Self-Phase Modulation Noise Calculation Using Adjacent Signal Powers
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Solution Overview
Problem
Current methods for calculating self-phase modulation noise in optical fiber transmission links require fine granularity of sub-spans to ensure precision, leading to increased complexity and hardware requirements due to the need to account for dispersion accumulation across each sub-span.
Innovation Solution
The apparatus calculates self-phase modulation noise by combining signal powers at multiple sampling periods, allowing for a larger granularity of sub-spans and reducing calculation complexity by using weighted averaging of signal powers at adjacent instants to account for dispersion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fine granularity of sub-spans is used to calculate self-phase modulation noise, then calculation precision is improved, but device complexity increases
Solution Approach 1:
The patent combines signal powers from multiple sampling periods (current and adjacent sampling instants) to calculate self-phase modulation noise. Instead of processing each fine-grained sub-span separately, the method merges the signal power information across multiple sampling points, allowing for larger sub-span granularity while maintaining calculation precision and reducing device complexity
Solution Approach 2:
The patent dynamically adjusts the granularity of sub-spans by using signal powers from multiple sampling periods. The calculation adapts to the signal characteristics by incorporating adjacent sampling instants, enabling the system to maintain precision without requiring fixed fine granularity, thus reducing hardware complexity
2Measurement precision
If fine granularity of sub-spans is used to calculate self-phase modulation noise, then calculation precision is improved, but calculation complexity increases
Solution Approach 1:
The patent combines signal powers from multiple sampling periods (current and adjacent sampling instants) to calculate self-phase modulation noise. Instead of processing each fine-grained sub-span separately, the method merges the signal power information across multiple sampling points, allowing for larger sub-span granularity while maintaining calculation precision and reducing calculation complexity
Solution Approach 2:
The patent performs preliminary calculation of signal powers at multiple sampling instants (current and adjacent periods) before computing the self-phase modulation noise. This preliminary action allows the system to use pre-computed power values from adjacent sampling points, reducing the overall calculation complexity while maintaining precision
3Measurement precision
If fine granularity of sub-spans is used to account for dispersion accumulation, then measurement precision is improved, but quantity of hardware components increases
Solution Approach 1:
The patent combines signal powers from multiple sampling periods to calculate self-phase modulation noise, which reduces the need for multiple electric dispersion compensation modules. By merging information from adjacent sampling instants, the system achieves the same measurement precision with fewer hardware components
Solution Approach 2:
The patent makes the signal power calculation multi-functional by using powers from current and adjacent sampling instants for a single noise calculation. This universal approach allows one set of power measurements to serve multiple calculation purposes, reducing the quantity of dedicated hardware components needed
Data Source
AI summary
The present invention provides apparatus for self-phase modulation noise calculation, apparatus for self-phase modulation noise elimination and optical coherent receiver. The apparatus for calculation comprises: a signal receiver to receive an input signal; a calculator connected to the signal receiver to calculate a self-phase modulation noise at the current instant by using the signal powers of an input signal waveform at the current instant and at several sampling instants adjacent to the current instant. The embodiments of the present invention calculates the self-phase modulation noise at a certain instant by using the signal powers at a plurality of digital sampling periods before and after this instant, and when the apparatus is used to calculate the self-phase modulation noise of each of the sub-spans in an optical fiber transmission link, in case that the calculation precision is ensured, the granularity of the sub-spans may be reduced, thereby lowering the complexity of the calculation.