Detailed investigation of the pump phase noise tolerance for wavelength conversion of 16-QAM signals using FWM

All-optical wavelength conversion (WC) of advanced modulation formats could have a significant role in the next generation of high-capacity optical networks. Four-wave mixing (FWM) occurring within a semiconductor optical amplifier is one of the most advantageous methods to implement all-optical WC. We demonstrate the WC of 16-quadrature amplitude modulation (16-QAM) using degenerate and nondegenerate FWM in a semiconductor optical amplifier. We pay particular attention to the phase noise transfer from the pump(s) to the converted signal. The class of laser that can be used as the pump source to implement the scheme is highlighted by the calculations of the required pump laser linewidths to achieve specific system bit error rate performance at the forward error correction threshold. Our results are consistent with theories of phase noise transfer between the pump and converted signals.