Data-Aided OSNR Estimation for QPSK and 16-QAM Coherent Optical System

摘要

We propose an optical signal-to-noise ratio (OSNR) estimation technique using self-equalized complementary Golay sequences for both QPSK and 16-QAM coherent optical systems. The training sequences have complementary spectra, which enable accurate channel estimation and equalization, and have length-independent constellation for high-performance estimation. Estimation performances are verified through 100- and 40-Gb/s QPSK and 200- and 80-Gb/s 16-QAM coherent polarization-multiplexed optical systems, with an accuracy of 0.4 and 0.7 dB, in both simulations and experiments, respectively.