Low Complexity Carrier Recovery Based on Gradient Descent for Optical Communication

A carrier recovery algorithm based on gradient descent with parallelized architecture is proposed for BPSK/QPSK modulated optical communication, and the recovery performance has been validated experimentally. A simplified Mth-power operation implementation method is introduced, which considerably lowers the algorithm complexity. Experimental results demonstrate that, with the proposed algorithm in this letter, both quick tracking ability and stable estimation accuracy comparable to the LKF-based algorithm can be achieved, which is better than the traditional FFT&VV and Diff&VV algorithms under different SNR; moreover, for BPSK/QPSK switchable system, it can save 36.3% of CLB LUTs and 30.9% of CLB registers FPGA chip resource compared to the LKF-based algorithm, within a 64-channel FPGA-based parallel architecture.