The general purpose of these studies is to obtain a better understanding of parameters governing ultra-short pulse generation, propagation, and nonlinear interaction in semiconductor thin films and active waveguides. Results of such studies are expected to facilitate the design of future high-rate optical communication and signal processing devices. Topics of particular current interests are: ultrafast gain and loss dynamics in diode lasers, limitations on pulse formation and propagation in semiconductor waveguides, femtosecond carrier dynamics in InGaAs and InGaAsP, and nonlinear coupling phenomena in active waveguides. The proposed work is primarily experimental; and an important aspect is the development of novel femtosecond diagnostic techniques. Specific goals are outlined in three sections. (a) Wavelength-tunable studies of sub-picosecond gain and absorption nonlinearities in GaAlAs and InGaAsP diode lasers. (b) Dynamic index of refraction changes in active semiconductor wave-guide devices. (c) Improved femtosecond diagnostics for the long-wavelength regime.
