Blind polarization demultiplexing by constructing a cost function for coherent optical PDM-OFDM

Area of Science:

• Optical communications
• Signal processing

Background:

• Polarization demultiplexing is crucial for coherent optical PDM-OFDM systems.
• Conventional methods often rely on training symbols, introducing overhead and complexity.

Purpose of the Study:

• To develop a training symbols-free polarization demultiplexing method for PDM-OFDM.
• To improve efficiency and reduce overhead in coherent optical systems.

Main Methods:

• Constructing a cost function (CCF-PDM) for polarization demultiplexing.
• Utilizing neighboring subcarrier information to initialize gradient algorithm parameters.
• Reducing iterations and preventing polarization swapping.

Main Results:

• Achieved comparable performance to training symbol-based methods.
• Demonstrated effectiveness in high-speed (66.6-Gb/s, 133.3-Gb/s) and long-haul transmissions (up to 5440 km).
• Showcased fast convergence and no overhead.

Conclusions:

• The CCF-PDM method is a viable, efficient alternative for polarization demultiplexing in PDM-OFDM.
• Applicable to various modulation formats and long-haul scenarios.
• Offers significant advantages in terms of speed and overhead reduction.