Compensation of front-end IQ-mismatch in coherent optical receiver

Impacts of in-phase/quadrature-mismatch (IQ-mismatch) in polarization division multiplexed-16 level quadrature amplitude modulation (PDM-16QAM) coherent optical receiver are investigated and the IQ-mismatch compensation by digital signal processing is examined. All the results are compared with those of PDM-quadrature phase shift keying (QPSK) receiver.