Hardware-efficient frequency offset and phase noise mitigation in coherent optical quadrature amplitude modulation systems

A hardware-efficient adaptive algorithm for frequency offset and phase noise mitigation in coherent optical quadrature amplitude modulation systems is presented and analysed. Hardware efficiency for the mitigation of imperfections is achieved by computing directly the complex exponential, thus avoiding a CORDIC processor in the phase recovery loop. The design includes a square-root- and trigonometry-free update. Simulation results substantiate the theoretical findings.