Stimulated raman scattering compensation device and method

Abstract

The embodiment of the application discloses a stimulated Raman scattering compensation device and method, which is applied to the field of optical communication and can be arranged in a relay node in an optical communication system. The device comprises an optical beam splitter, a power distribution detector, a wavelength division demultiplexer, a wavelength converter array and a wavelength division multiplexer. The device realizes power spectrum detection of multiple second signal lights by the power distribution detector and wavelength converter array, generates a feedback control signal, and controls the wavelength converter array to adjust the power spectrum of the signal light, so that the power of the adjusted signal light is arranged from high to low in a target wavelength band from short wavelength to long wavelength, the SRS effect is compensated, and the signal light is ensured to enter the fiber again after adjustment. The SRS effect is used to make the short-wave light power smaller and the long-wave light power larger, so that the power of the signal light is flat.

Description

Technical Field

[0001] This application relates to the field of optical communication, and in particular to a stimulated Raman scattering compensation device and method. Background Technology

[0002] With the surge in global data traffic, the capacity of a single optical fiber needs to be further increased to meet the growing demand. Optical communication systems improve single-fiber capacity by extending the transmission band, but as the transmission bandwidth increases, the optical power entering the fiber also increases, leading to increasingly strong nonlinear effects during signal transmission. Stimulated Raman scattering (SRS) is particularly severe, manifested as a continuous transfer of power from short-wavelength channels to long-wavelength channels, i.e., power decreases at short wavelengths and amplifies at long wavelengths. This causes a decrease in the system's optical signal-to-noise ratio (OSNR). After multiple transmission segments, the power flatness of the broadband signal further deteriorates, resulting in severe system performance degradation.

[0003] Therefore, to avoid system performance degradation, it is necessary to compensate for the SRS effect in the optical link. Currently, Raman pump lasers can be installed in the link, using the transmission fiber as the gain medium to perform distributed Raman amplification of the signal light, thus compensating for power loss at shorter wavelengths and achieving gain balance across wavelengths to some extent. However, this Raman amplification method requires adding a large number of Raman pump lasers to the link, resulting in complex deployment and increased equipment deployment costs for the optical communication system. Summary of the Invention

[0004] This application provides a stimulated Raman scattering compensation device and method. The stimulated Raman scattering compensation device is used to compensate for the SRS effect in optical fiber, realize gain equalization of each channel, and improve the overall transmission performance of the optical communication system.

[0005] In a first aspect, embodiments of this application provide a stimulated Raman scattering compensation device, comprising: an optical beam splitter, a power distribution detector, a wavelength division multiplexer, a wavelength converter array, and a wavelength division multiplexer;

[0006] Among them, the optical beam splitter is used to receive the multiplexed first signal light, output a portion of the first signal light to the power distribution detector, and output another portion of the first signal light to the wave demultiplexer;

[0007] A power distribution detector is used to separate the first signal light into multiple second signal lights, detect the power spectrum of the multiple second signal lights, and generate a feedback control signal based on the power spectrum.

[0008] Wavelength demultiplexer is used to separate a first signal light into multiple second signal lights, and transmit the multiple second signal lights to the corresponding wavelength converters respectively;

[0009] A wavelength converter array is used to convert the wavelengths of multiple second signal lights according to feedback control signals in order to adjust the power spectrum of the multiple second signal lights and output the adjusted multiple third signal lights. The power of the multiple third signal lights is arranged from high to low in the target wavelength band from short wavelength to long wavelength.

[0010] A wavelength division multiplexer is used to synthesize multiple third-channel optical signals and output them.

[0011] In this example, the SRS compensation device, through the cooperation of a power distribution detector and a wavelength converter array, enables the power distribution detector to detect the power spectrum of the signal light and generate a feedback control signal. This feedback control signal further controls the wavelength converter array to adjust the power spectrum of the signal light, ensuring that the power of the adjusted signal light is arranged from high to low across the target wavelength range from short to long wavelengths. This compensates for the SRS effect, ensuring that when the adjusted signal light re-enters the fiber, the SRS effect reduces the power of short-wavelength light and increases the power of long-wavelength light, thus achieving power flatness of the signal light. This application achieves SRS compensation for optical communication systems with fewer components, resulting in lower cost and suitability for large-scale use. Furthermore, the SRS device is deployed at the relay node, without adding extra deployment workload.

[0012] In one possible implementation, the wavelength converter is further configured to receive a second signal light of a first wavelength, which is the wavelength to be converted. The wavelength converter controls the wavelength position and power of the pump light according to a feedback control signal, and generates an idler light at a second wavelength based on the second signal light of the first wavelength and the pump light. The second wavelength is the wavelength after wavelength conversion. Then, the wavelength converter filters out the idler light, which becomes the third signal light. The wavelength conversion method in this example has a response rate on the femtosecond scale and is transparent to the transmitted data format. It can realize wavelength conversion and power adjustment for signal light with various modulation formats, and is applicable to a wide range of scenarios.

[0013] In one possible implementation, the power distribution detector is further configured to generate a first control signal when the power spectrum of the multiple second signal lights is detected to increase sequentially with wavelength; the wavelength converter is further configured to control the wavelength position of the pump light according to the first control signal, so that the positions of the first wavelength and the second wavelength are axially symmetrical in the target band; and to control the power of the pump light so that the power of the idler light is the same as the power of the second signal light at the first wavelength. In this example, when the power spectrum of the second signal light increases sequentially with wavelength, it is not necessary to change the power of the second signal light; only the wavelength of the second signal light needs to be adjusted to transform the wavelength to the axially symmetrical wavelength position, thereby arranging the power of the multiple third signal lights from high to low in the target band from short wavelength to long wavelength, achieving SRS compensation.

[0014] In one possible implementation, the power distribution detector is further configured to generate a second control signal when the power of multiple second signal lights is detected to be equal; the wavelength converter is further configured to control the wavelength position of the pump light according to the second control signal, so that the second wavelength position is located at the target sequence position in the target band; and then control the power of the pump light according to the target sequence position of the second wavelength, so as to control the power of the idler light, so that the power of the idler light is located at the target sequence position in the power spectrum of multiple third signal lights. In this example, the power of the multiple second signal beams is equal. Therefore, for one of the multiple second signal beams, its position can be changed to an arbitrary wavelength position. However, the target sequence position (i.e., the order of priority) of this wavelength position within the target band must be recorded. The wavelength converter controls the wavelength position of the second pump light according to the second control signal, ensuring that the second wavelength position is at the target sequence position within the target band. The wavelength converter then controls the power of the second pump light based on the target sequence position of the second wavelength, thereby controlling the power of the idler light, ensuring that the power of the idler light is at the target sequence position in the power spectrum of the multiple third signal beams. Finally, the power spectra of the multiple idler beams (i.e., the multiple third signal beams) output by the wavelength converter array are arranged from high to low according to wavelength, achieving SRS compensation.

[0015] In one possible implementation, the power distribution detector is further configured to generate a third control signal when the power of the second signal light at the first wavelength is detected to be at the Xth position in the power spectrum arranged from largest to smallest. The wavelength converter is further configured to control the wavelength position of the pump light according to the third control signal to generate idler light at the second wavelength, wherein the second wavelength is the wavelength at the Xth position in the target band. In another possible implementation, the wavelength converter is further configured to control the power of the pump light according to the Xth position to control the power of the idler light, such that the power of the idler light is at the Xth position in the power spectrum of the multiple third signal lights. In this example, when the power distribution of multiple second signal lights does not conform to the general rule (which refers to the situation where the power of multiple second signal lights gradually increases or decreases with wavelength, or the power of multiple second signal lights is equal), the power of the multiple second signal lights is detected by the power distribution detector. First, the power order of the second signal light at a certain wavelength in the power spectrum is determined. For example, if the second signal light has a wavelength of λ1 and a power of P1, and P1 is ranked third in the power spectrum, then the first wavelength converter generates idler light at the third wavelength position (i.e., λ3) according to this third order, that is, the wavelength of the second signal light is converted to λ3. Thus, the power spectrum of the multiple idler lights (i.e., multiple third signal lights) output by the wavelength converter array is arranged from high to low with wavelength, achieving SRS compensation.

[0016] In one possible implementation, the power distribution detector is further configured to generate a fourth control signal when the detected power of the multiple signal beams decreases sequentially with wavelength; the wavelength converter is further configured to control the power of the pump light to 0 according to the fourth control signal. Since the power of the multiple second signal beams already satisfies the requirement of decreasing power with wavelength, wavelength conversion of the multiple second signal beams is not necessary; that is, the wavelength converter controls the pump laser to shut down and does not process the multiple second signal beams. In this example, the power distribution detector detects the power spectrum of the multiple second signal beams and generates a feedback control signal based on the specific characteristics of the power spectrum. The wavelength converter dynamically and selectively performs wavelength conversion on the signal beams and controls the power of the idler beams based on different power spectrum conditions, achieving a power distribution of the signal beams in all channels that decreases sequentially with wavelength (from short to long wavelength), so that the third signal beam achieves power flatness across all channels after entering the next fiber optic link for transmission.

[0017] In one possible implementation, the power distribution detector includes a beam splitter, a photodetector array, and a control unit;

[0018] A beam splitter is used to receive a first signal light, split the first signal light into multiple second signal lights, and transmit the multiple second signal lights to corresponding photodetectors; a photodetector is used to convert the second signal light into an electrical signal and transmit the electrical signal to a control unit; a control unit is used to determine the power spectrum of the multiple second signal lights based on the electrical signal and generate a feedback control signal based on the power spectrum.

[0019] In one possible implementation, the power difference between any two adjacent third signal beams in the multiple third signal beams is the same. This ensures that the difference between adjacent third signal beams is not too large, and by utilizing the SRS effect, power flatness is achieved across all channels after the third signal beams enter the next fiber optic link for transmission.

[0020] In one possible implementation, the target bands include the C-band and the L-band.

[0021] The second aspect provides a stimulated Raman scattering compensation method, which is applied to the stimulated Raman scattering compensation device described in the first aspect above. The stimulated Raman scattering compensation device includes: an optical beam splitter, a power distribution detector, a wavelength division multiplexer, a wavelength converter array, and a wavelength division multiplexer; the method includes:

[0022] The first signal light is received by an optical beam splitter, a portion of the first signal light is output to a power distribution detector, and another portion of the first signal light is output to a wave demultiplexer.

[0023] The first signal light is separated into multiple second signal lights by a power distribution detector, and the power spectrum of the multiple second signal lights is detected; and a feedback control signal is generated based on the power spectrum.

[0024] The first signal light is separated into multiple second signal lights by a wavelength demultiplexer, and the multiple second signal lights are transmitted to the corresponding wavelength converters respectively.

[0025] The wavelength converter array converts the wavelengths of multiple second signal lights according to the feedback control signal to adjust the power spectrum of the multiple second signal lights, and outputs the adjusted multiple third signal lights. The power of the multiple third signal lights is arranged from high to low in the target wavelength band from short wavelength to long wavelength.

[0026] Multiple third-channel optical signals are synthesized and output using a wavelength division multiplexer.

[0027] In one possible implementation, the wavelengths of multiple second signal lights are converted according to a feedback control signal using a wavelength converter array, including:

[0028] The second signal light of the first wavelength is received by the wavelength converter. The wavelength position and power of the pump light are controlled according to the feedback control signal. The idler light is generated on the second wavelength according to the second signal light of the first wavelength and the pump light. The idler light is filtered out. The idler light is the third signal light.

[0029] In one possible implementation, the power spectrum of the multiple second signal beams is detected by a power distribution detector, and a feedback control signal is generated based on the power spectrum, including:

[0030] When the power spectrum of the multiple second signal lights is detected by the power distribution detector to increase with wavelength, a first control signal is generated.

[0031] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0032] The wavelength converter controls the position of the pump light according to the first control signal, so that the positions of the first wavelength and the second wavelength are axially symmetrical in the target band; and controls the power of the pump light so that the power of the idler light is the same as the power of the second signal light of the first wavelength.

[0033] In one possible implementation, the power spectrum of the multiple second signal beams is detected by a power distribution detector, and a feedback control signal is generated based on the power spectrum, including:

[0034] When the power distribution detector detects that the power of multiple signal beams is equal, a second control signal is generated.

[0035] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0036] The wavelength converter controls the wavelength position of the pump light according to the second control signal, so that the second wavelength position is located at the target sequence position in the target band; the power of the pump light is controlled according to the target sequence position of the second wavelength, so as to control the power of the idler light, so that the power of the idler light is located at the target sequence position in the power spectrum of the multiple third signal lights.

[0037] In one possible implementation, the power spectrum of the multiple second signal beams is detected by a power distribution detector, and a feedback control signal is generated based on the power spectrum, including:

[0038] When the power of the second signal light at the first wavelength is detected by the power distribution detector and is located at the Xth position in the power spectrum from largest to smallest, a third control signal is generated.

[0039] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0040] The wavelength position of the pump light is controlled by the wavelength converter according to the third control signal, and idler light is generated at the second wavelength, which is the wavelength located at the Xth position in the target band.

[0041] In one possible implementation, the method also includes:

[0042] The power of the pump light is controlled by the wavelength converter according to the Xth sequence position, so as to control the power of the idler light and make the power of the idler light located at the Xth sequence position in the power spectrum of the multiple third signal lights.

[0043] In one possible implementation, the power spectrum of the multiple second signal beams is detected by a power distribution detector, and a feedback control signal is generated based on the power spectrum, including:

[0044] When the power of the multi-channel signal light is detected by the power distribution detector to decrease successively with wavelength, a fourth control signal is generated.

[0045] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0046] The wavelength converter is also used to control the power of the pump light to be 0 according to the fourth control signal.

[0047] In one possible implementation, the power distribution detector includes a beam splitter, a photodetector array, and a control unit; the power distribution detector separates the first signal light into multiple second signal lights, detects the power spectra of the multiple second signal lights, and generates a feedback control signal based on the power spectra, including:

[0048] The first signal light is received by a beam splitter, the first signal light is separated into multiple second signal lights, and the multiple second signal lights are transmitted to the corresponding photodetectors respectively.

[0049] The second signal light is converted into an electrical signal by a photodetector and then transmitted to the control unit.

[0050] The control unit determines the power spectrum of the multiple second signal lights based on the electrical signal and generates a feedback control signal based on the power spectrum.

[0051] In one possible implementation, the power difference between two adjacent third signal beams in the multiple third signal beams is the same. Attached Figure Description

[0052] Figure 1 A schematic diagram illustrating the power transfer from shortwave to longwave caused by the SRS effect;

[0053] Figure 2A This is a schematic diagram illustrating an example of an optical communication system in an embodiment of this application.

[0054] Figure 2B This is a schematic diagram of another example of an optical communication system in the embodiments of this application;

[0055] Figure 3 This is a schematic diagram of an example of an SRS compensation device in an embodiment of this application;

[0056] Figure 4 This is a schematic diagram illustrating an example of how the SRS compensation device adjusts the power spectrum of multiple second signal lights in an embodiment of this application.

[0057] Figure 5 This is a schematic diagram of an example of a power distribution detector in an embodiment of this application;

[0058] Figure 6 This is a schematic diagram illustrating the working principle of the wavelength converter in the embodiments of this application;

[0059] Figure 7A This is a schematic diagram illustrating an example of the transfer of modulation information of the signal light to the idler light in an embodiment of this application.

[0060] Figure 7B This is a schematic diagram illustrating another example of the transfer of modulation information of the signal light to the idler light in an embodiment of this application;

[0061] Figure 8A This is a schematic diagram illustrating how the wavelength converter array adjusts the power spectrum of the multiple second signal lights as the power spectrum of the multiple second signal lights increases with wavelength in an embodiment of this application.

[0062] Figure 8B This is a schematic diagram illustrating how the wavelength converter array adjusts the power spectrum of the multiple second signal lights when the power of the multiple second signal lights is equal in an embodiment of this application.

[0063] Figure 8C and 8D This is a schematic diagram illustrating how the wavelength converter array adjusts the power spectrum of multiple second signal lights when the power distribution of the multiple second signal lights is disordered in an embodiment of this application.

[0064] Figure 8E This is a schematic diagram of the power spectrum processing of multiple second signal lights by the wavelength converter array when the power of multiple signal lights decreases with each wavelength in an embodiment of this application.

[0065] Figure 9 This is a schematic diagram illustrating the application scenario of the SRS compensation device in the embodiments of this application;

[0066] Figure 10 This is a flowchart illustrating an example of the SRS compensation method in an embodiment of this application. Detailed Implementation

[0067] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices.

[0068] SRS (Spark Reduction) refers to a nonlinear optical effect in which strong interactions occur between signal light and molecules, leading to coupling between the two light waves and causing light scattering. This scattering process exhibits stimulated emission properties, resulting in Raman scattering. This nonlinear optical effect is called stimulated Raman scattering. In multi-channel wavelength division multiplexing (WDM) systems, SRS caused by long wavelengths exciting short wavelengths can occur between multiple light waves transmitted through a single optical fiber, resulting in coupling between the light waves. Figure 1 As shown, the optical power of short wavelengths decreases while the optical power of long wavelengths increases, meaning that optical power is transferred from short wavelengths to long wavelengths. The uneven optical power distribution between different wavelength channels reduces the overall transmission performance of the optical communication system.

[0069] This application provides an SRS compensation device applied to an optical communication system. (See also...) Figure 2A As shown, the communication system includes a transmitter 201, a relay node 202, and a receiver 203. The transmitter 201 converts an electrical signal into an optical signal and then transmits the optical signal into an optical fiber. The relay node 202 receives the optical signal, processes it, and then relays it into the optical fiber. The receiver 203 receives the optical signal from the optical fiber, converts it back into an electrical signal, and performs demodulation. The relay node 202 includes, but is not limited to, optical cross-connectors or repeaters, and the number of relay nodes 202 is not limited. Figure 2A The optical communication system topology shown is a linear topology. This application does not limit the topology of the optical communication system; for example, the optical communication system can also be as follows: Figure 2BThe complex network topology shown, or other topologies (such as ring topologies), are all acceptable in an optical communication system as long as they include relay nodes. This application provides a method for SRS compensation at relay nodes. The SRS compensation device can be a standalone device deployed at the relay node in the optical communication system, or it can be integrated into the relay node. For example, the SRS compensation device can be integrated into an optical cross-connector or repeater; the specific method is not limited.

[0070] In this application, the SRS compensation device, through the cooperation of a power distribution detector and a wavelength converter array, enables the power distribution detector to detect the power spectrum of the signal light and generate a feedback control signal. This feedback control signal further controls the wavelength converter array to adjust the power spectrum of the signal light, ensuring that the power of the adjusted signal light is arranged from high to low across the target wavelength range from short to long wavelengths. This compensates for the SRS effect, ensuring that when the adjusted signal light re-enters the fiber, the SRS effect reduces the power of short-wavelength light and increases the power of long-wavelength light, thus achieving power flatness of the signal light. This application achieves SRS compensation for optical communication systems with fewer components, resulting in lower costs and suitability for large-scale use. Furthermore, the SRS device is deployed at the relay node, without adding extra deployment workload.

[0071] Please see Figure 3 As shown, the SRS compensation device includes an optical beamsplitter 301, a power distribution detector 302, a wavelength division multiplexer 303, an array of wavelength converters 304, a wavelength division multiplexer 305, and an amplifier 306. The optical beamsplitter 301 receives a first signal light, outputs a portion of the first signal light to the power distribution detector 302, and outputs another portion of the first signal light to the wavelength division multiplexer 303. The first signal light is a multiplexed signal light. The power distribution detector 302 splits the first signal light into multiple second signal lights, which are the signal lights obtained after wavelength division of the first signal light. The power distribution detector 302 detects the power spectrum of the multiple second signal lights and generates a feedback control signal based on the power spectrum. This feedback control signal is used to control the wavelength converter 304 to perform corresponding operations. The wavelength division multiplexer 303 splits the first signal light into multiple second signal lights and transmits each of the multiple second signal lights to its corresponding wavelength converter 304. The wavelength converter array 304 converts the wavelengths of multiple second signal beams according to the feedback control signal to adjust the power spectrum of the multiple second signal beams, and outputs adjusted multiple third signal beams. The power of the multiple third signal beams is arranged from high to low in the target wavelength band from short wavelength to long wavelength. The wavelength division multiplexer 305 is used to synthesize the multiple third signal beams and multiplex them into a single optical signal for transmission to the amplifier 306. The amplified signal beam then enters the next fiber optic link for transmission.

[0072] Please see Figure 4 As shown, SRS compensation is performed at the relay node in the optical communication system (i.e., the SRS compensation device of this application is deployed between points B and C). For example, the SRS compensation device detects the power spectrum of the multiple second signal lights from point B, i.e., the power spectrum includes the power of each second signal light. Then, the SRS compensation device generates a feedback control signal based on the detected power spectrum, and further transforms the wavelength of the multiple second signal lights according to the feedback control signal to adjust the power spectrum of the multiple second signal lights. The adjusted multiple third signal lights are then combined and output to point C. Then, utilizing the SRS effect in the next fiber segment (from point C to point D), the SRS effect causes the power of short-wavelength optical light to shift to long-wavelength optical power during the transmission of the third signal light from point C to point D. Therefore, when the third signal light reaches point D, i.e., before entering the next fiber segment, the power spectrum of each wavelength channel is flattened.

[0073] First, let me explain some of the terms used in this application:

[0074] Power spectrum: This represents the variation of optical power (or simply "power") of a signal light with wavelength, or the distribution of signal light power across a wavelength band. The power spectrum can represent the relationship between signal light and wavelength. For example, the power spectrum curve (or power spectrum envelope) can also represent the relationship between signal light and wavelength. Please refer again. Figure 1 As shown, for example, the power of the signal light with wavelength λ1 is P1, the power of the signal light with wavelength λ2 is P2, ..., and the power of the signal light with wavelength λ... n The power of the signal light is P n Wait, the power spectrum curve is connected to P1, P2, ..., P n The connecting wire.

[0075] The first signal light is a multiplexed signal light, for example, with wavelengths λ1, λ2, ..., λ... n Multiple signal beams are multiplexed, and the multiplexed signal beam is the first signal beam.

[0076] The second signal light is the signal light obtained by wave decomposing the first signal light. For example, after wave decomposing the first signal light, λ1, λ2, ..., λ n Multiple signal beams, each of which is a second signal beam.

[0077] The third signal light is the signal light obtained by wavelength conversion of the second signal light. For example, the optical power of the second signal light with wavelength λ1 is P. n After wavelength conversion, the power remains constant, and the wavelength is λ. n The optical power of the third signal light is P nFor example, the power spectrum of the multiple second signal beams is: from λ1 to λ... n In the band, the power is P1, P2, ..., P n After power spectrum adjustment, the power spectrum is between λ1 and λ2. n In the band, the power spectrum is P n P n-1 , ..., P1, the adjusted multi-channel signal light is a multi-channel third signal light.

[0078] The components and operating process of the SRS compensation device in the embodiments of this application are described below:

[0079] Please refer again to Figure 3. The SRS compensation device includes: an optical beam splitter 301, a power distribution detector 302, a wavelength division multiplexer 303, a wavelength converter array 304, and a wavelength division multiplexer 305.

[0080] Optical beam splitter 301: used to receive the first signal light, output a portion of the first signal light to the power distribution detector 302, and output another portion of the first signal light to the wave demultiplexer 303.

[0081] Optical beam splitter 301 is an optical device used to split a beam of light into two or more beams. First, optical beam splitter 301 receives a first signal light (λ1, λ2, ..., λ3) from the fiber optic link. n The multiplexed signal light is then split into two beams according to a certain power ratio. One part of the first signal light is output to the power distribution detector 302, while the other part of the first signal light is output to the wave demultiplexer 303 while keeping the original transmission path unchanged.

[0082] Wavelength demultiplexer 303: Used to separate the first signal light into multiple second signal lights, and transmit the multiple second signal lights to the corresponding wavelength converters 304 respectively. To distinguish it from the wavelength demultiplexer in the power distribution detector, this wavelength demultiplexer 303 can also be called the "first wavelength demultiplexer".

[0083] First, the first-wave demultiplexer spatially separates the first signal light (i.e., broadband signal light) into n spatial channels, each spatial channel corresponding to one or more wavelength channels. For example, in the first implementation, the first-wave demultiplexer separates the first signal light into multiple wavelength channels according to the wavelength of the signal light, such as λ1, λ2, ..., λ n (λ1<λ2<…<λ n In the first implementation, each spatial channel corresponds to one wavelength channel. In the second implementation, each spatial channel can correspond to multiple wavelength channels, where the center wavelengths of each spatial channel are λ1, λ2, ..., λ3. n And λ1<λ2<…<λn For example, the first spatial channel corresponds to λ. a and λ b , λ a and λ b The center wavelength is λ1; the second spatial channel corresponds to λ. c and λ d , λ c and λ d The center wavelength is λ2, etc. For ease of explanation, this example uses the first implementation method, where n spatial channels are n wavelength channels (or simply "channels").

[0084] Power distribution detector 302: used to separate the first signal light into multiple second signal lights, detect the power spectrum of the multiple second signal lights, and generate a feedback control signal based on the power spectrum.

[0085] Please see Figure 5 As shown, the power distribution detector 302 includes a beam splitter 3021, a photoelectric converter 3022, and a control unit 3023. The photoelectric converter 3022 includes multiple photodetectors (i.e., a photodetector array). The beam splitter 3021 can be a wave demultiplexer, or it can be a grating. In this example, the beam splitter 3021 is described as a wave demultiplexer. To distinguish it from the wave demultiplexer 303 described above, this wave demultiplexer can also be called a "second wave demultiplexer." The control unit can be a field-programmable gate array (FPGA) chip.

[0086] First, the second-wave demultiplexer spatially separates the first signal light (i.e., broadband signal light) into n spatial channels, each spatial channel corresponding to one or more wavelength channels. For an understanding of how the second-wave demultiplexer spatially divides the first signal light into n spatial channels, please refer to the description of the first signal light being spatially divided into n spatial channels by wave demultiplexer 303 mentioned above. In this example, the n spatial channels are illustrated using n wavelength channels as an example.

[0087] Then, the second-wave demultiplexer transmits the signal light from each wavelength channel to the corresponding photodetector. The photodetector converts the optical power of the received signal light into a corresponding electrical signal, which is then transmitted to the control unit.

[0088] Finally, the control unit determines the electrical signal magnitude of each channel based on its internal algorithm, and then obtains the optical power of the signal light in each channel based on the electrical signal magnitude (e.g., determining the optical power based on the proportionality between the electrical signal voltage and the optical power). The control unit generates a feedback control signal based on the power spectrum of the multiple second signal lights (i.e., the optical power distribution information of the n channels). The feedback control signal is used to control the operation of the wavelength converter 304 array, specifically controlling the wavelength position and power of the pump light of each wavelength converter 304.

[0089] Wavelength converter 304 array: used to convert the wavelength of multiple second signal lights according to the feedback control signal, so as to adjust the power spectrum of the multiple second signal lights and output the adjusted multiple third signal lights. The power of the multiple third signal lights is arranged from high to low in the target wavelength band from short wavelength to long wavelength.

[0090] First, the wavelength converter array 304 includes n independently operating wavelength converters 304. For example, the wavelength converter array 304 includes a first wavelength converter, a second wavelength converter, ..., an nth wavelength converter. Each wavelength converter receives signal light corresponding to one wavelength channel. For example, the first wavelength converter receives second signal light with wavelength λ1, the second wavelength converter receives second signal light with wavelength λ2, and the nth wavelength converter receives signal light with wavelength λ... n The second signal light, etc.

[0091] Next, taking a wavelength converter as an example, the principle of wavelength conversion of wavelength converter 304 will be explained:

[0092] Please see Figure 6 As shown, exemplarily, the wavelength converter 304 may include a pump laser 3041, an optical amplifier 3042, a first filter 3043, a coupler 3044, an optical nonlinear medium 3045, and a second filter 3046. The pump laser 3041, optical amplifier 3042, first filter 3043, coupler 3044, optical nonlinear medium 3045, and second filter 3046 are connected sequentially according to the direction of light transmission.

[0093] First, the pump laser 3041 emits pump light at a low power and transmits it to the optical amplifier 3042.

[0094] Secondly, the optical amplifier 3042 amplifies the pump light, increases the optical power of the pump light, and transmits the amplified pump light to the first filter 3043.

[0095] Therefore, the first filter 3043 filters out the spontaneous emission noise generated by the optical amplifier 3042, and the filtered pump light (e.g., the pump light wavelength is λ) PTransmitted to coupler 3044.

[0096] Then, coupler 3044 will couple the signal light (e.g., the wavelength of the signal light is λ) S The amplified and filtered pump light is coupled into the optical nonlinear medium 3045.

[0097] Subsequently, the pump light and signal light are mixed in the optical nonlinear medium 3045 to generate idler light (e.g., wavelength λ) through four-wave mixing (or three-wave mixing). I This process transfers the modulated signal on the optical carrier to the idler light, completing the wavelength conversion and information transfer of the signal light. The optical nonlinear medium 3045 includes second- or third-order nonlinear optical devices, such as: highly nonlinear fiber (HNLF), periodically poled lithium niobate (PPLN), semiconductor optical amplifier (SOA), III-V group waveguides, Si waveguides, S-series glass, thin-film LiNbO3, and Si... x N y waveguide or Si x C y Waveguides, etc.

[0098] Finally, the second filter 3046 filters out the signal light and pump light, leaving the idler light. The idler light is the wavelength-converted signal light; it can be understood that the wavelength of the second signal light is λ. S After wavelength conversion, the wavelength of the third signal light is λ. I .

[0099] Understandably, taking the generation of idler light using four-wave mixing as an example, four-wave mixing refers to the generation of a new light wave by mixing two or three wavelengths of light. The pump light is used to provide energy; after mixing the signal light and the pump light, part of the pump light's energy is converted into a new light wave (idle light). The pump light (e.g., with a wavelength of λ) P ), signal light (e.g., wavelength λ) S ) and idler light (such as light with wavelength λ) I The wavelength of λ satisfies the following relationship: S +λ I =2λ PIn this way, the wavelength converter can control the wavelength position of the generated idler light by controlling the wavelength position of the pump light. Simultaneously, by controlling the power of the pump light, the power of the idler light can be controlled. Finally, the idler light is filtered out by a second filter; this idler light becomes the third signal light after wavelength conversion. Thus, a single wavelength converter can achieve wavelength conversion and power adjustment for one signal light. In this example, multiple wavelength converters operate independently without affecting each other. The power distribution detector selectively controls some or all of the wavelength converters through feedback control signals. If the wavelength of a certain second signal light does not need adjustment, the pump laser of the corresponding wavelength converter can be turned off, meaning the wavelength of that second signal light does not need adjustment, providing flexibility.

[0100] The wavelength conversion method in this example has a response rate on the femtosecond scale and is transparent to the transmitted data format, enabling wavelength conversion and power adjustment for signal light with various modulation formats. For example, the wavelength conversion method is applicable not only to modulation formats such as on-off keying (OOK) and pulse amplitude modulation (PAM), which load modulation information onto the pulse intensity, but also to modulation formats such as phase shift keying (PSK), which load modulation information onto the phase, and quadrature amplitude modulation (QAM), a higher-order modulation format that loads modulation information onto both the phase and pulse intensity.

[0101] 1) The principle of transferring the modulation information of the signal light (such as OOK or PAM) loaded onto the pulse intensity to the idler light is as follows:

[0102] For example, during wavelength conversion, the input pump light remains continuous, the second signal light carries an OOK or PAM signal, and the converted idler light also carries an OOK or PAM signal, with the pulse intensity of the idler light being proportional to the pulse intensity of the input signal light. For an example, please refer to [link to example]. Figure 7A As shown, the second signal light carries the binary information "11010110011". Here, "1" corresponds to "pulse intensity". After wavelength transformation, in the corresponding time unit (e.g., t1), the idler light also has pulse intensity, and the idler light acquires the information "1". "0" corresponds to "no pulse intensity". After wavelength transformation, in the corresponding time unit (e.g., t2), the idler light also has no pulse intensity, and the idler light acquires the information "0". Ultimately, the idler light carries the same binary information "11010110011" as the second signal light.

[0103] 2) The principle of transferring the modulation information of the signal light (such as QPSK or QAM) with modulation format loaded in the phase to the idler light is as follows:

[0104] During wavelength conversion, the input pump light remains continuous. The second signal light carries a QPSK or QAM signal, and the converted idler light also carries a QPSK or QAM signal. Furthermore, the phase information of the idler light is conjugate to the phase information of the second signal light, and the pulse intensity of the idler light is proportional to the pulse intensity of the signal light. For an example, please refer to [link to example]. Figure 7B As shown, the QPSK signal carries phase information. After wavelength conversion, the phase information of the second signal light is transferred to the idler light, and the phase information of the idler light at this time is... Therefore, the wavelength conversion method in this example has a response rate on the femtosecond scale and is transparent to the transmitted data format. It can realize wavelength conversion and power adjustment of signal light with various modulation formats and has a wide range of applications.

[0105] In this application, all-optical wavelength conversion technology is used to obtain the power spectra of multiple second signal beams by detecting their power spectra. Then, based on the mechanism of all-optical wavelength conversion, the wavelength position and power of the signal beams are selectively converted, ensuring that the power of the short-wavelength signal beam is always greater than the power of the long-wavelength signal beam before the adjusted multiple third signal beams enter the next fiber segment. After the multiple third signal beams are transmitted through the fiber again, the SRS effect is used to reduce the power of the short-wavelength light and increase the power of the long-wavelength light, thereby achieving power flatness of the signal beams. In this application, the wavelength conversion and power control of multiple signal beams are adjusted based on the detected power spectra of the multiple second signal beams. In an optical transmission link, due to the different insertion losses of optical fibers and optical devices for each channel, and the influence of factors such as amplification or dropout at reconfigurable optical add-drop multiplexer (ROADM) sites, the slope of the power spectrum envelope of the signal beam before reaching the relay node may be one of four cases: k>0, k<0, k=0, or without a general pattern. The following describes the optical power spectra of the multiple second signal beams detected by the power distribution detector, and the adjustment method of the wavelength converter for the second signal beams.

[0106] In the first scenario, when the power distribution detector detects that the power spectrum of multiple second signal lights increases successively with wavelength, for example, please refer to [link to example]. Figure 8A As shown, the power distribution detector detects the power of multiple second signal lights as a function of wavelength (λ1<λ2<…<λ). n )Increases successively (P1) <P2<…<P nOptionally, the power spectrum of the multiple second signal beams can further satisfy: P1-P2=P2-P3=…=P n-1 -P n This means that the optical power difference between the signal lights in adjacent channels is the same. In this case, the slope k of the power spectrum envelope of the multiple second signal lights is greater than 0. When k > 0, the wavelength converter controls the wavelength position and power of the pump light, and generates idler light at the second wavelength based on the first wavelength of the second signal light and the first pump light. Here, the first wavelength is the wavelength to be converted, and the second wavelength is the target wavelength (i.e., the wavelength after conversion). The wavelength converter controls the wavelength position of the first pump light according to the first control signal, making the positions of the first and second wavelengths axially symmetrical in the target band, and controls the power of the first pump light so that the power of the idler light is the same as the power of the second signal light at the first wavelength. This results in the power of the multiple second signal lights being arranged from high to low in the short to long wavelength bands. In other words, short wavelengths are high-power signal lights, and long wavelengths are low-power signal lights.

[0107] For example:

[0108] The power levels of the multiple second signal beams detected by the power distribution detector are shown in Table 1 below:

[0109] Table 1

[0110] wavelength <![CDATA[λ1]]> <![CDATA[λ2]]> … <![CDATA[λ n-1 ]]> <![CDATA[λ n ]]> power <![CDATA[P1]]> <![CDATA[P2]]> … <![CDATA[P n-1 ]]> <![CDATA[P n ]]>

[0111] The wavelengths of the multiple secondary signal beams satisfy: λ1 < λ2 < … < λ n The power of the multiple second signal beams satisfies: P1 <P2<…<P n .

[0112] For example, for the first wavelength converter, if the first wavelength converter receives signal light with wavelength λ1 (first wavelength), the power of the signal light is P1, where P1 is the minimum of all powers, and the wavelength at the axisymmetric position of λ1 is λ. n (Second wavelength), therefore, the wavelength corresponding to P1 needs to be transformed from λ1 to λ. n .

[0113] The first wavelength converter controls the position of the pump light. If n is odd, the position of the pump light can be λ. (1+n) / 2 If n is even, then the position of the pump light can be λ. n / 2 and λ (n / 2)+1 The center wavelength. The first wavelength converter is at λ. n The position generates idler light (i.e., generates light with a wavelength of λ). nThe idler light is used to control the power of the pump light, so that the power of the idler light is P1. The first wavelength converter keeps the power of the received second signal light constant and changes the wavelength of the second signal light.

[0114] For example, consider a second wavelength converter that receives a second signal light with a wavelength of λ2 (the first wavelength). The power of this second signal light is P2, which is the second smallest of all powers. The wavelength at the axisymmetric position of λ2 is λ. n-1 (Second wavelength), therefore, the wavelength corresponding to P2 needs to be transformed from λ2 to λ. n-1 .

[0115] The second wavelength converter controls the position of the pump light at λ. n-1 The position generates idler light (i.e., generates light with a wavelength of λ). n-1 The idler light is used to control the power of the pump light, making the power of the idler light P2. The second wavelength converter keeps the power of the received second signal light constant and changes the wavelength of the second signal light to λ. n-1 .

[0116] The above examples illustrate the operation of two wavelength converters. For a detailed understanding of the operation of other wavelength converters, please refer to the examples above. These will not be elaborated upon here. For instance, the third wavelength converter transforms λ3 to λ... n-2 And so on. After each wavelength converter performs wavelength conversion on the signal light, the power of the multiple third signal lights output by the entire wavelength converter array is shown in Table 2 below:

[0117] Table 2

[0118] wavelength <![CDATA[λ1]]> <![CDATA[λ2]]> … <![CDATA[λ n-1 ]]> <![CDATA[λ n ]]> power <![CDATA[P n ]]> <![CDATA[P n-1 ]]> … <![CDATA[P2]]> <![CDATA[P1]]>

[0119] from Figure 8A As can be seen from Table 2 above, after wavelength conversion, the multiple second signal beams from λ1 to λ2... n In this example, when the power spectrum of the multiple second signal lights increases with wavelength, it is not necessary to change the power of the second signal lights. Only the wavelength of the second signal lights needs to be adjusted to transform the wavelength to an axisymmetric wavelength position. This allows the power of the multiple third signal lights to be arranged from high to low in the target wavelength band from short to long wavelength, thus achieving SRS compensation.

[0120] In the second scenario, when the powers of the multiple second signal lights detected by the power distribution detector are equal (P1 = P2 = ... = P...), the power distribution detector detects that the power of each signal is equal. n When k=0, a second control signal is generated.

[0121] In this scenario, the wavelength converter needs to control the power of the idler light by adjusting the power of the pump light. However, as the principle of wavelength conversion dictates, wavelength conversion also occurs during the process of controlling the power of the idler light. It can be understood that the idler light is newly generated light at a specific wavelength position, and the wavelength conversion and power adjustment of the second signal light are performed simultaneously. In this second scenario, since the power of all multiple second signal lights is equal, the position of one of the multiple second signal lights can be changed to any wavelength position. However, the target sequence position (i.e., the order of precedence) of this wavelength position within the target band must be recorded. The wavelength converter controls the wavelength position of the second pump light according to the second control signal, ensuring that the second wavelength position is at the target sequence position within the target band. The power of the second pump light is then controlled according to the target sequence position of the second wavelength to control the power of the idler light, ensuring that the power of the idler light is at the target sequence position in the power spectrum of the multiple third signal lights. Finally, the power spectrum of the multiple idler light (i.e. multiple third signal light) output by the wavelength converter array is arranged from high to low according to the wavelength.

[0122] For example:

[0123] Please see Figure 8B As shown in Table 1 above, the wavelengths of the multiple second signal beams satisfy: λ1 < λ2 < ... < λ n The power of the multiple second signal beams satisfies: P1 = P2 = ... = P n .

[0124] For the first wavelength converter, it receives a second signal light with wavelength λ1. Based on a second control signal, it generates idler light at position λ3. λ3 is the third position (or order) in the target band. Therefore, the first wavelength converter controls the power of the pump light so that the idler light's power ranks third in the power spectrum of the multiple third signal lights. This target position is merely an example; it can be any position. For instance, the first wavelength converter could also... n Position generates idler light, λ n If the target sequence position in the target band is the last position, then the first wavelength converter controls the power of the pump light so that the power of the idler light is in the last position (i.e., the nth position) in the power spectrum of the multiple third signal lights.

[0125] For example, regarding the second wavelength converter, it receives a second signal light with wavelength λ2. Based on a second control signal, it generates an idler light at position λ1. Since λ1 is the first position in the target wavelength band, the second wavelength converter controls the power of the pump light so that the idler light's power ranks first in the power spectrum of the multiple third signal lights. The above provides two examples of wavelength converter operation. For the specific operation of other wavelength converters, please refer to the above two examples for further understanding; they will not be elaborated upon here.

[0126] In this second case, when the slope k of the power spectrum envelope of the multiple second-channel optical signals is 0, that is, the power between channels is equal (P1 = P2 = ... = P...). n The wavelength converter array needs to redistribute power between channels. The control unit in the power distribution detector determines the specific wavelength position (i.e., target sequence position) that each signal light needs to be converted to, and the control unit determines the power conversion efficiency (e.g., E1, E2, ..., E...) based on this target sequence position. n The power conversion efficiency of the multiple third-signal optical signals can meet E1. <E2<…<E n The powers of the multiple third-signal optical signals are P1′, P2′, ..., P. n '. P1′=P1×E1; P2′=P2×E2;…;P n ′=P n ×E n The control unit determines the target sequence position of the wavelength after transformation of each second signal light, and then determines the power conversion efficiency based on this target sequence position. For example, taking the first wavelength converter mentioned above as an example, after receiving the second signal light with wavelength λ1 and performing wavelength transformation, the first wavelength converter transforms the wavelength to λ3. λ3 is the third position in the target band. Then, the power distribution detection unit determines E3 as the power conversion efficiency of the first wavelength converter. The first wavelength converter controls the power of the pump light so that the power of the idler light is P3′=P3×E3. That is, the wavelength controller can control the position and power of the pump light according to the target sequence position and power conversion efficiency, thereby making the output multiple third signal lights sorted from high to low, i.e., P1′>P2′>…>P n ′.

[0127] Optionally, the wavelength converter controls the power of the pump light so that the power difference between signal light at adjacent wavelengths is the same, i.e., P1′-P2′=P2′-P3′=…=P n-1 ′-P nFinally, the power spectrum envelope slope k of the multiple third signal beams output by the wavelength converter array is less than 0. This ensures that after the multiple third signal beams re-enter the fiber, the SRS effect is used to reduce the power of short-wavelength light and increase the power of long-wavelength light, thereby achieving power flatness of the signal beams.

[0128] For the third scenario, please refer to [link / reference]. Figure 8C As shown, when the power distribution detector detects that the power distribution of multiple second signal lights is disordered, it generates a third control signal.

[0129] When the power of the second signal light at the first wavelength is arranged in descending order in the power spectrum and is located at the Xth position, the wavelength converter controls the wavelength position of the third pump light according to the third control signal to generate idler light at the second wavelength, wherein the second wavelength is the wavelength located at the Xth position in the target band.

[0130] The power of the second signal light at each wavelength is shown in Table 3 below:

[0131] Table 3

[0132] wavelength <![CDATA[λ1]]> <![CDATA[λ2]]> <![CDATA[λ3]]> … <![CDATA[λ n-1 ]]> <![CDATA[λ n ]]> power <![CDATA[P1]]> <![CDATA[P2]]> <![CDATA[P3]]> … <![CDATA[P n-1 ]]> <![CDATA[P n ]]> Power sequence 3 1 n … 2 n-1

[0133] As shown in Table 3 above, the power of the second signal light with wavelength λ1 is P1, and P1 ranks third in the power spectrum of the multiple second signal lights (powers are arranged from largest to smallest). The power of the second signal light with wavelength λ2 is P2, and P2 ranks first in the power spectrum of the multiple second signal lights. The power of the second signal light with wavelength λ3 is P3, and P3 ranks nth in the power spectrum of the multiple second signal lights, and so on.

[0134] For example:

[0135] For the first wavelength converter, the first wavelength converter receives a second signal light with a wavelength of λ1 and a power of P1. P1 is in the third position in the power spectrum. The first wavelength converter generates idler light at the third wavelength position (i.e., λ3) according to the third position, that is, the wavelength of the second signal light is converted to λ3.

[0136] For the second wavelength converter, it receives a second signal light with wavelength λ2 and power P2. P2 is the first position in the power spectrum. The second wavelength converter then generates idler light at the first wavelength position (λ1) according to this first position, meaning it converts the wavelength of the second signal light to λ1. The above provides examples of two wavelength converters. For the specific operation of other wavelength converters, please refer to the above examples; they will not be elaborated upon here. The power spectra of the multiple third signal lights output by the wavelength converter array in the target band are shown in Table 4 below.

[0137] Table 4

[0138] wavelength λ1 λ2 λ3 … λn-1 λn power <![CDATA[P2]]> <![CDATA[P n-1 ]]> <![CDATA[P1]]> … <![CDATA[P n ]]> <![CDATA[P3]]> Power sequence 1 2 3 … n-1 n

[0139] Optional, please refer to Figure 8D As shown, the wavelength converter controls the power of the pump light to ensure that the power difference between idler light (i.e., the third signal light) at adjacent wavelengths is the same. The power spectra of the multiple third signals are: P1′, P2′, P2′, ..., P n-1 ′, P n And P1′-P2′=P2′-P3′=…=P n-1 ′-P n Where, P2′=P2×E1, P n-1 ′=P n-1 ×E2,…,P1′=P1×E n-1 P3′=P3×E n The power conversion efficiency of the multiple third-signal optical signals meets E1. <E2<…<E n Finally, the slope k of the power spectrum envelope of the multiple third signal beams output by the wavelength converter array is less than 0. In this example, the power difference between two adjacent third signal beams is the same, ensuring that the difference between two adjacent third signal beams is not too large. This guarantees that after the multiple third signal beams are transmitted through the fiber again, the SRS effect is used to reduce the power of short-wavelength light and increase the power of long-wavelength light, thereby achieving power flatness of the signal beams.

[0140] For the fourth scenario, please refer to [link / reference]. Figure 8E As shown, when the power distribution detector detects that the power of the multiple signal lights decreases successively with wavelength (i.e., the slope k of the power spectrum envelope is < 0), the power distribution detector generates a fourth control signal. The wavelengths of the multiple second signal lights satisfy: λ1 < λ2 < ... < λ n The power of the multiple second signal beams satisfies: P1>P2>…>P n Optional, P1-P2=P2-P3=…=P n-1 -P n .

[0141] The wavelength converter controls the pump light power to be 0 according to the fourth control signal. Since the power of the multiple second signal lights already meets the requirement of being arranged from high to low wavelength, wavelength conversion of the multiple second signal lights is not required. That is, the wavelength converter controls the pump laser to be turned off and does not process the multiple second signal lights.

[0142] In this example, the power distribution detector detects the power spectrum of multiple second signal lights and generates a feedback control signal based on the specific power spectrum. The wavelength converter dynamically and selectively performs wavelength conversion on the signal lights and controls the power of idler light based on different power spectrum conditions, so that the power distribution of the signal lights in all channels is arranged from high to low according to the wavelength (short wave to long wave), so that the power flatness between all channels is achieved after the third signal light enters the next fiber optic link for transmission.

[0143] In one application scenario, the SRS compensation device of this application is used in a C+L band coherent optical communication system. Please refer to [link / reference]. Figure 9 As shown, C-band and L-band transmitter arrays emit multiple wavelength signal lights in the C-band (1530-1560nm) and L-band (1565-1625nm), respectively. Then, a C-band optical amplifier amplifies the multiple wavelength signal lights, and an L-band optical amplifier amplifies the multiple wavelength signal lights. The amplified C-band and L-band signal lights are coupled into the transmission optical fiber by a wavelength division multiplexer. By adjusting the gain of the optical amplifiers and the gain flattening filter within them, it can be ensured that the power of the multiple wavelength signal lights at point A before entering the optical fiber is approximately equal (e.g., the power entering the fiber is 0dBm for both). When multiple wavelength signal lights are transmitted through the optical fiber link to point B, due to the SRS effect in the optical fiber, the power of the short-wave channel is transferred to the power of the long-wave channel. At point B, the power spectrum envelope of the entire C+L band signal light is tilted, and the slope of the power spectrum envelope k>0. The maximum power of all wavelength signal lights is -13dBm, the minimum power is -20dBm, and the power difference between the maximum and minimum power reaches 7dB.

[0144] The SRS compensation device is set between points B and C. The SRS compensation device receives the multiplexed first signal light. First, it separates the first signal light in the C-band and L-band into multiple second signal lights. The SRS compensation device controls the wavelength position of the pump light and selects the wavelength position of the pump light at the gap between the C-band and L-band (such as any position between 1560-1565). The SRS compensation device generates idler light according to the position of the pump light in order to complete the symmetrical transformation between the C-band and L-band.

[0145] The SRS compensation device converts the wavelengths of multiple second signal beams in the C-band to the L-band, and similarly converts the wavelengths of multiple second signal beams in the L-band to the C-band. Then, the wavelength-converted multiple third signal beams undergo combining. When the combined signal beam reaches point C, the power spectrum envelope slope of the entire C+L band signal beam is less than 0 (k < 0). At this point, the C+L band signal beam undergoes further transmission through a fiber optic link (…). Figure 9As shown in the diagram (from point C to point D), the SRS effect in the optical fiber reduces the power of the C-band signal light and increases the power of the L-band signal light. When the signal light reaches point D, the power spectrum of the C+L band signal light becomes flat. Following this process, the C+L band signal light will again pass through optical fiber, amplifier, optical fiber, amplifier, etc., before finally reaching the receiver. It is then split by a wavelength division multiplexer. The C-band signal is amplified and enters the C-band receiver array, where it is demodulated. The L-band signal is amplified and enters the L-band receiver array, where it is demodulated. Because the entire system compensates for the SRS effect at the relay nodes, the power spectrum of the signal light remains flat throughout the transmission process, avoiding the decrease in optical signal-to-noise ratio for short wavelengths and the enhancement of nonlinear effects for long wavelengths. This is of great significance for improving the performance of broadband optical transmission systems. Furthermore, the response rate of the all-optical wavelength conversion is on the femtosecond scale, avoiding channel damage. Moreover, the compensation device in this application greatly reduces costs compared to the traditional compensation method that involves adding a large number of Raman pump lasers.

[0146] This application also provides an SRS compensation method, which is applied to... Figure 3 The SRS compensation device in the corresponding embodiment includes an optical beam splitter, a power distribution detector, a wavelength division multiplexer, a wavelength converter array, and a wavelength division multiplexer. Please refer to [link to relevant documentation]. Figure 10 As shown, the method includes:

[0147] Step 1001: Receive the first signal light through an optical beam splitter, output a portion of the first signal light to a power distribution detector, and output the other portion of the first signal light to a wave demultiplexer.

[0148] Step 1002: The first signal light is separated into multiple second signal lights by a power distribution detector, and the power spectrum of the multiple second signal lights is detected; and a feedback control signal is generated based on the power spectrum.

[0149] For example, a power distribution detector includes a beam splitter, a photodetector array, and a control unit.

[0150] The first signal light is received by a beam splitter, the first signal light is separated into multiple second signal lights, and the multiple second signal lights are transmitted to the corresponding photodetectors respectively.

[0151] The second signal light is converted into an electrical signal by a photodetector and then transmitted to the control unit.

[0152] The control unit determines the power spectrum of the multiple second signal lights based on the electrical signal and generates a feedback control signal based on the power spectrum.

[0153] Step 1003: The first signal light is separated into multiple second signal lights by a wavelength demultiplexer, and the multiple second signal lights are transmitted to the corresponding wavelength converters respectively.

[0154] Steps 1002 and 1003 are not limited in timing; they can be executed synchronously.

[0155] Step 1004: The wavelength of the multiple second signal lights is changed by the wavelength converter array according to the feedback control signal to adjust the power spectrum of the multiple second signal lights, and the adjusted multiple third signal lights are output. The power of the multiple third signal lights is arranged from high to low in the target wavelength band from short wavelength to long wavelength.

[0156] The second signal light of the first wavelength is received by the wavelength converter. The wavelength position and power of the pump light are controlled according to the feedback control signal. The idler light is generated on the second wavelength according to the second signal light of the first wavelength and the pump light. The idler light is filtered out. The idler light is the third signal light.

[0157] In one possible implementation, when the power spectrum of the multiple second signal lights is detected by the power distribution detector to increase with wavelength, the power distribution detector generates a first control signal.

[0158] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0159] The wavelength converter controls the position of the pump light according to the first control signal, so that the positions of the first wavelength and the second wavelength are axially symmetrical in the target band; and controls the power of the pump light so that the power of the idler light is the same as the power of the second signal light of the first wavelength.

[0160] When the power spectrum of the multiple second signal lights is detected by the power distribution detector to increase with wavelength, a first control signal is generated.

[0161] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0162] The wavelength converter controls the position of the pump light according to the first control signal, so that the positions of the first wavelength and the second wavelength are axially symmetrical in the target band; and controls the power of the pump light so that the power of the idler light is the same as the power of the second signal light of the first wavelength.

[0163] In one possible implementation, when the power distribution detector detects that the power of the multiple signal lights is equal, the power distribution detector generates a second control signal;

[0164] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0165] The wavelength converter controls the wavelength position of the pump light according to the second control signal, so that the second wavelength position is located at the target sequence position in the target band; the power of the pump light is controlled according to the target sequence position of the second wavelength, so as to control the power of the idler light, so that the power of the idler light is located at the target sequence position in the power spectrum of the multiple third signal lights.

[0166] In one possible implementation, a third control signal is generated when the power of the second signal light of the first wavelength is detected by a power distribution detector and is located at the Xth position in the power spectrum in descending order.

[0167] The wavelength position and power of the pump light are controlled by a wavelength converter based on a feedback control signal, including:

[0168] The wavelength position of the pump light is controlled by the wavelength converter according to the third control signal, and idler light is generated at the second wavelength, which is the wavelength located at the Xth position in the target band.

[0169] The power of the pump light is controlled by the wavelength converter according to the Xth sequence position, so as to control the power of the idler light and make the power of the idler light located at the Xth sequence position in the power spectrum of the multiple third signal lights.

[0170] In one possible implementation, a fourth control signal is generated when the power of the multiple signal lights is detected by a power distribution detector as the power decreases with each wavelength.

[0171] The power of the pump light is controlled to be 0 by the wavelength converter according to the fourth control signal.

[0172] Step 1005: Combine multiple third-channel optical signals using a wavelength division multiplexer and output them.

[0173] In this embodiment, the SRS compensation device, through the cooperation of a power distribution detector and a wavelength converter array, enables the power distribution detector to detect the power spectrum of the signal light and generate a feedback control signal. This feedback control signal further controls the wavelength converter array to adjust the power spectrum of the signal light, ensuring that the power of the adjusted signal light is arranged from high to low across the target wavelength range from short to long wavelengths. This compensates for the SRS effect, ensuring that when the adjusted signal light re-enters the fiber, the SRS effect reduces the power of short-wavelength light and increases the power of long-wavelength light, thus achieving power flatness of the signal light. This application achieves SRS compensation for the optical communication system with fewer components, resulting in lower cost and suitability for large-scale use. Furthermore, the SRS device is deployed at the relay node, without adding extra deployment workload.

[0174] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the SRS compensation method described above can be referred to the corresponding process in the aforementioned SRS compensation device embodiments, and will not be repeated here.

[0175] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A stimulated Raman scattering compensation device, characterized in that, include: Optical beam splitter, power distribution detector, wavelength demultiplexer, wavelength converter array and wavelength division multiplexer; The optical beam splitter is used to receive the first signal light, output a portion of the first signal light to the power distribution detector, and output another portion of the first signal light to the wave demultiplexer. The power distribution detector is used to separate the first signal light into multiple second signal lights and detect the power spectrum of the multiple second signal lights; And a feedback control signal is generated based on the power spectrum; The wavelength demultiplexer is used to separate the first signal light into multiple second signal lights, and transmit the multiple second signal lights to the corresponding wavelength converters respectively. The wavelength converter array is used to convert the wavelengths of multiple second signal lights according to the feedback control signal, so as to adjust the power spectrum of the multiple second signal lights and output the adjusted multiple third signal lights. The power of the multiple third signal lights is arranged from high to low in the target band from short wavelength to long wavelength. The wavelength division multiplexer is used to synthesize the multiple third signal optical signals and output them.

2. The apparatus according to claim 1, characterized in that, The wavelength converter is also used to receive a second signal light of a first wavelength, control the wavelength position and power of the pump light according to the feedback control signal, and generate idler light at a second wavelength according to the second signal light of the first wavelength and the pump light, and filter out the idler light; the idler light is the third signal light.

3. The apparatus according to claim 2, characterized in that, The power distribution detector is also used to generate a first control signal when the power spectrum of the multiple second signal lights is detected to increase with wavelength. The wavelength converter is further configured to control the wavelength position of the pump light according to the first control signal, so that the position of the first wavelength and the position of the second wavelength are axially symmetrical in the target band; and to control the power of the pump light so that the power of the idler light is the same as the power of the second signal light of the first wavelength.

4. The apparatus according to claim 2, characterized in that, The power distribution detector is also used to generate a second control signal when it detects that the power of the multiple second signal lights is equal; The wavelength converter is further configured to control the wavelength position of the pump light according to the second control signal, so that the second wavelength position is located at the target sequence position in the target band; and to control the power of the pump light according to the target sequence position of the second wavelength, so as to control the power of the idler light, so that the power of the idler light is located at the target sequence position in the power spectrum of the multiple third signal lights.

5. The apparatus according to claim 2, characterized in that, The power distribution detector is further configured to generate a third control signal when the power of the second signal light of the first wavelength is detected to be located at the Xth position in the power spectrum in descending order. The wavelength converter is also used to control the wavelength position of the pump light according to the third control signal, and generate idler light on the second wavelength, wherein the second wavelength is the wavelength located at the Xth position in the target band.

6. The apparatus according to claim 5, characterized in that, The wavelength converter is further configured to control the power of the pump light according to the Xth sequence position, so as to control the power of the idler light, and make the power of the idler light located at the Xth sequence position in the power spectrum of the multiple third signal lights.

7. The apparatus according to claim 2, characterized in that, The power distribution detector is also used to generate a fourth control signal when the power of the detected multi-channel signal light decreases successively with wavelength; The wavelength converter is also used to control the power of the pump light to be 0 according to the fourth control signal.

8. The apparatus according to any one of claims 1-6, characterized in that, The power distribution detector includes a beam splitter, a photodetector array, and a control unit; The beam splitter is used to receive the first signal light, split the first signal light into the multiple second signal lights, and transmit the multiple second signal lights to the corresponding photodetectors respectively. The photodetector is used to convert the second signal light into an electrical signal and transmit the electrical signal to the control unit; The control unit is configured to determine the power spectrum of the multiple second signal lights based on the electrical signal, and generate the feedback control signal based on the power spectrum.

9. The apparatus according to any one of claims 1-6, characterized in that, The power difference between two adjacent third signal beams in the multi-channel third signal beam is the same.

10. The apparatus according to any one of claims 1-6, characterized in that, The target bands include the C-band and the L-band.

11. A stimulated Raman scattering compensation method, characterized in that, The method is applied to a stimulated Raman scattering compensation device, which includes: an optical beam splitter, a power distribution detector, a wavelength division multiplexer, a wavelength converter array, and a wavelength division multiplexer; the method includes: The optical beam splitter receives the first signal light, outputs a portion of the first signal light to the power distribution detector, and outputs another portion of the first signal light to the wave demultiplexer. The first signal light is separated into multiple second signal lights by the power distribution detector, and the power spectrum of the multiple second signal lights is detected; and a feedback control signal is generated based on the power spectrum. The first signal light is separated into multiple second signal lights by the wavelength demultiplexer, and the multiple second signal lights are transmitted to the corresponding wavelength converters respectively. The wavelength converter array converts the wavelengths of multiple second signal lights according to the feedback control signal to adjust the power spectrum of the multiple second signal lights and outputs adjusted multiple third signal lights. The power of the multiple third signal lights is arranged from high to low in the target wavelength band from short wavelength to long wavelength. The wavelength division multiplexer synthesizes the multiplexed third signal light and outputs it.

12. The method according to claim 11, characterized in that, The step of converting the wavelengths of multiple second signal lights according to the feedback control signal via the wavelength converter array includes: The wavelength converter receives a second signal light of a first wavelength, controls the wavelength position and power of the pump light according to the feedback control signal, and generates idler light at a second wavelength based on the second signal light of the first wavelength and the pump light, and filters out the idler light; the idler light is the third signal light.

13. The method according to claim 12, characterized in that, The step of separating the first signal light into multiple second signal lights using the power distribution detector, detecting the power spectrum of the multiple second signal lights, and generating a feedback control signal based on the power spectrum includes: When the power spectrum of the multiple second signal lights is detected by the power distribution detector to increase with wavelength, a first control signal is generated. The step of controlling the wavelength position and power of the pump light through the wavelength converter according to the feedback control signal includes: The wavelength converter controls the wavelength position of the pump light according to the first control signal, so that the positions of the first wavelength and the second wavelength are axially symmetrical in the target band; and controls the power of the pump light so that the power of the idler light is the same as the power of the second signal light of the first wavelength.

14. The method according to claim 12, characterized in that, The step of separating the first signal light into multiple second signal lights using the power distribution detector, detecting the power spectrum of the multiple second signal lights, and generating a feedback control signal based on the power spectrum includes: When the power distribution detector detects that the power of the multiple second signal lights is equal, a second control signal is generated; The step of controlling the wavelength position and power of the pump light through the wavelength converter according to the feedback control signal includes: The wavelength converter controls the wavelength position of the pump light according to the second control signal, so that the second wavelength position is located at the target sequence position in the target band; the power of the pump light is controlled according to the target sequence position of the second wavelength, so as to control the power of the idler light, so that the power of the idler light is located at the target sequence position in the power spectrum of the multiple third signal lights.

15. The method according to claim 12, characterized in that, The step of separating the first signal light into multiple second signal lights using the power distribution detector, detecting the power spectrum of the multiple second signal lights, and generating a feedback control signal based on the power spectrum includes: When the power of the second signal light at the first wavelength is detected by the power distribution detector and is located at the Xth position in the power spectrum in descending order, a third control signal is generated. The step of controlling the wavelength position and power of the pump light through the wavelength converter according to the feedback control signal includes: The wavelength converter controls the wavelength position of the pump light according to the third control signal to generate idler light at the second wavelength, which is the wavelength located at the Xth position in the target band.

16. The method according to claim 15, characterized in that, The method further includes: The power of the pump light is controlled by the wavelength converter according to the Xth sequence position, so as to control the power of the idler light and make the power of the idler light located at the Xth sequence position in the power spectrum of the multiple third signal lights.

17. The method according to claim 12, characterized in that, The step of separating the first signal light into multiple second signal lights using the power distribution detector, detecting the power spectrum of the multiple second signal lights, and generating a feedback control signal based on the power spectrum includes: When the power distribution detector detects that the power of the multi-channel signal light decreases successively with wavelength, a fourth control signal is generated. The step of controlling the wavelength position and power of the pump light through the wavelength converter according to the feedback control signal includes: The wavelength converter is also used to control the power of the pump light to be 0 according to the fourth control signal.

18. The method according to any one of claims 11-16, characterized in that, The power distribution detector includes a beam splitter, a photodetector array, and a control unit; the first signal light is separated into multiple second signal lights by the power distribution detector, and the power spectrum of the multiple second signal lights is detected. And generate a feedback control signal based on the power spectrum, including: The first signal light is received by the beam splitter, the first signal light is separated into multiple second signal lights, and the multiple second signal lights are transmitted to the corresponding photodetectors respectively. The photodetector converts the second signal light into an electrical signal, and the electrical signal is transmitted to the control unit. The control unit determines the power spectrum of the multiple second signal lights based on the electrical signal, and generates the feedback control signal based on the power spectrum.

19. The method according to any one of claims 11-16, characterized in that, The power difference between any two adjacent third signal beams in the multi-channel third signal beam is the same.

20. The method according to any one of claims 11-16, characterized in that, The target bands include the C-band and the L-band.

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