Research in the Development of Thin-Film Devices and in the Study of Device Physics for Optical Communications and Optical Electronics.

摘要

Our research effort is reviewed in four basic areas: (1) experimenting with new laser structures for providing two-dimensional waveguiding to control lateral modes, (2) investigating suitable waveguiding structures for use as the building block for future monolithic integration of optical components based on GaAs technology, (3) developing technologies related to material aspects for GaAs and related semiconductors, such as oxide formation and LPE growth of quaternary compounds, and (4) studying and demonstrating the use of Ti-diffused LiNb03 waveguides in integrated-optics applications as modulators and power dividers. Using LPE growth over chemically etched channels we have developed new lasers with two-dimensional waveguides to stabilize the lateral modes. These lasers show linear light versus current relation, stable radiation pattern, and single mode operation up to 2 Jth capable of delivering 70 mW power. Using a waveguide structure containing a large optical cavity (LOC), we have been able to integrate a DBR laser with a detector and with a modulator. The LOC scheme enables us to remove the GaAs layer from the passive regions, which in turn makes possible the attainment of high differential quantum efficienty in the DBR laser and also the use of the same structure as the building blocks for monolithic integration. The fabrication requires only a one-step LPE growth. As a preparation for future work, preliminary experiments on anodic oxidation of GaAs, high temperature effects in LPE layers grown on GaAs wafers, and LPE growth of (GaIn) (AsP) layers have been initiated to gain experience and insight as to the problems involved.