Measurement of self- and cross-gain saturation dynamics using two-color heterodyne pump-probe technique

The gain dynamics of a symmetrical multiple-quantum-well semiconductor optical amplifier (SOA) with wide gain-bandwidth are measured by a two-color heterodyne pump-probe technique. Short optical pulses are generated by using optical filters to select spectral components from compressed supercontinuum optical pulses. To maintain durations of the order of 100 fs over the entire gain bandwidth of the SOA, the pulse broadening caused by frequency shifters is compensated by fibers with lengths optimized for respective wavelengths. We measure the wavelength dependences of the recovery time of carrier heating (CH) and the gain reduction due to CH. The gain reduction caused by spectral hole burning is observed.