Gigahertz guided-wave acoustooptic Bragg diffraction in zinc-oxide/gallium-arsenide/aluminum-gallium-arsenide composite waveguides and integrated optic RF spectrum analyzers.

摘要

In this dissertation, a rigorous theoretical analysis of the optical guided-wave (OGW), surface acoustic wave (SAW), and AO Bragg interaction between the OGW and SAW in the ZnO/GaAs/AlGaAs composite waveguide is presented.; High performance guided-wave AO Bragg cells operating at acoustic center frequencies of 800 MHz, 950 MHz, and most recently 1.1 GHz have been realized for the first time in ZnO/GaAs/AlGaAs composite waveguides. The emphasis of this dissertation is placed on the 1.1 GHz AO Bragg cells. The design and fabrication processes of the Bragg cells including the growth of GaAs/AlGaAs optical waveguides by liquid phase epitaxy and deposition of ZnO layers by rf sputtering technique are presented. The characterization of the AO Bragg cells consists of two parts. The first part concerns the characterization of the SAW, and includes the measurement of the SAW phase velocity, insertion loss, transducer conversion efficiency, {dollar}-{dollar}3 dB bandwidth, and propagation loss. The second part concerns the AO Bragg diffraction and includes the measurement of the AO {dollar}-{dollar}3 dB bandwidth, Bragg diffraction efficiency as a function of the rf power level, and incident light polarization.; In addition, the design, fabrication, and measurement of integrated optic rf spectrum analyzers (IOSA) in ZnO/GaAs/AlGaAs composite waveguide are presented. The IOSA represents the first module that incorporates AO Bragg cell and a waveguide lens pair on a common GaAs substrate. The module consists of an input coupling waveguide lens, an AO Bragg cell, and a waveguide Fourier transform lens all integrated on a sample size of 23 mm x 7 mm. Both narrow and wide band IOSAs were realized using the double-electrode tilted-chirp transducers. Therefore, this wide band IOSA module provided 36 resolvable light spots or frequency channels. The results of this first IOSA on GaAs are respectable even when compared with the best IOSA fabricated on LiNbO{dollar}sb3{dollar}. (Abstract shortened with permission of author.)