Multichannel wavelength multicasting for two QPSK signals based on four-wave mixing in semiconductor optical amplifier

In this Letter, for the first time, we experimentally demonstrate multichannel wavelength multicasting (MWM) for two nonreturn-to-zero quadrature phase-shift keying (NRZ-QPSK) channels based on four-wave mixing in semiconductor optical amplifier (SOA). Through the interaction with the two pumps in SOA, the input two 25 Gbps NRZ-QPSK channels are successfully simultaneously multicast to five and two new wavelengths, respectively. All the multicast channels are with a power penalty less than 2.5 dB at a BER of 10−3. A characterization of the system performance using conversion efficiency (CE) and bit error rate (BER) as figures of merit in terms of pump and signal power is also presented, the results indicate that the pump and signal power should be optimized to eliminate the introduced deleterious nonlinear components. The wavelengths of the two NRZ-QPSK channels and the two pumps need to be specified to avoid the crosstalk induced by high-order FWM.