An adaptive modified decision-directed algorithm for electronic polarization control in coherent QPSK optical transmission

In this paper an adaptive modified decision-directed algorithm (MDDA) for the electronic polarization control of the polarization-multiplexed coherent optical QPSK transmission is proposed. The algorithm utilizes a variable control gain instead of a fixed control gain. Simulations with a coherent QPSK transmission system show that this algorithm converges faster and experience minimum local oscillations at the steady state. BER performance of the algorithm is comparable to that of the modified decision-directed algorithm.