Adaptive Stokes-Based Polarization Demultiplexing for Long-Haul Multi-Subcarrier Systems

We experimentally evaluate the performance of the adaptive Stokes polarization demultiplexing (PolDemux) algorithm over a long-haul optical link considering the propagation of 31 × 192 Gb/s channels modulated as PM-16QAM multisubcarrier (MSC) signals. Initially, we consider 1 × 24 Gbaud channel under test, and subsequently, we assess the performance of the algorithm on an increasing number of subcarriers (up to 12 × 2 Gbaud) while keeping the same aggregate symbol rate. Taking advantage of the higher robustness of MSC signals toward chromatic dispersion (CD), we demonstrate that the memoryless Stokes-based PolDemux algorithm, originally designed for short reach links, can also be used for low-complexity and modulation transparent polarization demultiplexing in long-haul systems. In addition, we demonstrate that the PolDemux rotation matrix for the MSC signals can be estimated over a restricted group of Nref subcarriers and seamlessly applied to all Nsc subcarriers, thereby significantly reducing the overall complexity by a factor of ~Nsc/Nref.