We report the observation of ultrafast dynamics in interferometric switching using an InGaAs quantum-well laser amplifier. The switching windows, measured in a three-beam pump-probe interferometric set-up using sub-picojoule pulses of 800 fs duration at 1.57 mu m wavelength, reveal an ultrafast (similar to 2 ps) feature. This reshaping of the switching window edge was found to change substantially with the pump pulse energy, and is attributed to refractive index changes caused by the heating of the carrier distribution in the amplifier. A rate-equation model is used to analyse these results, showing very good agreement with the experimental evidence.
- PHASE MODULATION