| Two of the main challenges involved with the fabrication of integrated photonic devices are the control of the in-plane band gap and the formation of integrable high-Q cavities. In-plane bandgap control is required to fabricate emitters, passive waveguides, detectors, and modulators all on a single wafer and all optimized for operation at a particular wavelength. The formation of integrable high-Q cavities is needed to integrate the laser source.; Selective-area epitaxy (SAE) is a powerful technique which enables the tailoring of the in-plane band gap energy to fabricate numerous optimized photonic devices on a single wafer. In this dissertation, a three-step SAE process in the InGaAs-GaAs-AlGaAs material system is investigated. This process produced discrete Fabry-Perot lasers with threshold currents as low as 2.65 mA for an uncoated device and 0.97 mA for a coated device. Several integrated photonic devices that utilize the in-plane bandgap control of this SAE process are also investigated. These devices include lasers with nonabsorbing mirrors, dual-channel wavelength division multiplexing sources with integrated coupler, lasers with integrated photodiodes, lasers with integrated intracavity modulators, and lasers with integrated external cavity modulators.; The second challenge involved with the fabricating of integrated photonic devices is the formation of integrable high-Q cavities. The optical feedback in most laser diodes is provided by cleaved facets. Unfortunately, cleaved facets are not an option when designing integrated photonic devices. However, optical feedback can be provided in integrated photonic devices using distributed Bragg reflectors (DBRs). In this dissertation, ridge-waveguide DBR lasers with first-order surface gratings are investigated. These lasers exhibit low thresholds (6 mA), high slope efficiencies (0.46 W/A), and single-frequency operation with narrow linewidths ({dollar}<{dollar}25 kHz). By varying the period of the first-order DBR grating, a wide wavelength range of 540 A (15.2 THz) is obtained with threshold currents and slope efficiencies remaining below 10 mA and above 0.40 W/A, respectively, over the entire wavelength range. These gratings are also used to fabricate DBR lasers with monolithically integrated external cavity electroabsorption (EA) modulators without modification of the active region. |
