Polarization Diversity Optical System Reducing Leak Light
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Solution Overview
Problem
In coherent optical communication systems, polarization diversity detection faces issues due to leak light interference, which degrades receiving sensitivity and precision in signal demodulation.
Innovation Solution
A polarization diversity optical system device that includes a polarization split unit and a light combining unit with a polarization rotation function, utilizing a polarization beam splitter or beam displacer to split and combine coherent lights into orthogonal polarization components, reducing leak light through a half-wave plate and optical 90-degree hybrid configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarization beam splitter is used to split and combine coherent lights in polarization diversity detection, then the signal light and local light can be separated into orthogonal polarization components, but incomplete polarization separation causes leak light that interferes with the signal and degrades demodulation precision
Solution Approach 1:
A polarization controller is introduced as an intermediary element between the polarization beam splitter and the detection system. This controller actively manages and adjusts the polarization state of the combined light, serving as a mediator to compensate for incomplete polarization separation and eliminate leak light interference, thereby improving demodulation precision without requiring perfect polarization beam splitting.
2Measurement precision
If polarization components are combined simultaneously after polarization split, then interference light can be generated with matched polarization directions, but incomplete polarization separation results in leak light that reduces receiving sensitivity
Solution Approach 1:
The system employs a polarization controller that provides feedback control over the polarization state of the combined light. By continuously monitoring and adjusting the polarization parameters, the system can compensate for leak light generated during the combination process, ensuring optimal receiving sensitivity and minimizing the harmful effects of incomplete polarization separation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces leak light interference, enhancing signal demodulation precision by minimizing errors in the output signal, allowing for stable and accurate signal detection.
Implementation Method 1
a signal light S0 having an arbitrary polarization state (p-polarization component S0p, s-polarization component S0s) and a local light L0 of 45-degree linear polarization (p-polarization component L0p, s-polarization component L0s) are input to a polarization beam splitter 930. The p-polarization components S0p and L0p of the respective lights are transmitted through the polarization beam splitter 930, and the s-polarization components S0s and L0s are reflected from the polarization beam splitter 930.
Implementation Method 2
A polarization diversity optical system device that includes a polarization split unit and a light combining unit with a polarization rotation function, utilizing a polarization beam splitter or beam displacer to split and combine coherent lights into orthogonal polarization components, reducing leak light through a half-wave plate and optical 90-degree hybrid configuration.
Data Source
AI summary
A polarization diversity optical system device includes: a polarization split unit that splits a first coherent light into a first split light and a second split light whose polarization components are orthogonal to each other, and splits a second coherent light into a third split light and a fourth split light whose polarization components are orthogonal to each other; and a light combining unit that combines the first split light with one of the third split light and the fourth split light, and combines the second split light with the other of the third split light and the fourth split light.