Signal power adaptive hierarchical based parallel fiber amplifier channel equalization system

Abstract

The application discloses a parallel optical fiber amplifier channel equalization system based on signal power adaptive grading, and is characterized in that: the system further comprises a power detection and grading module arranged in front of the parallel amplifier and used for detecting the input optical signal in real time and dividing the optical signal into several power grades based on a preset or adaptive threshold, and a signal distribution and merging module used for guiding the optical signals of different power grades divided to corresponding parallel amplifier paths and merging the optical signals output by each path after the parallel amplifier completes amplification processing to realize channel power equalization; through power grading and differential amplification, the application reduces the difference value of the output power of each channel, realizes intelligent equalization of multi-channel optical signals, improves system gain flatness, effectively reduces the bit error rate caused by power imbalance, avoids the problems of gain saturation of high-power signals and insufficient gain of low-power signals, and improves channel capacity.

Description

Technical Field

[0001] This invention relates to the field of optical fiber communication technology, specifically to a parallel optical fiber amplifier channel equalization system based on adaptive signal power grading. Background Technology

[0002] With the rapid development of multidimensional multiplexing technologies such as spatial division multiplexing (SDM), mode division multiplexing (MDM), wavelength division multiplexing (WDM), and polarization multiplexing (PDM), the transmission capacity of optical communication systems has been significantly improved. However, existing optical amplifier technologies still face severe challenges in the amplification stage of multi-channel multiplexed signals. Most mainstream amplification structures currently employ a uniform gain configuration, failing to provide targeted compensation based on the power differences of each channel signal. This results in uneven gain between channels, severely impacting system performance. Although some research has attempted to implement independent amplification for each channel, this approach significantly increases system complexity and cost, and struggles to guarantee stability and reliability in large-scale integrated applications.

[0003] In actual transmission, uneven power distribution is a common problem in channel signals across different multiplexing dimensions. For example, in a modulus-division multiplexing system, the fundamental mode (such as LP) often exhibits uneven power distribution. 01 Signal power is typically high, while higher-order modes (such as LP) 11 LP 21 (e.g., wavelength division multiplexing) has relatively low power; in wavelength division multiplexing systems, different wavelength channels exhibit power differences due to the different loss spectrum characteristics of optical fibers; in polarization multiplexing systems, power imbalances often exist between different polarization states. Existing amplifier systems lack the ability to adaptively process these power distribution characteristics, leading to increased gain mismatch and crosstalk between channels, thus restricting further improvements in the overall transmission quality and capacity of the system.

[0004] Therefore, how to achieve adaptive hierarchical processing of the power differences of multi-channel signals in a single optical amplification platform, and complete efficient equalization amplification while maintaining the compactness of the system structure, has become a core technical problem that urgently needs to be solved in current multidimensional multiplexed optical communication systems. To this end, a parallel fiber amplifier channel equalization system based on adaptive signal power hierarchical processing is proposed. Summary of the Invention

[0005] The purpose of this invention is to solve the above problems by proposing a parallel fiber amplifier channel equalization system based on adaptive signal power grading.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a parallel fiber amplifier channel equalization system based on adaptive signal power grading, comprising an input end for receiving optical signals, a parallel amplifier for amplifying the input optical signals, and an output end for outputting the amplified optical signals. The system is characterized by further comprising a power detection and grading module disposed before the parallel amplifier for real-time power detection of the input optical signals and for dividing the optical signals into several power levels based on preset or adaptive thresholds; and a signal allocation and merging module for guiding the divided optical signals of different power levels to the corresponding parallel amplifier paths and, after the parallel amplifier completes amplification, multiplexing and merging the output optical signals from each path to achieve channel power equalization. The power detection and grading module divides the input optical signals into high-power signal paths, medium-power signal paths, and low-power signal paths. The power detection and grading module employs an adaptive threshold setting mechanism to dynamically adjust the power grading boundaries according to network conditions or application scenarios, and is linked with wavelength or mode mapping rules to achieve dynamic power and channel scheduling.

[0007] Preferably, the signal distribution and merging module includes a signal distribution unit disposed before the parallel amplifier for distributing different power levels to each path of the parallel amplifier, and a signal merging unit disposed after the parallel amplifier for merging the amplified optical signals.

[0008] Preferably, the signal distribution unit includes an optical switch or a demultiplexer; the signal combining unit includes a mode multiplexer, a wavelength multiplexer, a polarization beam combiner, or an optical coupler.

[0009] Preferably, the parallel amplifier includes a single-core parallel amplifier or a multi-core parallel amplifier. The single-core parallel amplifier adopts a differentiated parallel structure composed of multiple independent single-core erbium-doped optical fibers, and the multi-core parallel amplifier adopts a spatial multiplexing structure composed of a single multi-core optical fiber.

[0010] The beneficial effects of this invention are as follows: by classifying and amplifying power, the difference in output power of each channel is reduced, intelligent equalization of multi-channel optical signals is achieved, the system gain flatness is improved, the bit error rate caused by power imbalance is effectively reduced, and the problems of gain saturation of high-power signals and insufficient gain of low-power signals are avoided, thereby improving channel capacity.

[0011] By introducing a power multiplexing mechanism, the power domain is used as a new multiplexing dimension after space, wavelength, and polarization. It can be efficiently integrated with existing space division, wavelength division, mode division, and polarization multiplexing technologies. Without modifying the existing multiplexing architecture, it can achieve coordinated amplification of multi-dimensional signals through power and channel mapping mechanism, adapting to the upgrade requirements of current mainstream optical communication systems and covering more than 90% of multi-dimensional multiplexing scenarios. The system structure is flexible, supporting both single-core parallel and multi-core parallel modes, taking into account both performance optimization and integration requirements. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall system structure of the single-core parallel amplifier embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of the overall system structure of an embodiment of the multi-core parallel amplifier of the present invention;

[0014] Figure 3 This invention is a schematic diagram of signal allocation and merging.

[0015] Figure 4 This invention is a schematic diagram of power graded amplification of signals of different spatial modes in a single-core array configuration;

[0016] Figure 5 This invention is a schematic diagram of parallel hierarchical amplification of spatial mode signals in a multi-core parallel configuration.

[0017] Figure 6 This is a schematic diagram illustrating the application of the present invention in mode division multiplexing and wavelength division multiplexing systems. Detailed Implementation

[0018] Below we combine Figures 1-6 The parallel fiber amplifier channel equalization system based on adaptive signal power grading described in this invention will be further explained.

[0019] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0020] See appendix Figure 1 -Appendix Figure 6As shown, a parallel optical fiber amplifier channel equalization system based on signal power adaptive grading includes an input end for receiving an optical signal, a parallel amplifier for amplifying the input optical signal, and an output end for outputting the amplified optical signal. It is characterized in that: it further includes a power detection and grading module arranged before the parallel amplifier for performing real-time power detection on the input optical signal and dividing the optical signal into several power levels based on a preset or adaptive threshold, and a signal distribution and merging module for guiding the optical signals of different divided power levels to corresponding parallel amplifier paths and multiplexing and merging the optical signals output from each path after the parallel amplifier completes the amplification process to achieve channel power equalization; the power detection and grading module divides the input optical signal into a high-power signal path, a medium-power signal path, and a low-power signal path; the power detection and grading module adopts an adaptive threshold setting mechanism, dynamically adjusts the power grading boundary according to the network state or application scenario, and is linked with the wavelength or mode mapping rule to achieve dynamic scheduling of power and channels.

[0021] The power detection and grading module parallelly detects the power of the optical signals in each channel through a high-precision optical power detector, with a detection accuracy of up to ±0.1 dB and a response time less than 1 microsecond; in terms of grading processing, the module presets a set of power thresholds {T1, T2, …, T n}, and divides the input optical signal power value P_in into n + 1 power intervals: when P_in < T1, it is classified as the first-level power signal, applicable to the low-power signal path, such as high-order spatial modes LP 21 、LP 12 etc.; when T i ≤ P_in < T i+1 , it is classified as the i + 1-level power signal, applicable to the medium-power signal path, such as medium-order modes LP 11 or specific wavelength channels; when P_in ≥ T n , it is classified as the n + 1-level power signal, applicable to the high-power signal path, such as the fundamental mode LP 01 or the dominant wavelength channel; this module supports an adaptive threshold adjustment mechanism and can dynamically optimize the power grading boundary according to changes in network load, channel power distribution characteristics, and application scenario requirements to ensure the best match between the grading result and the actual channel characteristics. At the same time, the module also has the ability to associate and learn power and channel types, and can establish a mapping relationship between power levels and spatial modes, wavelength channels, and polarization states to provide intelligent support for subsequent signal distribution.

[0022] The three core modules—power detection and classification module, signal distribution and merging module, and parallel amplifier—are linked through a power and channel mapping mechanism, transforming the traditional unified gain amplification mode into a differentiated parallel amplification mode based on power levels. The system supports modular and cascaded expansion, and multiple power-classified parallel amplifiers can be combined to construct a high-capacity channel equalization system. It also supports the hybrid deployment of single-core and multi-core parallel amplifiers.

[0023] During system execution, the power detection and classification module performs parallel power detection on the input multi-channel optical signals, acquiring real-time power information for each channel. Based on preset or adaptive power thresholds, it classifies the channel signals into several power levels and identifies the channel type (spatial mode, wavelength, polarization state, etc.). The signal allocation and merging module's signal allocation unit, based on the power classification results and channel type information, uses appropriate multiplexing techniques to distribute signals of different power levels to the corresponding paths of parallel amplifiers. The allocation process considers the current load state and performance characteristics of the paths to ensure optimal signal-path matching. Each path of the parallel amplifier performs corresponding amplification processing according to its physical parameter configuration and the characteristics of the input optical signal. High-power signal paths receive moderate gain to avoid saturation, low-power signal paths receive high gain to enhance signal strength, and medium-power signal paths maintain balanced gain to optimize noise performance. The signal merging unit in the signal allocation and merging module, along with the output, merges the amplified signals from each path using appropriate multiplexing devices, achieving a unified output in spatial, wavelength, or polarization dimensions. The merging process maintains the orthogonality of each channel, ensuring power balance and transmission quality of the output signal.

[0024] The system supports closed-loop control mode, which continuously monitors the power distribution and transmission quality of the output signal, and dynamically adjusts the power threshold, allocation strategy and amplification parameters to achieve continuous optimization of system performance.

[0025] See appendix Figure 1 -Appendix Figure 3 As shown, the signal distribution and merging module includes a signal distribution unit disposed before the parallel amplifier for distributing different power levels to each path of the parallel amplifier, and a signal merging unit disposed after the parallel amplifier for merging the amplified optical signals; the signal distribution unit includes an optical switch or a demultiplexer; the signal merging unit includes a mode multiplexer, a wavelength multiplexer, a polarization beam combiner, or an optical coupler.

[0026] The signal distribution and merging module is responsible for signal routing and multiplexing. Based on power detection and classification results, this module accurately maps signals of different power levels to corresponding parallel amplification paths, and achieves multiplexing and merging of optical signals after amplification. In terms of optical signal distribution, the module employs multi-dimensional multiplexing technology to achieve intelligent signal routing.

[0027] For spatial multiplexing systems, the module uses a spatial optical switch matrix or mode multiplexer to convert spatial mode signals (LPS) of different power levels. 01 LP 11 LP 21 The module imports signals into corresponding amplification paths according to their power levels. For wavelength division multiplexing (WDM) systems, it utilizes tunable wavelength selection switches (WSS) or arrayed waveguide gratings (AWGs) to import wavelength channels of different power levels into matching amplification channels based on the power-wavelength mapping relationship. For polarization division multiplexing (PDM) systems, it uses polarization beamsplitters and polarization controllers to allocate TE and TM polarization state signals to corresponding paths according to their power levels. For multidimensional hybrid multiplexing systems, the module supports joint scheduling of the above multiplexing methods to achieve cross-dimensional power and channel collaborative allocation. Regarding signal combining, after the signals in each path have been amplified, the module achieves unified signal output through corresponding multiplexing devices. Spatial dimension combining uses mode multiplexers or spatial beam combiners, wavelength dimension combining uses wavelength division multiplexers or spectral synthesizers, and polarization dimension combining uses polarization beam combiners. The module ensures that the combined signals maintain orthogonality in the corresponding multiplexing dimensions, with crosstalk between channels less than -40dB, achieving high-quality balanced output. The module supports fast switching and real-time scheduling, with signal allocation response time down to the microsecond level, adapting to real-time power changes in dynamic network environments. Meanwhile, the module has path status monitoring and fault switching functions. When a certain amplification path fails, it can automatically redistribute the corresponding signal to the backup path to ensure the reliability and continuity of the system.

[0028] See appendix Figure 1 -Appendix Figure 5 As shown, the parallel amplifier includes a single-core parallel amplifier or a multi-core parallel amplifier. The single-core parallel amplifier adopts a differentiated parallel structure composed of multiple independent single-core erbium-doped optical fibers, while the multi-core parallel amplifier adopts a spatial multiplexing structure composed of a single multi-core optical fiber. The parallel amplifier is the core execution unit for realizing differentiated amplification, and the two different implementation methods are adapted to the needs of different application scenarios.

[0029] The single-core parallel amplifier described above has each amplification path configured with precise physical parameters to adapt to specific power levels and channel types, exhibiting high flexibility and scalability, and is suitable for complex scenarios requiring fine-grained processing for different channel types.

[0030] In terms of parameter configuration, the high-power signal path uses a shorter erbium-doped fiber length (typically 3-8 meters) and a lower erbium ion doping concentration (500-1000 ppm) to avoid gain saturation and reduce nonlinear effects; the low-power signal path uses a longer erbium-doped fiber length (typically 15-30 meters) and a higher erbium ion doping concentration (1500-3000 ppm) to achieve high-gain, low-noise amplification, with the noise figure controllable within the 3-4 dB range; the medium-power signal path uses a balanced parameter configuration (fiber length 8-15 meters, doping concentration 1000-1500 ppm) to ensure an optimal balance between gain flatness and noise performance. Each amplification path can be further optimized for matching specific power levels by adjusting fiber core geometry parameters (core diameter, numerical aperture), pump power configuration, and the spectral characteristics of the gain medium. The system supports N-channel parallel configuration, where N can be flexibly set according to the number of power levels and channel type, with a typical configuration of 4-8 channels, expandable to more than 16 channels. Each amplification path is driven by an independent pump laser, with pump wavelengths typically selected at 980nm or 1480nm, and pump power independently adjustable from 50mW to 500mW. The system is equipped with an intelligent pump control algorithm that automatically optimizes the pump power allocation for each path based on the input signal power and target gain, achieving optimal gain performance and power consumption control.

[0031] Multi-core parallel amplifiers significantly improve system integration through spatial multiplexing while reducing packaging complexity and cost. This approach is particularly suitable for high-capacity spatial multiplexing systems and applications with strict size requirements. The multi-core fiber employs an N-core structure design, with typical configurations including 4, 7, and 19 cores. The cores are arranged regularly in space (e.g., square, hexagonal, or circular arrays), with core spacing set within the 30-50μm range to ensure crosstalk between cores is less than -40dB while maintaining good space utilization. Each core corresponds to a specific power level and channel type, achieving directional optimization through differentiated physical parameter design. Regarding core differentiation, different cores employ different erbium ion doping concentrations, core geometry parameters, and mode field area configurations. For example, core 1 is designed to carry high-power fundamental mode signals and uses a larger mode field area (80-120μm). 2 ) and lower doping concentration; cores 2-4 are designed to carry medium-power high-order modes or specific wavelength channels, employing a moderate mode field area (60-80 μm) and lower doping concentration; 2 ) and balanced doping concentration; cores 5-7 are designed to carry low-power channels, employing a smaller mode field area (40-60 μm) and balanced doping concentration; 2This method utilizes dedicated fan-in / fan-out devices to achieve spatial separation and merging of signals. The input fan-in device precisely couples signals of different power levels to their corresponding fiber cores based on power detection results and channel mapping rules, with coupling loss controlled below 0.5dB. The output fan-out device spatially merges the amplified signals from each fiber core to form a unified multi-channel output, with insertion loss less than 1dB. The multi-core fiber employs a common pumping system, achieving simultaneous excitation of each fiber core through side pumping or end-face pumping. The pump light is evenly distributed to each fiber core through a specially designed coupling structure, ensuring that each fiber core receives pump power matching its power level. The system supports spatial distribution adjustment of pump power, achieving differentiated configuration of pump power for each fiber core by adjusting coupling parameters.

[0032] Example 1: Single-core parallel amplifier

[0033] This embodiment uses a single-core array to achieve differentiated amplification. The system includes a power detection and classification module, a signal distribution and merging module, and a parallel amplifier.

[0034] The power detection and classification module is connected to the input optical signal and performs power detection and classification on the input signal containing LP. 01 LP 11 LP 21 LP 12 Real-time power detection is performed on multi-channel optical signals with various spatial modes, and each spatial mode signal is divided into different levels according to power based on an adaptive threshold. At the same time, a mapping relationship between power level and spatial mode is established, and the pump laser of the amplifier array is used to determine the high-power signal path, medium-power signal path and low-power signal path.

[0035] The signal distribution unit in the signal distribution and merging module uses a spatial optical switch matrix to guide mode signals of different power levels into the corresponding single-core fiber amplification path according to the power classification results and mapping relationship; after the signal amplification is completed, the signal merging unit merges the signals of each path through a mode multiplexer or a spatial bundler.

[0036] The single-core parallel amplifier comprises multiple independent single-core erbium-doped fiber amplification paths, each with differentiated parameter configurations based on its corresponding power level: the high-power channel path uses 3-8 meters of erbium-doped fiber and 500-1000 ppm erbium ion doping concentration; the low-power channel path uses 15-30 meters of fiber and 1500-3000 ppm doping concentration; and the medium-power channel path uses 8-15 meters of fiber and 1000-1500 ppm doping concentration. Each path is driven by an independent 980nm or 1480nm pump laser, with the pump power automatically adjusted within the range of 50mW to 500mW based on the input signal power and target gain.

[0037] With the above configuration, this embodiment achieves adaptive channel equalization amplification based on power multiplexing, and realizes dynamic and parallel power equalization control for multi-channel spatial mode optical signals.

[0038] Example 2: Multi-core parallel amplifier array

[0039] The difference between this embodiment and the first embodiment is that the amplifier array is implemented in a multi-core parallel manner. The system also includes a power detection and classification module, a signal distribution and merging module, and an amplifier array.

[0040] The input optical signal contains LP 01 LP 11 LP 21 LP 12 LP 22 LP 33 The power detection and classification module uses an adaptive threshold setting mechanism to classify each mode into multiple levels according to its power characteristics and establish a mapping relationship between power and mode. This, in conjunction with the pumping system, determines the fiber core corresponding to each power level.

[0041] The signal distribution unit in the signal distribution and merging module uses a fan-in device to accurately couple signals of different power levels to the corresponding fiber cores of the multi-core optical fiber according to the power detection results and mapping rules, with coupling loss controlled below 0.5dB. The signal merging unit uses a fan-out device to spatially merge the amplified signals from each fiber core, with insertion loss less than 1dB, forming a unified multi-channel output.

[0042] The multi-core parallel amplifier array employs a multi-core fiber structure with seven cores arranged in a hexagonal array, with a core spacing of 30-50 μm. Each core is designed differently according to its corresponding power level: cores carrying high-power fundamental mode signals are 80-120 μm in diameter. 2 High mode field area and low erbium ion doping concentration; the fiber core carrying medium-power signals uses 60-80μm 2 The mode field area and balanced doping concentration; the fiber core carrying low-power signals uses 40-60μm 2 The multi-core fiber features a large mode field area and a high doping concentration. It employs a side-pumped common-pump system, where the pump light is uniformly distributed to each core through a special coupling structure, ensuring that each core receives matched pump power.

[0043] This embodiment significantly improves system integration and reduces packaging complexity and cost while maintaining the power reuse mechanism, making it suitable for high-capacity space-division multiplexing systems and applications with strict size requirements.

[0044] Example 3: Application of Hybrid Multiplexing System

[0045] This embodiment demonstrates the application of the system in a hybrid mode division multiplexing and wavelength division multiplexing system. The system adopts a multi-core fiber structure and can flexibly switch between mode division multiplexing and wavelength division multiplexing modes according to application requirements.

[0046] Modular multiplexing mode: Multiple fiber cores correspond to LPs respectively. 01 LP 11 LP 12 Different spatial modes are represented. The power detection and classification module classifies modes according to their power characteristics, establishes a mapping relationship between power and mode, and dynamically adjusts the threshold. The signal distribution and merging module separates mode signals of different power levels and distributes them to the corresponding fiber cores through a mode demultiplexer; the signal merging unit merges the amplified signals and outputs them through a mode multiplexer. Each fiber core optimizes the mode field area and doping parameters for the corresponding mode type to adapt to the amplification requirements of different spatial modes.

[0047] Wavelength division multiplexing (WDM) mode: Multiple fiber cores correspond to different wavelength channels such as λ1+λ2, λ3, λ4, and λ5. The power detection and classification module analyzes the power distribution of each wavelength channel and establishes a wavelength-power mapping relationship. The signal allocation unit in the signal allocation and combining module allocates wavelength channels of different power levels to the corresponding fiber cores through wavelength selection switches or arrayed waveguide gratings; the signal combining unit combines and outputs the amplified wavelength signals through a WDM multiplexer. The gain spectrum of each fiber core is optimized for the target wavelength, and wavelength-selective gain is achieved by adjusting the doping concentration and fiber length.

[0048] The system is equipped with an intelligent mode switching mechanism. The power detection and classification module can automatically identify and switch operating modes according to the input signal type, and adjust the power classification threshold and channel mapping strategy accordingly. The signal allocation and merging module selects the appropriate multiplexing / demultiplexing devices according to the operating mode, realizing flexible switching between mode-division multiplexing and wavelength-division multiplexing. This embodiment demonstrates the effectiveness of using power level as a new multiplexing dimension in multidimensional multiplexed optical communication systems, providing a unified channel equalization solution for different types of multidimensional multiplexing systems.

[0049] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A parallel fiber optic amplifier channel equalization system based on adaptive signal power grading, comprising an input terminal for receiving optical signals, a parallel amplifier for amplifying the input optical signals, and an output terminal for outputting the amplified optical signals, characterized in that: The power detection and grading module is arranged in front of the parallel amplifier and is used for real-time power detection of the input optical signal and grading of the optical signal based on a preset or adaptive threshold value, and the signal distribution and merging module is used for guiding the optical signal of different power levels to the corresponding parallel amplifier path and multiplexing and merging the optical signals output by each path after the parallel amplifier completes the amplification process to realize channel power equalization.

2. The signal power adaptive hierarchical equalization system for parallel fiber amplifier channels as claimed in claim 1, wherein The signal distribution and merging module includes a signal distribution unit arranged in front of the parallel amplifier and used for distributing different power levels to the parallel amplifier path, and a signal merging unit arranged behind the parallel amplifier and used for multiplexing and merging the amplified optical signals.

3. The signal power adaptive hierarchical equalization system for parallel fiber amplifier channels as claimed in claim 2, wherein The signal distribution unit includes an optical switch or a demultiplexer, and the signal merging unit includes a mode multiplexer, a wavelength multiplexer, a polarization beam combiner, a spatial beam combiner or an optical coupler.

4. The signal power adaptive hierarchical equalization system for parallel fiber amplifier channels of claim 1, wherein: The parallel amplifier includes a single-core parallel amplifier or a multi-core parallel amplifier, the single-core parallel amplifier adopts a differentiated parallel structure composed of multiple independent single-core erbium-doped optical fibers, and the multi-core parallel amplifier adopts a spatial multiplexing structure composed of a single multi-core optical fiber.

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