Abstract
Homodyne detection is of significant interest in optical communications because it detects both the amplitude and phase information of the incoming data channel. One of the challenges in implementing a homodyne receiver is to recover the phase and frequency of the incoming data and to lock these to the local oscillator. We proposed and demonstrated a tunable homodyne detection scheme using two continuous wave pumps 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 similar to 200-km transmission over singlemode fiber (SMF-28) and dispersion compensation fiber without any carrier recovery. The BER performance of the proposed homodyne detection scheme is also performed with and without transmission.