Two-parameter-SOP and three-parameter-RSOP fiber channels: problem and solution for polarization demultiplexing using...

Area of Science:

• Optical Communications
• Signal Processing

Background:

• The 2-parameter model is commonly used to describe rotation of the state of polarization (RSOP) in fiber channels.
• This model is inadequate for accurately representing RSOP, leading to issues in polarization demultiplexing (PolDemux).

Purpose of the Study:

• To demonstrate the inadequacy of the 2-parameter RSOP model.
• To introduce a more accurate 3-parameter RSOP model for fiber channels.
• To propose a digital signal processing (DSP) scheme for tracking and equalizing time-varying RSOP.

Main Methods:

• Analysis of three common 2-parameter RSOP models.
• Development of a 3-parameter RSOP solution.
• Implementation of a DSP tracking and equalization scheme using the extended Kalman filter (EKF).

Main Results:

• The 2-parameter RSOP model fails to accurately represent fiber channel behavior, causing PolDemux problems.
• The proposed 3-parameter solution and EKF-based DSP scheme effectively address these issues.
• The scheme demonstrates universal applicability and good performance in time-varying RSOP scenarios.

Conclusions:

• A 3-parameter model is necessary for accurate RSOP description in fiber channels.
• The proposed EKF-based DSP scheme provides a robust solution for PolDemux challenges.
• This work improves optical signal processing for coherent receivers.