Polarization Controller Based on Variable-Step Greedy Linear Descent for Self-Homodyne Coherent Transmission Systems

A self-homodyne coherent (SHC) transmission system that has a good prospect in terms of short-reach interconnections can simplify digital signal processing (DSP) and reduce the power consumption laser diodes. However, polarization control carrier becomes pivotal part these systems, different from traditional on certain state (SOP), it only needs to lock two lights after beam splitter (PBS) equal power. Half-wave plates or Mach–Zehnder interferometers accomplish above goals. In order evaluate performance structures SHC system, we modeled them basis theoretical analysis. Furthermore, variable-step greedy linear descent (GLD) algorithm is proposed solve fluctuation problem caused by accelerated change SOP near pole Poincaré sphere. The simulation results indicate GLD effectively improve tracking ability loop up approximately 1.5 times gradient (GD) algorithm.