Demonstration of Alamouti coded 200-Gb/s/λ coherent PON downstream enabled by polar coded truncated probabilistic...

Area of Science:

• Optical Communications
• Information Theory
• Modulation Techniques

Background:

• Passive Optical Networks (PONs) are crucial for high-speed data transmission.
• Polarization fluctuations and power budget limitations impact PON performance.
• Advanced modulation formats are needed to meet increasing bandwidth demands.

Purpose of the Study:

• To investigate a simplified coherent PON downstream using polar coded many-to-one (MTO) mapping based truncated probabilistic shaped 64-ary quadrature amplitude modulation (PTPS-64QAM).
• To evaluate the performance of PTPS-64QAM against uniformly distributed modulation formats.
• To assess the feasibility of PTPS-64QAM for future very high-speed PONs.

Main Methods:

• Implementation of a 200-Gb/s/λ coherent PON downstream system.
• Employing polar coded MTO mapping based PTPS-64QAM.
• Utilizing an Alamouti encoder to mitigate polarization fluctuations.
• Experimental validation under optical-back-to-back (OBTB) and 20-km transmission conditions.

Main Results:

• PTPS-64QAM achieved a 32-dB power budget (Class C+) in OBTB, outperforming UD-32QAM and UD-64QAM by 3-dB and 5-dB, respectively.
• For 20-km transmissions, PTPS-64QAM reached a 29-dB power budget with 2-dB and 5-dB improvements over UD-32QAM and UD-64QAM.
• Demonstrated superior performance compared to uniformly distributed modulation formats.

Conclusions:

• PTPS-64QAM shows significant power budget advantages in high-speed PONs.
• The Alamouti encoder effectively mitigates polarization fluctuations.
• PTPS-64QAM is a promising candidate for future very high-speed PON applications.