Tunable homodyne detection using nonlinear optical signal processing to automatically lock a “local” pump laser to an incoming 20-to-40-Gbaud QPSK data signal

We propose and demonstrate tunable homodyne detection using nonlinear optical signal processing to automatically lock a “local” pump laser to an incoming 20-to-40-Gbaud QPSK data signal. Open eyes are obtained for both in-phase and quadrature components of the signal after ~200-km transmission over SMF-28 and DCF fibers. The BER performance of the proposed homodyne detection scheme is also compared with the conventional intradyne receiver.