OPTIMIZATION OF PUMP AND SIGNAL POWERS FOR WAVELENGTH CONVERTERS BASED ON FWM IN SEMICONDUCTOR OPTICAL AMPLIFIERS

We investigate the effect of input pump and signal powers on the noise performance and intersymbol interference (ISI) in a frequency-convert er based on four-wave mixing in a semiconductor optical amplifier, We demonstrate that there is an input pump power at which the noise figur e of the frequency converter is a minimum, and a corresponding input s ignal power for which the output signal-to-noise ratio (SNR) is a maxi mum, We report bit-error-rate measurements which show that there is a trade-off between maximizing the output SNR, and minimizing intersymbo l interference in the SOA. Consequently, the power penalty incurred in the frequency conversion can be minimized by careful selection of the input signal power, We show that power penalties of less than 1 dB ar e achievable.