Thin Film Optical Waveguides in III-V Semiconductors.

摘要

The objectives of this program are (1) to grow a variety of epitaxial GaAs, GaAsP, and GaAlAs waveguide structures, (2) to evaluate their performance for guided wave propagation, and (3) to use and to optimize them for device applications. Most of the samples were grown by the vapor phase epitaxial technique. A few samples were grown by the liquid phase epitaxial technique. The effect of layer thickness, alloy composition, surface quality and carrier concentrations on waveguide attenuation has been evaluated at 10.6 micrometers wavelength. Some attenuation data have also been collected at 1.06 micrometers. Waveguides with attenuation rate in the range of one to two db/cm have consistently been obtained at both 10.6 micrometers and 1.06 micrometers. The use of these waveguides for electrooptical modulation at 10.6 micrometers wavelength was analyzed and demonstrated. Comparison of the various waveguides and optimization of the waveguide design for electrooptical modulation has been carried out. A limited amount of effort has also been made to investigate grating couplers and fiber to film coupling.