Coherent Receiver Phase Correction Using Analog I/Q Error Detection
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Solution Overview
Problem
Existing signal receivers face significant challenges in correcting phase errors between in-phase and quadrature components, leading to increased bit error rates and higher required optical signal-to-noise ratios due to manufacturing imperfections and temperature effects, which existing digital signal processor techniques have not adequately addressed.
Innovation Solution
A simplified phase error correction method using an optical hybrid with an adjustable phase control mechanism, incorporating an exclusive or-gate and integrator or a multiplier and low pass filter to derive a phase error signal, allowing for efficient detection and correction of phase errors with minimal circuitry and processing delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signal processor techniques are used to correct phase error, then phase error correction is achieved, but the system complexity and processing delay increase
Solution Approach 1:
The patent extracts the phase error correction function from complex digital signal processing and implements it through a dedicated analog circuit block within the optical hybrid. This separate phase correction block uses simple analog components (multipliers, adders, integrators) to perform correction without requiring complex DSP algorithms, thereby reducing overall system complexity while maintaining correction effectiveness
Solution Approach 2:
The patent replaces digital signal processing (computational approach) with an analog circuit implementation (physical approach). The phase correction is achieved through continuous analog signal manipulation using multipliers and integrators rather than discrete digital calculations, which reduces processing delay and simplifies the computational burden on the DSP
2Reliability
If digital signal processor techniques are used to correct phase error, then phase error correction is achieved, but the processing delay increases
Solution Approach 1:
The patent replaces digital signal processing (computational approach) with an analog circuit implementation (physical approach). The phase correction is achieved through continuous analog signal manipulation using multipliers and integrators rather than discrete digital calculations, which reduces processing delay and simplifies the computational burden on the DSP
Solution Approach 2:
The phase correction circuit operates continuously in parallel with the signal reception and demodulation processes. The correction factors are calculated and applied in real-time before the main signal processing stages, eliminating the need for post-processing correction and reducing overall processing delay
3Device complexity
If phase error is not corrected, then the system is simpler, but bit error rate increases and optical signal to noise ratio requirements increase
Solution Approach 1:
The patent extracts the phase error correction function from complex digital signal processing and implements it through a dedicated analog circuit block within the optical hybrid. This separate phase correction block uses simple analog components (multipliers, adders, integrators) to perform correction without requiring complex DSP algorithms, thereby reducing overall system complexity while maintaining correction effectiveness
Solution Approach 2:
The phase correction circuit uses the received signal itself to generate the correction factors. The circuit automatically detects phase errors from the incoming signal and adjusts the correction parameters in real-time without requiring external calibration or complex control systems, achieving self-correction with minimal additional complexity
Data Source
AI summary
A method and apparatus for correcting of phase errors in a coherent optical receiver are disclosed. Embodiments include a method for calculating a phase error between in-phase and quadrature-phase component signals, multiplying the phase error by one of the component signals and subtracting the result from the other component signal to output a corrected signal.