Optical Reception Device Phase Difference Detection PMD Compensation
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Solution Overview
Problem
Conventional digital coherent receivers face challenges in maintaining reception precision due to rapidly varying PMD-induced polarization fluctuations, which cause shifts in the optimal sampling timing between polarization components of a multiplexed signal, leading to degradation in reception quality.
Innovation Solution
An optical reception device that converts polarization multiplexed signals into electrical signals, performs A/D conversion, and detects phase differences between polarization components to compensate for distortions, using a phase difference output unit to adjust sampling timings and execute digital signal processing for optimal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional digital coherent reception scheme is used, then frequency/phase offset and polarization fluctuations can be compensated, but reception stability deteriorates due to rapid polarization mode dispersion variations
Solution Approach 1:
The patent implements dynamic adjustment of sampling timing for each polarization component based on real-time phase difference detection. The sampling timing is not fixed but continuously adapted to compensate for rapidly varying PMD conditions, allowing the system to maintain optimal reception despite changing polarization characteristics
Solution Approach 2:
The patent employs feedback mechanisms where the phase difference between polarization components is detected and used to adjust sampling timing. This closed-loop feedback allows the system to continuously monitor polarization state and automatically correct sampling timing to maintain reception stability under varying PMD conditions
2Measurement precision
If sampling timing is adjusted for one polarization component, then reception precision for that component improves, but reception precision for the other polarization component deteriorates due to coupled polarization fluctuations
Solution Approach 1:
The patent segments the sampling timing control into independent adjustments for each polarization component. Instead of using a unified sampling timing for both components, the system independently optimizes sampling timing for each polarization component based on its specific phase difference, thereby improving precision without creating coupled fluctuations
Solution Approach 2:
The patent applies local quality by customizing sampling timing parameters for each polarization component according to its specific characteristics. Each polarization component receives tailored sampling timing adjustment based on its individual phase difference measurement, rather than applying a uniform approach that would compromise precision for either component
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively compensates for polarization distortions caused by PMD, preventing degradation in reception precision even with rapidly varying DGD, ensuring stable high-speed optical communication.
Implementation Method 1
an electrical signal converter that converts, into electrical signals, respective polarization components of a polarization multiplexed signal forming an optical signal
Implementation Method 2
executing A/D conversion processing for the electrical signals output from the electrical signal converter
Data Source
AI summary
An optical reception device (10) includes an electrical signal converter (110) that converts an optical signal serving as an input polarization multiplexed signal into electrical signals of respective polarization components, a signal processor (120) that executes digital signal processing for digital signals generated by executing A/D conversion processing, and a phase difference output unit (130) that detects a phase difference generated between the polarization components of the optical signal based on the signals having undergone digital signal processing, and outputs information representing the phase difference. The signal processor (120) compensates for the distortion of the optical signal based on the information representing the phase difference. Even if rapidly varying PMD exists, the optical reception device prevents degradation of the reception precision by executing signal processing in optimal identification phases for the respective polarization components of a received polarization multiplexed signal.