Polarization Tracking Device Using Inverse Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current polarization tracking methods in optical fiber communication require complex calculations for updating tap coefficients, leading to increased circuit scale and mounting costs.
Innovation Solution
Polarization tracking is achieved by updating two real number parameters corresponding to a deflection angle in the Poincare sphere, using inverse rotation to maintain the Stokes parameter S1 at 0, thereby reducing calculation complexity and circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tap coefficients are updated using MIMO configuration with multiple real numbers, then polarization tracking accuracy is improved, but circuit scale and mounting cost increase
Solution Approach 1:
The patent extracts only the essential parameters needed for polarization tracking by identifying that two real number parameters (corresponding to deflection angles in the Poincare sphere) are sufficient to track polarization fluctuations. This extraction eliminates the need to process all six real numbers in full MIMO configuration, thereby reducing circuit complexity while maintaining tracking accuracy.
Solution Approach 2:
The patent changes the parameter representation from six real numbers to two real number parameters by transforming the polarization tracking problem into updating only the deflection angles in the Poincare sphere. This parameter reduction maintains the essential tracking functionality while significantly reducing the computational burden and circuit scale.
2Reliability
If six real number tap coefficients are updated simultaneously, then comprehensive polarization state tracking is achieved, but calculation complexity increases
Solution Approach 1:
The patent extracts the essential degrees of freedom for polarization tracking by identifying that only two parameters (deflection angles) are needed to describe the polarization state changes. This extraction reduces the calculation from updating six real numbers to updating only two, thereby reducing calculation complexity while maintaining tracking reliability.
Solution Approach 2:
The patent transforms the problem from updating six real number tap coefficients to updating two real number parameters representing deflection angles in the Poincare sphere. This parameter transformation maintains the ability to track comprehensive polarization states while significantly reducing the computational complexity.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A polarization tracking device that tracks polarization fluctuation of light transmitted through an optical fiber using a Stokes vector, includes: rotation angle updating means for expressing a fluctuation amount of the Stokes vector on a Poincare sphere in an xy plane perpendicular to a travelling direction of a light wave using a first angle and a second angle, the first angle being an angle between a direction of an optical electric field of the light wave and a y axis, and the second angle being a phase difference between a component of the optical electric field in a direction of the y axis and a component of the optical electric field in a direction of an x axis orthogonal to the y axis; and inverse rotation application means for rotating the Stokes vector using an inverse polarization rotation matrix expressed with the first angle and the second angle.