Coherent Optical Dispersion Compensation Using Span Segmentation
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Solution Overview
Problem
Current dispersion and nonlinearity compensation methods in coherent optical communication systems face high calculation complexity and require dispersion compensation optical fibers, limiting their effectiveness and applicability, especially in high-speed systems like 16QAM format polarization multiplexing wavelength division multiplexing systems.
Innovation Solution
The method divides the optical fiber into N equal spans, performing dispersion compensation in each span followed by nonlinearity compensation using weighted summation of powers from 2k+1 sampling points of X and Y polarization states, where the weighted coefficient is inversely proportional to the distance from the current sampling point, reducing the need for dispersion compensation optical fibers and lowering calculation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional dispersion and nonlinearity compensation methods are used, then compensation precision can be achieved, but calculation complexity becomes excessively high
Solution Approach 1:
The patent divides the optical fiber into N equal spans, where N is a positive integer. Each span is processed independently through dispersion compensation followed by nonlinearity compensation. This segmentation reduces the overall calculation complexity by breaking down the complex compensation task into smaller, manageable units while maintaining compensation precision across the entire fiber length.
Solution Approach 2:
The patent applies different compensation strategies to different spans based on their specific characteristics. Each span undergoes dispersion compensation using a dispersion compensation operator, followed by nonlinearity compensation using weighted summation of powers from 2k+1 sampling points. This localized approach allows optimization of compensation precision in each span while controlling overall calculation complexity.
2Measurement precision
If dispersion compensation optical fibers are used, then dispersion can be compensated, but hardware complexity and cost increase
Solution Approach 1:
The patent replaces physical dispersion compensation optical fibers with a digital signal processing approach. Instead of using additional optical components and fibers to compensate for dispersion, the system uses a dispersion compensation operator applied in the digital domain during signal processing. This substitution eliminates the need for complex hardware while achieving the same compensation effect.
Solution Approach 2:
The patent creates a virtual copy of the dispersion compensation function through mathematical operators rather than physical fibers. The dispersion compensation operator acts as a digital replica that performs the same function as physical compensation fibers would, but with significantly reduced hardware complexity and cost.
3Measurement precision
If the optical fiber is divided into more spans, then nonlinearity compensation precision improves, but calculation complexity increases
Solution Approach 1:
The patent introduces a dynamic adjustment mechanism where the number of spans N and the number of sampling points 2k+1 can be adjusted based on system requirements. The weighted summation uses k as a parameter that can be optimized to balance between compensation precision and calculation complexity. This dynamic flexibility allows the system to adapt to different transmission conditions while controlling computational resources.
Data Source
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AI summary
A dispersion and nonlinearity compensation method and system in a coherent optical communication system are provided. The method comprises: dividing a total length of an optical fiber into N steps with equal lengths, and performing dispersion compensation and then nonlinearity compensation in each step. The step of performing nonlinearity compensation in each step comprises: with a current sampling point being a center, performing sampling on respective 2k+1 sampling points of X and Y polarization states, calculating powers of 2(2k+1) sampling points, adding powers of sampling points at the same position on X and Y polarization states to obtain 2k+1 power values, performing weighted summation on the 2k+1 power values, then multiplying the weighted sum by a preset coefficient W to obtain a nonlinear phase angle of the current sampling point, and performing compensation according to the nonlinear phase angle, wherein, N and k are positive integers. In the technical solution according to the embodiment of the present invention, the mode of calculating the nonlinear phase angle is improved, and the calculation complexity is reduced.