Quantum Dash Passively Mode-Locked Lasers for Coherent Wavelength Conversion System

We demonstrate an all-optical wavelength conversion system based on four-wave mixing in semiconductor optical amplifiers for quadrature phase shift keying (QPSK) and 16-quadrature amplitude modulation (16-QAM) signals using tunable dual-correlated pumps provided by the combination of a quantum dash passively mode-locked laser (QD-PMLL) and a programmable tunable optical filter. We investigate the effects of additional phase noise transfer to the wavelength converted idler due to non-ideal correlation between the comb lines of the QD-PMLL. Our studies of the wavelength conversion of QPSK and 16-QAM signals at 12.5 Gbaud using the proposed scheme find that the bit error rate performance was below the 7% forward error correction (FEC) limit over a range of pump spacing exceeding 300 GHz for QPSK signals, and conversion of 16-QAM signals was limited by the wavelength conversion scheme though was nonetheless below the 20% FEC limit.