Novel devices for hybrid and monolithic optoelectronic integration

This thesis is concerned with the development of optical and optoelectronic components which facilitate hybrid and monolithic device integration. The work described addresses two principal issues: compactness, and multi-functionality.;Compactness is a critical requirement for integrated photonic or optoelectronic circuits since many such circuits are implemented in expensive multi-layer semiconductor heterostructures. One factor inhibiting compact photonic circuit realization is the requirement to use large radius waveguide bends to avoid power losses due to radiation. Deeply etched rib waveguides can be sharply bent without suffering such losses; in the first part of this work, the implementation of multi-mode couplers in such waveguides is studied. Couplers are designed for use in a Mach-Zehnder switch, fabricated in an indium phosphide multi-quantum well semiconductor structure. High device performance is achieved using multi-mode couplers which are among the smallest ever reported. A novel mechanism for optimizing multi-mode couplers configured as optical (de)multiplexers, using circular waveguide bends, is also discussed. Devices based on this principle are designed and implemented in a silicon oxynitride glass waveguide system which is compatible with rare-earth doped materials for optical amplifier or laser implementation. (De)multiplexing performance superior to that achieved by other methods is demonstrated with a very compact device.;The second major concern addressed in this work is multi-functionality of optoelectronic components in integrated circuits. Normally, a semiconductor structure cannot operate as both a light source and a modulator at one wavelength. In this work, a multi-quantum well heterostructure ("LAMDA"--for LAser/Modulator/Detector/Amplifier) which overcomes this problem is designed and fabricated. Two quantum well stacks, with different well widths, are used to create active regions with different characteristic energies. Since guided optical fields overlap with both active regions, which can be separately biased, light generation and absorption can be simultaneously achieved at one wavelength. Computer models which were used to predict the optical and electrical characteristics of the device are described, and experimental results demonstrating operation of the device as a single cavity laser/electroabsorption modulator are presented.;Finally, a theoretical consideration of spontaneous emission in the vicinity of a planar dielectric waveguide is discussed. This work is an extension of some of the quantum mechanical theory used in the design of LAMDA, and is used to examine the spontaneous emission characteristics of optically pumped rare-earth doped planar waveguide amplifiers.