Polarization division multiplexing link using a high-speed lithium niobate automatic polarization demultiplexer

Area of Science:

• Photonics and Optical Communications
• Integrated Photonics
• Data Center Technology

Background:

• Polarization division multiplexing (PDM) is crucial for increasing optical communication capacity.
• Existing PDM systems often face challenges with polarization fluctuations and complex demultiplexing.
• Thin-film lithium niobate (TFLN) offers a promising platform for high-speed and compact photonic devices.

Purpose of the Study:

• To propose and experimentally demonstrate a novel PDM link.
• To integrate a dual-polarization TFLN modulator with an on-chip automatic polarization demultiplexer.
• To evaluate the performance of the PDM link under dynamic polarization conditions.

Main Methods:

• Utilized an integrated dual-polarization TFLN modulator for signal generation.
• Employed an on-chip automatic polarization demultiplexer for signal separation.
• Tested the system's tracking speed and bit error rate (BER) under various polarization scrambling rates (SR).

Main Results:

• Achieved an 80-Gb/s PDM link with a maximum tracking speed of 600 rad/s and BER below 2.4 × 10^-2.
• Maintained BERs around 1.7 × 10^-3 at a 100 rad/s SR for 30 minutes.
• Demonstrated the TFLN platform's capabilities for high-speed modulation and fast polarization control.

Conclusions:

• The integrated TFLN-based PDM link effectively doubles capacity per wavelength using direct detection.
• The system shows robust performance in the presence of polarization fluctuations.
• This technology holds significant potential for short-reach optical communication in data centers.