ULTRAFAST CROSS-WELL CARRIER TRANSPORT IN A STRAINED MULTIPLE-QUANTUM-WELL INGAAS-GAAS P-I-N MODULATOR

We report ultrafast optical pump-probe measurements of cross-well carr ier transport in a strained multiple-quantum-well InGaAs-GaAs p-i-n mo dulator. The transmission response of the modulator is recorded over a range of reverse bias values, wavelengths, and power levels, producin g several qualitatively different response types, A simplified physica l model is developed to describe this behavior, This model includes tr ansmission changes due to exciton saturation and excitonic field scree ning, carrier emission from the quantum wells and drift through the in trinsic region, and voltage diffusion across the p- and n-doped electr odes. This model agrees well with the experimental data.