Coherent Optical Detection Phase Noise Interleaving
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Solution Overview
Problem
Coherent optical receivers face challenges in reducing cycle slip-induced bit errors in phase-modulated signals, as differential coherent detection techniques minimize errors but introduce noise penalties, limiting system range.
Innovation Solution
A method and system that involve receiving phase-modulated signals, identifying phase noise, resetting the phase of data symbols based on control symbols, interleaving data samples to spread errors, and performing forward error correction, all without differential encoding and decoding, thereby reducing error rates and avoiding noise penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If differential coherent detection techniques are used to minimize cycle slip-induced bit errors, then bit error rate is reduced, but noise penalty increases and system range is reduced
Solution Approach 1:
The patent segments the signal processing into distinct functional blocks: a differential detection block that processes pairs of consecutive symbols to minimize cycle slip errors, and a noise compensation block that separately handles noise penalty issues. This segmentation allows each block to optimize for its specific function without compromising overall system range.
Solution Approach 2:
The patent introduces an intermediary phase estimation and compensation mechanism that operates between the differential detection and the final decision-making process. This intermediary block estimates phase noise and compensates for it, thereby reducing the noise penalty while maintaining the error-minimizing benefits of differential detection.
2Measurement precision
If coherent processing with local oscillator is used to process optical signals, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts and removes the local oscillator component from the coherent processing chain, replacing it with digital signal processing techniques that achieve similar detection accuracy without requiring complex hardware synchronization. This extraction simplifies the device while maintaining measurement precision.
Solution Approach 2:
The patent substitutes the mechanical/optical local oscillator synchronization mechanism with digital signal processing algorithms. Instead of using hardware-based coherent mixing with a local oscillator, the system uses digital correlation and phase estimation techniques that achieve equivalent detection accuracy with reduced hardware complexity.
Data Source
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AI summary
A system is configured to receive a block of symbols, associated with a phase-modulated signal that includes data symbols that correspond to a payload associated with the signal, and control symbols; process the control symbols to identify an amount of phase noise associated with the control symbols; reset a phase, associated with each of the data symbols, based on the amount of phase noise and a reference phase; interleave the respective data samples, of each of the data symbols with other data samples, where the interleaved respective data samples cause errors, associated with the respective data samples, to be spread out among the other data samples and reduces an error rate relative to a prior data rate that existed before the interleaving; and perform forward error correction on the interleaved respective data samples.