Low-complexity reset-free polarization tracking at 300 krad/s for 480 Gb/s self-homodyne coherent systems using TFLN polarization controller.

Short-reach self-homodyne coherent (SHC) systems suffer from a local oscillator (LO) power fading problem, requiring fast and robust polarization tracking under strict hardware, power consumption, and footprint constraints. However, achieving both high tracking speed and low computational complexity remains challenging for existing solutions. We propose a low-complexity reset-free polarization-tracking scheme based on a thin-film lithium niobate (TFLN) optical polarization controller (OPC). The proposed scheme enables continuous tracking without reset while significantly reducing computational complexity, thereby lowering hardware resources and power consumption. Considering the hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10-3, experiments in a 480-Gb/s DP-16QAM SHC system demonstrate a maximum state-of-polarization (SOP) tracking speed of 300 krad/s. The proposed scheme significantly reduces computational complexity while maintaining competitive polarization tracking performance, making it suitable for resource-constrained short-reach interconnects.