Investigation into semiconductor optical amplifier (SOA) high quality four- wave mixing (FWM) wavelength conversion

In this work, we have measured the signal-to-noise (SNR) ratio and Q-factors in a degenerate four-wave mixed (FWM) converted wavelength signal from a dual semiconductor optical amplifier (SOA) arrangement at different data rates, various SOA input powers, and changing converted wavelength spans. The results show that operating the functional SOA at optimum input power and increasing the saturation input power to the SOA pre-amp substantially improves the quality of the FWM signal. The optimum data rate to operate at was found to be around 600 Gb/s for a 4 nm down shift, with quality conversion still achieved at 1 Tb/s. Link length travel of around 280 km was shown to be possible for the FWM signal under the right conditions, with excellent receiver sensitivity shown. The modelled findings reported here should give practical designers an idea of how to optimize a converted FWM signal regarding trade-offs between SOA input power, gain, link length, data rate, and required conversion bandwidth.