Ultrashort pulse-propagation effects in a semiconductor optical amplifier: microscopic theory and experiment

We present microscopic modeling and experimental measurements of femtosecond-pulse interactions in a semiconductor optical amplifier. Two novel nonlinear propagation effects are demonstrated: pulse break-up in the gain regime and pulse compression in the transparency regime. These propagation phenomena highlight the microscopic origin and important role of adiabatic following in semiconductor optical amplifiers. Fundamental light-matter interactions are discussed in detail and possible applications are highlighted.