Blind Joint Polarization Demultiplexing and IQ Imbalance Compensation for M-QAM Coherent Optical Communications

A novel joint polarization demultiplexing and IQ imbalance compensation scheme for coherent optical communications that uses global update is proposed and analyzed through numerical simulations. We describe the system model and derive its related equations. Next, we formulate our blind $M$ -QAM arbitrary approach based on EASI algorithm and using the second-order statistics of the observed signals. A comparison of the proposed joint method with the traditional constant modulus algorithm (CMA) for polarization demultiplexing followed by blind signal estimation (BASS) for IQ imbalance compensation is also reported. Evaluated metrics (EVM, MSE, BER) demonstrate its effectiveness compared with CMA cascaded with BASS algorithm.