Polarization Compensator for Coherent Receiver Synchronization
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Solution Overview
Problem
In polarization multiplexing coherent receivers, synchronization stability of optical signals is compromised due to impairment from mixing of x-path and y-path signals during training sequence correlation, leading to incorrect synchronization and reduced stability.
Innovation Solution
The method involves performing polarization compensation on first-path and second-path electrical signals using updated filter coefficients, followed by synchronization of x-path and y-path training sequences, and rectification of polarization swapping if detected, to separate and stabilize the optical signals during synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If x-path and y-path optical signals are correlated with training sequences directly after dispersion compensation, then synchronization can be performed, but the mixed signals cause impairment leading to unobvious or multiple peaks and incorrect synchronization
Solution Approach 1:
The patent segments the optical signals by separating x-path and y-path signals through polarization beam splitters before correlation processing. This segmentation prevents mixing of polarization states during the critical correlation operation, allowing each path to be synchronized independently with its corresponding training sequence, thereby eliminating the peak ambiguity problem
Solution Approach 2:
The patent performs preliminary polarization separation and signal routing before the correlation operation. By pre-configuring the signal paths through polarization beam splitters and directing x-path signals to correlate with x-path training sequences and y-path signals to correlate with y-path training sequences, the system establishes correct synchronization conditions before the actual correlation peak detection occurs
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
This approach effectively improves synchronization stability by preventing impairment from mixed optical signals, ensuring accurate synchronization and enhancing the reliability of optical signal processing.
Implementation Method 1
performing, by a frequency mixer, frequency mixing on received input optical signals
Implementation Method 2
performing, by a photoelectric detector, photoelectric detection on optical signals output by the frequency mixer
Data Source
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AI summary
A method and an apparatus for processing optical signals are provided, where the method for processing optical signals includes: performing frequency mixing, photoelectric detection, analog/digital conversion, and dispersion compensation on received input optical signals, and then obtaining first-path polarization multiplexing optical signals and second-path polarization multiplexing optical signals; performing an initialization update process on filter coefficients, and performing polarization compensation on the first-path polarization multiplexing optical signals and the second-path polarization multiplexing optical signals by using the filter coefficients on which the initialization update is performed, to obtain initialized x-path optical signals and initialized y-path optical signals; synchronizing preset x-path training sequences and y-path training sequences by using the initialized x-path optical signals and the initialized y-path optical signals; and if a synchronization result indicates that polarization cross occurs, rectifying the polarization cross.