Optical Equalizer Coefficient Adjustment for Polarization Tap Alignment
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Solution Overview
Problem
In high-speed optical transmission systems, existing equalizers lack control over their coefficients, leading to instability due to unadjusted X-axis and Y-axis polarization coefficients, which can result in inter-symbol crosstalk and degraded system performance.
Innovation Solution
A method and device that adjust the coefficients of an equalizer by acquiring a Jones matrix, determining singularity characteristics, and performing singularity alteration to align the coefficients with the central position of taps, thereby improving system stability and filter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If both coefficients of X-axis and Y-axis polarizations are shifted in the same direction, then the equalizer can be implemented, but the center of the coefficients cannot be adjusted to the central position of taps, resulting in system instability
Solution Approach 1:
The patent segments the coefficient adjustment process into two independent parts: X-axis polarization coefficients and Y-axis polarization coefficients. Instead of shifting both coefficients in the same direction as conventional methods, the patent adjusts their centers independently to align with the central position of taps. This segmentation allows precise control over each polarization's coefficient center, resolving the contradiction between implementation ease and system stability.
Solution Approach 2:
The patent applies local quality by making the adjustment characteristic different for X-axis and Y-axis polarizations. Specifically, it calculates separate center positions for each polarization's coefficients and adjusts them differently to align with the tap center. This localized adjustment ensures that each polarization's coefficients are optimally positioned, improving system stability while maintaining implementation feasibility.
2Ease of operation
If no control is involved over the coefficient of the equalizer, then the equalizer can operate, but system stability is impacted due to unadjusted coefficients
Solution Approach 1:
The patent implements self-service by enabling the equalizer to automatically detect and adjust its own coefficient centers. The system calculates the center positions of X-axis and Y-axis polarization coefficients, compares them with the tap center position, and performs automatic adjustment when misalignment is detected. This self-adjusting mechanism maintains ease of operation while ensuring system stability through continuous coefficient optimization.
Solution Approach 2:
The patent incorporates feedback by continuously monitoring the center positions of the equalizer coefficients and using this information to drive adjustment decisions. The system calculates the deviation between coefficient centers and tap center, and feeds this deviation information back to the adjustment mechanism. This feedback loop ensures that coefficients remain properly aligned, maintaining system stability without complicating operation.
Data Source
AI summary
A jones matrix is obtained using coefficients of an equalizer; a parameter of the jones matrix is obtained; a coefficient of an X axis polarization state or a Y axis polarization state in the coefficients is adjusted using the parameter of the jones matrix when the coefficients have singularity characteristics, or energy corresponding to each coefficient of X or Y axis polarization state under each order of a filter in the equalizer is determined using two coefficients of an X or Y axis polarization state in the equalizer coefficients; and a central position of a coefficient tap of X or Y axis polarization state of the equalizer is adjusted using the energy corresponding to each coefficient of X or Y axis polarization state under each order of the filter when the coefficient tap of the X axis or Y axis polarization state of the equalizer deviates from the central position.