used to connect to the receiving end of the near-end transmission device 30, and the input terminal of the second multiplexer / demultiplexer 11' is used to connect to the output terminal of the first optical path subunit 20.

[0026] The controller 13 is connected to the control terminal of the optical monitoring channel 12, the second optical path sub-unit 20', and the near-end transmission device 30, respectively.

[0027] Furthermore, the first performance convergence unit 10 also includes an optical attenuator 14, the input of which is connected to the transmitter of the near-end transmission device 30, and the output is connected to the first input of the first multiplexer / demultiplexer 11.

[0028] Furthermore, after adjusting the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to preset rules until the service performance parameters no longer deteriorate, and restoring the pump power of the backward Raman amplifier 24 to the first power value, the second performance convergence unit 10' is also used to increase the attenuation value of the optical attenuator 14 until the service performance parameters of the near-end transmission device 30 receiver reach a preset threshold, and the increased value of the attenuator is recorded as the current margin of the Raman transmission system.

[0029] Furthermore, the service performance parameter is the FEC error rate or quality factor before correction.

[0030] Furthermore, both the first optical path subunit 20 and the second optical path subunit 20' further include a transmission optical fiber 23 and a preamplifier 25; wherein, the power amplifier 21, the forward Raman amplifier 22, the transmission optical fiber 23, the backward Raman amplifier 24 and the preamplifier 25 are connected in sequence.

[0031] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:

[0032] The Raman transmission system provided in this embodiment of the invention first eliminates the influence of the preamplifier on nonlinear effects. It determines the optimal power value of the backward Raman pump by reducing the output power of the power amplifier and the pump power value of the forward Raman amplifier and comparing it with the service performance parameters at the receiving end. Then, it restores the pump power of the forward Raman amplifier and the output power of the power amplifier to their initial values, and then reduces the pump power of the backward Raman amplifier until the service performance parameters reach a preset threshold. Then, it adjusts the output power of the power amplifier and the pump power of the forward Raman amplifier according to preset rules until the service performance parameters no longer deteriorate, thus obtaining the optimal output power of the power amplifier and the pump power of the forward Raman amplifier. Finally, it restores the pump power of the backward Raman amplifier to its optimal power value.

[0033] This invention, by adjusting the power of different amplifiers, simulates different states of the transmission line, accurately obtains the optimal power value of each amplifier, determines the optimal transmission performance of the system, solves the problem of relying on experience for commissioning of Raman transmission system projects, and greatly saves the commissioning time of Raman systems. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a Raman transmission system provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the working process of a Raman transmission system provided in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram illustrating the relationship between the pre-correction bit error rate and amplifier power provided in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of a process for obtaining the optimal forward Raman amplifier pump power and the optimal power amplifier output power according to an embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram of another Raman transmission system provided in an embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0042] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0043] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0044] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling," "wireless connection," etc. The embodiments disclosed herein are not necessarily limited to the scope of this invention.

[0045] In the description of this invention, the expression “A and / or B” (where A and B are used to formally represent specific features) will be used. The corresponding expression includes the following three combinations: only A, only B, and a combination of A and B.

[0046] As used in this invention, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from a particular value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0047] The nonlinear cost of Raman transmission systems is a key factor determining system performance. Therefore, the applicant first investigated the main causes of this nonlinear cost. The applicant found that excessively high input optical power can lead to nonlinear effects such as stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). SRS is generated by inelastic collisions between photons and thermally moving molecules in the fiber and exhibits a significant threshold. When the signal power exceeds a certain threshold, the signal energy rapidly shifts to the Raman scattered light. Due to its high threshold power, SBS generally precedes SRS. SBS is the most likely nonlinear effect to occur in optical fiber communication because of its threshold power P. th Lower, when the input fiber power Pin exceeds the SBS threshold power P th At this time, due to the effect of the signal light, a large amount of backscattered Stokes light is generated in the optical fiber, and the power of the scattered Stokes light increases sharply with the increase of distance, thus generating serious noise in the system. The threshold power P of SBS in the optical fiber th It can be represented as:

[0048]

[0049] Where C is a constant coefficient; γ is the gain coefficient of SBS, which is related to wavelength and fiber core material; K is the polarization dependence factor (K=1 for polarization-maintaining fiber, K=2 for ordinary single-mode fiber); A eff λ is the effective area of ​​the optical fiber; α is the loss coefficient of the optical fiber; L is the length of the optical fiber; ΔνB is the stimulated Brillouin band width, which is related to the fiber type and wavelength; ΔνS is the spectral width of the modulation signal. When the optical signal and the optical fiber are constant, the threshold power P of the SBS is... th It is also certain that, under normal circumstances, the threshold power P of SBS is calculated. th The output signal strength is 7dBm to 8dBm, which is easily achievable for power amplifiers (power amplifiers typically output around 15dBm). Therefore, power amplifiers are prone to introducing nonlinear effects. However, for preamplifiers, due to limitations in the receiver power (which could burn out the receiver's laser), the output signal is generally less than zero. Furthermore, the signal from the receiver to the receiver does not travel long distances via fiber optic cable. Therefore, preamplifiers do not introduce nonlinear effects.

[0050] For Raman amplifiers, the pump light power is very high (30dBm) and can provide a 20dB gain to the signal light power (which can increase the signal light power to the SBS threshold power P). th (As mentioned above), Raman amplifiers in optical fibers not only generate nonlinearity in their own pump light (due to excessive pump light), but also in the amplification of the signal light. Therefore, the nonlinearity cost is mainly determined by the pump power of the Raman amplifier and the output power of the power amplifier. The greater the Raman pump power and the greater the output power of the power amplifier, the greater the signal amplification and the longer the transmission distance. Conversely, the greater the nonlinearity cost, the more unstable the corresponding system becomes.

[0051] Based on this research, the applicant conducted a series of experiments and designed a Raman transmission system, making the engineering commissioning of the Raman transmission system more efficient and accurate. It is worth noting that the deficiencies mentioned in the background section of the prior art are the result of the inventor's practical experience and careful research. Therefore, the discovery process of the above-mentioned problems and the solutions proposed by the inventors in the embodiments of the present invention below should all be considered contributions made by the inventors to the present invention.

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0053] To solve the above problems, such as Figure 1As shown, this embodiment of the invention provides a Raman transmission system connected to a near-end transmission device 30 (such as...). Figure 1 (left side of the middle) and remote transmission device 30' (e.g.) Figure 1 Between the right and middle sides, the Raman transmission system includes a first performance convergence unit 10, a first optical path subunit 20, a second optical path subunit 20', and a second performance convergence unit 10'.

[0054] The first performance convergence unit 10 is used to connect to the receiving end of the near-end transmission device 30 (e.g., Figure 1 The first optical path subunit 20 is used to connect to the transmitting end of the remote transmission device 30' (e.g., RX in the image), and the first optical path subunit 20 is used to connect to the transmitting end of the remote transmission device 30' (e.g., RX in the image). Figure 1 The first performance convergence unit 10' is used to connect the transmitting end of the near-end transmission device 30, and the second optical path subunit 20' is used to connect the receiving end of the far-end transmission device 30'. It is understood that "near-end" and "far-end" are convenient terms to describe the two ends of the communicating transmission devices 30, and the structure and function of the near-end transmission device 30 and the far-end transmission device 30' are generally completely identical. "Convergence" refers to the gradual achievement of optimal performance. The first performance convergence unit 10 and the second performance convergence unit 10' are used to adjust the Raman transmission system to its optimal transmission performance.

[0055] Both the first optical path subunit 20 and the second optical path subunit 20' include at least a power amplifier 21, a forward Raman amplifier 22, and a backward Raman amplifier 24. In practical applications, they also include a transmission fiber 23 and a preamplifier 25; wherein the power amplifier 21, forward Raman amplifier 22, transmission fiber 23, backward Raman amplifier 24, and preamplifier 25 are connected in sequence to amplify the service signal light and extend the service transmission distance. In the art, the Raman amplifier located on the transmitting end side is generally referred to as the forward Raman amplifier 22, and the Raman amplifier located on the receiving end side is referred to as the backward Raman amplifier 24. As mentioned above, the preamplifier 25 does not introduce nonlinear effects; therefore, in this embodiment of the invention, it is not necessary to determine the optimal output power of the preamplifier 25.

[0056] The first performance convergence unit 10 is used to acquire the service performance parameters of the receiving end of the near-end transmission device 30 in real time, and to notify the second performance convergence unit 10' to reduce the initial value of the output power of the power amplifier 21 of the first optical path subunit 20 and the pump power of the forward Raman amplifier 22 until the service performance parameters reach a preset threshold; wherein, the preset threshold and the initial value are selected by those skilled in the art according to the specific application scenario. It is also used to adjust the pump power of the backward Raman amplifier 24 of the first optical path subunit 20 after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and to take the backward Raman pump power at this time as the first power value (i.e., the optimal backward pump power is obtained). It is also used to, after the backward Raman amplifier 24 is at the first power value, notify the second performance convergence unit 10' to restore the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 to their initial values, and then reduce the pump power of the backward Raman amplifier 24 until the service performance parameters reach a preset threshold, and take the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 at this time as the second power value. It is also used to, when the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are at the second power value, notify the second performance convergence unit 10' to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to a preset rule, until the service performance parameters no longer deteriorate, and then restore the pump power of the backward Raman amplifier 24 to the first power value again; wherein, the preset rule is selected by those skilled in the art according to the specific application scenario.

[0057] The second performance convergence unit 10' is used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the first optical path subunit 20 according to the notification content sent by the first performance convergence unit 10.

[0058] In an optional embodiment, the second performance convergence unit 10' is used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the first optical path subunit 20 according to the notification content sent by the first performance convergence unit 10, including:

[0059] After receiving a notification to reduce the initial output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 of the first optical path subunit 20, the second performance convergence unit 10' reduces the output power of the power amplifier 21 by a preset first step length and reduces the pump power of the forward Raman amplifier 22 by a preset second step length until the service performance parameters of the receiving end of the near-end transmission device 30 reach a preset threshold; wherein, the preset first step length and the preset second step length are selected by those skilled in the art according to the specific application scenario.

[0060] In another optional embodiment, the second performance convergence unit 10' is used to, upon receiving a notification from the first performance convergence unit 10 that the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 are adjusted according to preset rules until the service performance parameters no longer deteriorate, specifically to:

[0061] Iterate through all combinations of the output power of power amplifier 21 and the pump power of forward Raman amplifier 22, recording all service performance parameters corresponding to different combinations. Find the optimal service performance parameter, and use the output power of power amplifier 21 and the pump power of forward Raman amplifier 22 corresponding to this optimal service performance parameter as the second power value. Adjust the output power of power amplifier 21 and the pump power of forward Raman amplifier 22 to the second power.

[0062] Correspondingly, the first performance convergence unit 10 is also used to adjust the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 of the second optical path subunit 20' according to the notification content sent by the second performance convergence unit 10'.

[0063] The second performance convergence unit 10' is further configured to acquire the service performance parameters of the receiving end of the remote transmission device 30' in real time, and notify the first performance convergence unit 10 to reduce the initial value of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 of the second optical path subunit 20' until the service performance parameters reach a preset threshold; it is also configured to adjust the pump power of the backward Raman amplifier 24 of the second optical path subunit 20' after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and take the backward Raman pump power at this time as the first power value; it is also configured to notify the first performance convergence unit 10 to restore the previous power value after the backward Raman amplifier 24 is at the first power value. After the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are reduced to their initial values, the pump power of the backward Raman amplifier 24 is reduced until the service performance parameters reach a preset threshold. The pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 at this time are taken as the second power value. It is also used to notify the first performance convergence unit 10 to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules when the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are the second power value, until the service performance parameters no longer deteriorate, and then restore the pump power of the backward Raman amplifier 24 to the first power value.

[0064] In some embodiments, such as Figure 2 As shown, the workflow of this Raman transmission system includes the following steps:

[0065] S101, the first performance convergence unit 10 acquires the service performance parameters of the receiving end of the near-end transmission device 30 in real time, and notifies the second performance convergence unit 10' to reduce the initial value of the output power of the power amplifier 21 of the first optical path subunit 20 and the pump power of the forward Raman amplifier 22 until the service performance parameters reach the preset threshold.

[0066] S102, the second performance convergence unit 10' reduces the output power of the power amplifier 21 by a preset first step length, and reduces the pump power of the forward Raman amplifier 22 by a preset second step length, until the service performance parameters of the receiving end of the remote transmission equipment 30' reach a preset threshold.

[0067] S103, the first performance convergence unit 10 increases or decreases the pump power of the backward Raman amplifier 24 by a preset third step size, and records the service performance parameters after each adjustment. The backward Raman pump power corresponding to the optimal service performance parameters is taken as the first power value, which is the optimal backward Raman pump power. The second performance convergence unit 10' is then notified to restore the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 to their initial values. The preset third step size is selected by those skilled in the art based on the specific application scenario.

[0068] S104, the second performance convergence unit 10' restores the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 to their initial values.

[0069] S105, the first performance convergence unit 10 further reduces the pump power of the backward Raman amplifier 24 until the service performance parameters reach the preset threshold. The pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 at this time are taken as the second power value, and the second performance convergence unit 10' is notified to adjust the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules until the service performance parameters no longer deteriorate.

[0070] S106, the second performance convergence unit 10' then adjusts the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to the preset rules.

[0071] S107, after the first performance convergence unit 10 detects that the service performance parameters are no longer deteriorating, it restores the pump power of the back-to-back Raman amplifier 24 to the first power value.

[0072] In order to realize the functions of the first performance convergence unit 10 and the second performance convergence unit 10', in some embodiments, the first performance convergence unit 10 or the second performance convergence unit 10' includes at least a first multiplexer / demultiplexer 11, an optical supervisory channel (OSC) 12, a second multiplexer / demultiplexer 11', and a controller 13.

[0073] The first input terminal of the first multiplexer / demultiplexer 11 is used to connect to the transmitter of the near-end transmission device 30, and the second input terminal is used to connect to the transmitter of the optical monitoring channel 12 (i.e., as shown in the image). Figure 5 As shown in the diagram (tx), the output of the first multiplexer 11 is used to connect to the second optical path subunit 20'. The receiver of the optical monitoring channel 12 (i.e., as shown in the diagram) is connected to the second optical path subunit 20'. Figure 5 The rx shown is connected to the first output terminal of the second multiplexer / demultiplexer 11'. The second output terminal of the second multiplexer / demultiplexer 11' is used to connect to the receiving terminal of the near-end transmission device 30, and the input terminal of the second multiplexer / demultiplexer 11' is used to connect to the output terminal of the first optical path subunit 20. The controller 13 is connected to the control terminal of the optical monitoring channel 12, the second optical path subunit 20', and the near-end transmission device 30, respectively.

[0074] The optical monitoring channel 12 is mainly used to transmit service performance parameters and adjustment commands for each amplifier between the first performance convergence unit 10 and the second performance convergence unit 10'. The multiplexer / demultiplexer is used to combine and demultiplex the optical monitoring channel light with the service light. The controller 13 is used to read and adjust the output power of the power amplifier 21, the pump power of the forward Raman amplifier 22, the pump power of the backward Raman amplifier 24, and to read the service performance parameters of the transmission equipment 30, such as the bit error rate or quality factor Q of forward error correction (FEC). It is also used to find the optimal backward pump power, optimal forward pump power, and optimal power of the power amplifier 21 according to preset rules. The optical monitoring channel 12 is connected to the controller 13 via a circuit, and the transmission equipment 30, each optical amplifier, the first performance convergence unit 10, and the second performance convergence unit 10' are connected via a serial port or Ethernet port.

[0075] For ease of understanding, we will now combine... Figure 1 The Raman transmission system provides a more detailed explanation of the steps to find the optimal back-Raman pump power:

[0076] In the initial stage of service line activation, the first performance convergence unit 10 obtains the service performance (such as the service FEC error rate or quality factor Q) of the receiving end of the near-end transmission equipment 30 through a serial port or network port. At the same time, it notifies the controller 13 of the remote second performance convergence unit 10' to reduce the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 in the first optical path subunit 20 until the service performance of the receiving end approaches the limit (i.e., the FEC error rate tolerance or the minimum value of the Q factor). The first performance convergence unit 10 then increases the backward Raman pump power value until the service performance of the receiving end no longer improves or deteriorates (i.e., the FEC error rate no longer decreases or the Q factor no longer increases). At this time, the backward Raman pump power is the optimal backward pump power. In this approach, on the one hand, since the nonlinearity generated by the signal amplification of the Raman amplifier and power amplifier 21 at the transmitting end, and the nonlinearity generated by the backward Raman amplifier in the optical fiber at the receiving end, both affect the service at the receiving end, reducing the forward Raman pump power and the output power of power amplifier 21 can eliminate the impact of the nonlinear effects generated at the transmitting end on the service at the receiving end, while only retaining the impact of the nonlinearity generated by the backward Raman amplifier 24 on the system. In this way, changes in the service performance at the receiving end of the system can only be attributed to the influence of the backward Raman amplifier 24, making system adjustment and judgment easier. On the other hand, in practical engineering applications, transmission systems reserve a large system margin (more than 5dB). At this time, the pre-correction bit error rate of the receiver service performance is very small (almost 0). The reference for the quality of system adjustment is the pre-correction bit error rate. If the pre-correction bit error rate of the receiver service is very small, the change in the pre-correction bit error rate can hardly be observed when adjusting the system parameters. It is unknown whether adjusting the parameters will improve or worsen the system performance. Therefore, it is necessary to ensure that the pre-correction bit error rate of the receiver service is within a suitable range (generally close to the pre-correction bit error rate tolerance). In this way, when adjusting the system, the change in the pre-correction bit error rate (i.e., increase or decrease) can well reflect the quality of the system parameter adjustment. In practical engineering applications, transmission systems typically reserve a large system margin (exceeding 5dB). Therefore, reducing the pump power of the forward Raman amplifier 22 and the power amplifier 21 does not generate bit errors; it only reduces the system margin. When the system has no margin, the service performance at the receiving end will approach the FEC correction tolerance. This process reduces or eliminates the nonlinearity generated at the transmitting end by sacrificing the system's reserved margin by reducing the output power of the transmitting power amplifier 21 and the pump power of the forward Raman amplifier 22.

[0077] When the service line is activated, assuming the initial state of the line, the output power of the power amplifier 21 of the first optical path subunit 20 is P1, the pump power of the forward Raman amplifier 22 is P2, and the pump power of the backward Raman amplifier 24 is P3, the output power of the power amplifier 21 (adjusted by gain) is adjusted in steps of Δ1 (typically 1dB), the pump power of the forward Raman amplifier 22 is adjusted in steps of Δ2 (typically 100mW), and the pump power of the backward Raman amplifier 24 is adjusted in steps of Δ3 (typically 100mW). Δ1, Δ2, and Δ3 can all be manually configured. The power amplifier 21 reduces its power by Δ1 each time. The pump power of the forward Raman amplifier 22 is reduced to Δ2 each time. After n adjustments, the output power of the power amplifier 21 is P1-n×Δ1, and the pump power of the forward Raman amplifier 22 is P2-n×Δ2. The service performance at the receiving end is close to the FEC correction tolerance. The FEC correction tolerance refers to the limit of bit error rate that FEC can correct, such as 3.2E-2. When the bit error rate exceeds this value, bit errors will occur. When it is less than this value, no bit errors will occur. For a specific near-end transmission device 30 or far-end transmission device 30', this value is known and fixed. During the debugging process, the smaller the bit error rate, the better the system performance. At this point, the first performance convergence unit 10 starts to adjust the backward Raman pump power, increasing or decreasing the pump power in steps of Δ3, and comparing the change in the bit error rate before correction of the service at the receiving end. After m adjustments, the backward Raman pump power value P3±m×Δ3 corresponding to the minimum bit error rate before correction is taken, which is the optimal backward pump power value.

[0078] In this embodiment, the controller 13 monitors the bit error rate performance of the receiver in real time through the optical monitoring channel 12. During the adjustment process, it ensures that the bit error rate is controlled below the FEC error rate tolerance (limit), so that the system will not generate bit errors and will not affect the system's communication.

[0079] In this embodiment, the value of m is determined after multiple adjustments; generally, 3 to 6 adjustments are needed to determine the value corresponding to the minimum bit error rate. During the adjustment process, the bit error rate will change, eventually exhibiting a parabolic distribution (e.g., ...). Figure 3 As shown in the figure, “±” in P3±m×Δ3 indicates searching for the optimal backward pump power to the left (-) or right (+). In this figure, the third point is the lowest point, and its pre-correction bit error rate corresponds to the optimal pump power of the backward Raman amplifier 24.

[0080] In some embodiments, after the backward Raman amplifier 24 of the first optical path subunit 20 reaches a first power value, the second performance convergence unit 10' restores the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 to their initial values. The first performance convergence unit 10 then reduces the pump power of the backward Raman amplifier until the service performance parameters reach a preset threshold. Then, it adjusts the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to preset rules until the service performance parameters no longer deteriorate. Finally, it restores the pump power of the backward Raman amplifier 24 to the first power value. Specifically, as shown... Figure 4 As shown, it includes the following steps:

[0081] S201, the controller 13 of the second performance convergence unit 10' traverses all combinations of the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22, and records all service performance parameters corresponding to different combinations.

[0082] For example, the output power of the power amplifier 21 is reduced by a preset first step length. While keeping the output power unchanged, the forward pump power is adjusted multiple times by a preset second step length. The service performance parameters corresponding to different pump powers are recorded respectively to determine the optimal service performance parameters corresponding to the current output power of the power amplifier 21.

[0083] Repeat the above steps multiple times, that is, continue to reduce the output power of the power amplifier 21 by the preset first step length, and adjust the forward pump power multiple times by the preset second step length; finally, obtain all service performance parameters corresponding to the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 for different combinations.

[0084] S202, find the optimal service performance parameters, and use the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 corresponding to these optimal service performance parameters as the second power value.

[0085] S203, adjust the output power of power amplifier 21 and pump power of forward Raman amplifier 22 to the second power value, and the controller 13 of the first performance convergence unit 10 adjusts the pump power of backward Raman amplifier to the first power value.

[0086] For ease of understanding, we will now combine... Figure 1 The Raman transmission system provides a more detailed explanation of the steps for finding the optimal output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22:

[0087] After the Raman pump power optimization is completed, the controller 13 of the remote second performance convergence unit 10' is notified through the optical monitoring channel 12 of the first performance convergence unit 10 and the optical monitoring channel 12 of the second optical path subunit 20' and the second performance convergence unit 10' to restore the output power of the power amplifier 21 and the forward Raman pump power to the initial values ​​P1 and P2 of the service line opening, and then the optimization process of the forward Raman pump power and the output power of the power amplifier 21 begins.

[0088] First, the first performance convergence unit 10 gradually reduces the pump power of the backward Raman amplifier and monitors the pre-correction bit error rate status of the service performance at the near-end transmission equipment 30. When the pre-correction bit error rate approaches the FEC error tolerance, the reduction of the backward Raman pump power is stopped. At this time, the second performance convergence unit 10' iterates and adjusts the output power of the transmitting power amplifier 21 and the magnitude of the forward Raman pump power, and compares them with the pre-correction bit error rate value of the service at the receiving end. The value of the power amplifier 21 and the forward Raman pump power corresponding to the minimum pre-correction bit error rate is selected as the optimal value of the output of the transmitting power amplifier 21 and the pump power of the forward Raman amplifier 22.

[0089] The specific traversal adjustment method is as follows: the output power of power amplifier 21 is increased to P1+Δ1 and kept constant; the pump power of forward Raman amplifier 22 is adjusted within a certain range, with an adjustment step size of Δ2 each time. Assuming 2n adjustments are made, the set of forward Raman pump power when the output power is P1+Δ1 is:

[0090] {P2-n×Δ2,P2-(n-1)×Δ2,...,P2,...,P2+(n+1)×Δ2,P2+2n×Δ2}

[0091] Each pump power value corresponds to a pre-correction bit error rate (BER) value for the received service. Within this set, there is always a minimum BER value. The forward Raman pump power corresponding to this minimum BER value is the optimally matched forward Raman pump power when the output power of power amplifier 21 is P1+Δ1. Record the forward Raman pump power value and the BER value of the received service at this point. Then, adjust the output power of power amplifier 21 to P1+2×Δ1. Following the same method, the optimal forward Raman power matching value and the BER value of the received service under this output power state can be obtained. Similarly, the optimally matched forward Raman pump power value and the corresponding BER value of the received service can be obtained under different power amplifier 21 output powers. After 2m adjustments, the output power of power amplifier 21 can be represented as the following set:

[0092] {P1-m×Δ1,P1-(m-1)×Δ1,...,P1,...,P1+(m+1)×Δ1,P1+2m×Δ1}

[0093] Each set of output power corresponds to an optimal forward Raman pump power, and the receiving end service also has a corresponding pre-correction bit error rate. Within this set of pre-correction bit error rates, after K adjustments, there exists a minimum pre-correction bit error rate value. The output power of power amplifier 21 corresponding to this value is P1 + K × Δ1, which is the optimal output power. The corresponding pump power of forward Raman amplifier 22 is the optimally matched pump power. Assuming Q adjustments, the forward Raman pump power value is P2 + Q × Δ2. This output power of power amplifier 21 and the pump power of forward Raman amplifier 22 represent the optimal power amplifier output power and optimal forward pump power at the transmitting end. Keeping the output power of power amplifier 21 and the pump power of forward Raman amplifier 22 unchanged, the pump power of backward Raman amplifier 24 is restored to P3 ± m × Δ3. This completes the entire self-optimization process of power amplifier 21, forward Raman amplifier 22, and backward Raman amplifier 24 in the Raman system.

[0094] If the Raman transmission system is activated from a remote location, the controller 13 of the first performance convergence unit 10 adjusts the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 of the second optical path subunit 20', and the pump power of the backward Raman amplifier 24 is adjusted by the second performance convergence unit 10'. The whole process is the same as in the above embodiment, and will not be described again here.

[0095] The Raman transmission system provided in this embodiment of the invention first eliminates the influence of the preamplifier on nonlinear effects. By reducing the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22, and comparing the service performance parameters at the receiving end, the optimal power value of the backward Raman pump is determined. Then, the pump power of the forward Raman amplifier 22 and the output power of the power amplifier 21 are restored to their initial values. The pump power of the backward Raman amplifier is then reduced until the service performance parameters reach a preset threshold. The output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 are then adjusted according to preset rules until the service performance parameters no longer deteriorate, thus obtaining the optimal output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22. Finally, the pump power of the backward Raman amplifier is restored to its optimal power value.

[0096] This invention, by adjusting the power of different amplifiers, simulates different states of service lines, accurately obtains the optimal power value of each amplifier, determines the optimal transmission performance of the system, solves the problem of relying on experience for debugging during the commissioning of Raman transmission systems, and greatly saves the commissioning time of Raman transmission systems.

[0097] In other embodiments, such as Figure 5 As shown, the first performance convergence unit 10 includes an optical attenuator 14. The input of the optical attenuator 14 is connected to the transmitter of the near-end transmission device 30, and its output is connected to the first input of the first multiplexer / demultiplexer 11. The second input of the first multiplexer / demultiplexer 11 is connected to the transmitter of the optical monitoring channel 12, and its output is connected to the second optical path subunit 20'. The receiver of the optical monitoring channel 12 is connected to the first output of the second multiplexer / demultiplexer 11'. The second output of the second multiplexer / demultiplexer 11' is connected to the receiver of the near-end transmission device 30, and its input is connected to the output of the first optical path subunit 20. The controller 13 is connected to the control terminal of the optical monitoring channel 12, the second optical path subunit 20', and the near-end transmission device 30, respectively.

[0098] The second performance convergence unit 10' adjusts the output power of the power amplifier 21 and the pump power of the forward Raman amplifier 22 according to preset rules until the first performance convergence unit 10 determines that the service performance parameters are no longer deteriorating. After the first performance convergence unit 10 restores the pump power of the backward Raman amplifier 24 to the first power value, the second performance convergence unit 10' also increases the attenuation value of the optical attenuator 14 based on the real-time acquired service performance parameters of the near-end transmission equipment 30 (such as the pre-correction bit error rate), until the service performance parameters of the near-end transmission equipment 30 reach a preset threshold (the pre-correction bit error rate is close to the error correction tolerance value). The increased value of the optical attenuator 14 is recorded as the current margin of the Raman transmission system. This margin can provide guidance for line splicing, patching, etc. (sponge loss and patching loss must not exceed the safety margin).

[0099] In the detailed description above, various features are combined together in a single embodiment to simplify the invention. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0100] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term “comprising” as used in the specification or claims is interpreted in a manner similar to the term “including,” just as “including,” is interpreted as a conjunction in the claims. Additionally, the use of any term “or” in the specification of the claims is intended to mean “non-exclusive or.”

Claims

1. A Raman transmission system, connected between a near-end transmission device (30) and a far-end transmission device (30'), characterized in that, The Raman transmission system includes: a first performance convergence unit (10), a first optical path subunit (20), a second optical path subunit (20'), and a second performance convergence unit (10'), wherein: The first performance convergence unit (10) is used to connect to the receiving end of the near-end transmission device (30), and the first optical path subunit (20) is used to connect to the transmitting end of the far-end transmission device (30'); the second performance convergence unit (10') is used to connect to the transmitting end of the near-end transmission device (30), and the second optical path subunit (20') is used to connect to the receiving end of the far-end transmission device (30'); The first optical path subunit (20) and the second optical path subunit (20') each include at least a power amplifier (21), a forward Raman amplifier (22), and a backward Raman amplifier (24); The first performance convergence unit (10) is used to acquire the service performance parameters of the receiving end of the near-end transmission device (30) in real time, and to notify the second performance convergence unit (10') to reduce the initial value of the output power of the power amplifier (21) of the first optical path subunit (20) and the pump power of the forward Raman amplifier (22) until the service performance parameters reach a preset threshold; it is also used to adjust the pump power of the backward Raman amplifier (24) of the first optical path subunit (20) after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and take the backward Raman pump power at this time as the first power value; it is also used to notify the second performance convergence unit (10') to restore the pump power of the forward Raman amplifier (22) and the power amplifier after the backward Raman amplifier (24) is at the first power value. The output power of (21) is reduced when the pump power of the forward Raman amplifier (22) is restored to its initial value and the output power of the power amplifier (21) is restored to its initial value. Then the pump power of the backward Raman amplifier (24) is reduced until the service performance parameters reach the preset threshold. The pump power of the forward Raman amplifier (22) and the output power of the power amplifier (21) are taken as the second power value. It is also used to notify the second performance convergence unit (10') to adjust the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) according to the preset rules when the pump power of the forward Raman amplifier (22) and the output power of the power amplifier (21) are the second power value, until the service performance parameters no longer deteriorate. Then the pump power of the backward Raman amplifier (24) is restored to the first power value. The second performance convergence unit (10') is used to adjust the pump power of the forward Raman amplifier (22) and the output power of the power amplifier (21) of the first optical path subunit (20) according to the notification content sent by the first performance convergence unit (10).

2. The Raman transmission system as described in claim 1, characterized in that, The first performance convergence unit (10) is also used to adjust the pump power of the forward Raman amplifier (22) and the output power of the power amplifier (21) of the second optical path subunit (20') according to the notification content sent by the second performance convergence unit (10'); The second performance convergence unit (10') is also used to acquire the service performance parameters of the receiving end of the remote transmission device (30') in real time, and to notify the first performance convergence unit (10) to reduce the initial value of the output power of the power amplifier (21) of the second optical path subunit (20') and the pump power of the forward Raman amplifier (22) until the service performance parameters reach a preset threshold; it is also used to adjust the pump power of the backward Raman amplifier (24) of the second optical path subunit (20') after the service performance parameters reach the preset threshold until the service performance parameters no longer deteriorate, and to take the backward Raman pump power at this time as the first power value; it is also used to notify the first performance convergence unit (10) to restore the pump power and power of the forward Raman amplifier (22) after the backward Raman amplifier (24) is at the first power value. The output power of amplifier (21) is reduced after the pump power of forward Raman amplifier (22) is restored to its initial value and the output power of power amplifier (21) is restored to its initial value. Then, the pump power of backward Raman amplifier (24) is reduced until the service performance parameters reach the preset threshold. The pump power of forward Raman amplifier (22) and the output power of power amplifier (21) at this time are taken as the second power value. It is also used to notify the first performance convergence unit (10) to adjust the output power of power amplifier (21) and the pump power of forward Raman amplifier (22) according to the preset rules when the pump power of forward Raman amplifier (22) and the output power of power amplifier (21) are the second power value, until the service performance parameters no longer deteriorate. Then, the pump power of backward Raman amplifier (24) is restored to the first power value.

3. The Raman transmission system as described in claim 1, characterized in that, The second performance convergence unit (10') is used to adjust the pump power of the forward Raman amplifier (22) and the output power of the power amplifier (21) of the first optical path subunit (20) according to the notification content sent by the first performance convergence unit (10), including: After receiving a notification to reduce the initial output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) of the first optical path subunit (20), the second performance convergence unit (10') reduces the output power of the power amplifier (21) by a preset first step length and reduces the pump power of the forward Raman amplifier (22) by a preset second step length until the service performance parameters of the receiving end of the near-end transmission device (30) reach a preset threshold. The first performance convergence unit (10) is further configured to, after the service performance parameter reaches a preset threshold, adjust the pump power of the backward Raman amplifier (24) of the first optical path subunit (20) until the service performance parameter no longer deteriorates, and take the backward Raman pump power at this time as the first power value, including: Increase or decrease the pump power of the backward Raman amplifier (24) according to the preset third step length, and record the service performance parameters after each adjustment. Take the backward Raman pump power corresponding to the best service performance parameters as the first power value. The second performance convergence unit (10') is notified to adjust the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) according to the preset rules until the service performance parameters no longer deteriorate, and then the pump power of the backward Raman amplifier (24) is restored to the first power value.

4. The Raman transmission system as described in claim 3, characterized in that, The second performance convergence unit (10') is used, after receiving a notification from the first performance convergence unit (10) to adjust the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) according to preset rules, to further: Traverse all combinations of the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22), and record all service performance parameters corresponding to different combinations; Find the optimal service performance parameters, and use the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) corresponding to these optimal service performance parameters as the second power value; Adjust the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) to the second power.

5. The Raman transmission system as described in claim 4, characterized in that, The second performance convergence unit (10') iterates through all combinations of the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22), and records all service performance parameters corresponding to different combinations, including: The output power of the power amplifier (21) is reduced by a preset first step length. While keeping the output power unchanged, the forward pump power is adjusted multiple times by a preset second step length. The service performance parameters corresponding to different pump powers are recorded respectively, and the optimal service performance parameters corresponding to the current power amplifier output power are determined. Repeat the above steps multiple times to continue reducing the output power of the power amplifier (21) by the preset first step length and to adjust the forward pump power multiple times by the preset second step length, and finally obtain all service performance parameters corresponding to the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) for different combinations.

6. The Raman transmission system as described in claim 1, characterized in that, The first performance convergence unit (10) includes at least a first multiplexer / demultiplexer (11), an optical monitoring channel (12), a second multiplexer / demultiplexer (11'), and a controller (13), wherein: The first input terminal of the first multiplexer (11) is used to connect to the transmitting end of the near-end transmission device (30), the second input terminal is used to connect to the transmitting end of the optical monitoring channel (12), and the output terminal of the first multiplexer (11) is used to connect to the first optical path subunit (20). The receiving end of the optical monitoring channel (12) is connected to the first output end of the second multiplexer (11'); The second output terminal of the second multiplexer (11') is used to connect to the receiving end of the near-end transmission device (30), and the input terminal of the second multiplexer (11') is used to connect to the output terminal of the first optical path subunit (20). The controller (13) is connected to the control end of the optical monitoring channel (12), the second optical path sub-unit (20'), and the near-end transmission device (30), respectively.

7. The Raman transmission system as described in claim 1, characterized in that, The first performance convergence unit (10) further includes an optical attenuator (14), the input of which is connected to the transmitting end of the near-end transmission device (30), and the output is connected to the first input of the first multiplexer (11).

8. The Raman transmission system as described in claim 7, characterized in that, After adjusting the output power of the power amplifier (21) and the pump power of the forward Raman amplifier (22) according to the preset rules until the service performance parameters no longer deteriorate, and then restoring the pump power of the backward Raman amplifier (24) to the first power value, the second performance convergence unit (10') is also used to increase the attenuation value of the optical attenuator (14) until the service performance parameters of the receiving end of the near-end transmission device (30) reach the preset threshold, and then recording the increase in the attenuator value as the current margin of the Raman transmission system.

9. The Raman transmission system as described in claim 1, characterized in that, The service performance parameters are the FEC error rate or quality factor before correction.

10. The Raman transmission system as described in claim 1, characterized in that, Both the first optical path subunit (20) and the second optical path subunit (20') further include a transmission optical fiber (23) and a preamplifier (25); wherein, the power amplifier (21), the forward Raman amplifier (22), the transmission optical fiber (23), the backward Raman amplifier (24) and the preamplifier (25) are connected in sequence.

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