Polarization Skew Estimation Using Adaptive Equalizer Coefficients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In coherent optical communication systems, polarization skew between in-phase and quadrature paths affects signal performance, and existing compensation methods are complex and costly, particularly for high baud rate high-order modulation formats.
Innovation Solution
An apparatus and method that estimates polarization skew using the coefficients of an adaptive equalizer, allowing for accurate and efficient calculation of polarization skew without the need for expensive measurement instruments, applicable to both production stage calibration and real-time monitoring in optical transmission systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If digital signal processing algorithms are used to compensate for polarization skew, then polarization skew compensation is achieved, but implementation complexity increases
Solution Approach 1:
The patent extracts only the necessary coefficients (a0, a1, b0, b1) from the adaptive equalizer that contain polarization skew information, separating them from the full set of equalizer coefficients. This extraction approach enables polarization skew estimation without requiring complex DSP algorithms to process the entire signal, thus reducing implementation complexity while maintaining compensation effectiveness
Solution Approach 2:
The patent uses existing adaptive equalizer coefficients (which are already computed for signal equalization) as a copy source to derive polarization skew information. Instead of implementing a separate complex measurement and compensation system, the invention copies and reuses the existing equalizer coefficients for the additional function of polarization skew estimation, significantly reducing system complexity
2Measurement precision
If expensive measurement instruments are used to measure polarization skew, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent enables the optical communication system to self-measure its own polarization skew using its existing adaptive equalizer coefficients, without requiring external expensive measurement instruments. The system uses its own operational data (the equalizer coefficients that are already being computed for signal processing) to derive polarization skew information, making the measurement process self-sufficient and cost-effective
Solution Approach 2:
The patent makes the adaptive equalizer coefficients serve multiple functions: their primary function for signal equalization and an additional function for polarization skew measurement. By enabling these coefficients to perform both functions simultaneously, the invention eliminates the need for separate dedicated measurement equipment, thereby reducing system cost while maintaining measurement capability
Data Source
AI summary
Embodiments of this disclosure provide an apparatus and method for estimating polarization skew. The method includes: acquiring a plurality of coefficients of an adaptive equalizer of a receiving device; the plurality of coefficients of the adaptive equalizer include at least polarization skew of a transmitting device and polarization skew of the receiving device; and calculating the polarization skew of the transmitting device and the polarization skew of the receiving device according to the plurality of coefficients of the adaptive equalizer.