Time-delay characteristics of four-wave mixing among subpicosecond optical pulses in a semiconductor optical amplifier

We have studied four-wave mixing (FWM) characteristics among subpicosecond optical pulses in a semiconductor optical amplifier for different time-delays between pump and probe beams, for the first time. Our experimental results have shown that an optimum time-delay shifted from the perfect pump-probe overlap condition with an increase in input probe beam energy. An optimum intensity of the pump beam has also been obtained to generate the maximum FWM signal.