Ridge waveguide mid-infrared indium gallium arsenic antimonide quantum well lasers fabricated with pulsed anodization etching.

摘要

Mid-infrared quantum well lasers based on the InGaAsSb/AlGaAsSb material system are designed and demonstrated. Various aspects of the strained quantum well laser diode in this material system were extensively studied: the development of an etching technique, the design of a thin p-clad ridge waveguide structure, and the characterization of ridge waveguide lasers fabricated with the newly developed etching technique. Theoretical modeling also confirmed experimental results.; Deep etching of p-cap GaSb/p-clad AlGaAsSb layers was demonstrated using a single step, pulsed anodization/etching for the first time. A new electrolyte composed of glycol, water, and two acids was used. An important feature of this technique is the realtime, electrical detection of layer interfaces in the diode laser structure.; Ridge waveguide lasers fabricated with this PAE technique have demonstrated very low threshold currents at room temperature in both pulsed and continuous-wave operation with emission wavelengths of 1.8--1.9 Am. These experimental results imply that the pulsed anodization/etching with the new electrolyte system is a viable process for fabricating high quality ridge waveguide InGaAsSb quantum well diode lasers.; In order to possibly raise the continuous-wave operating temperature and output power capability, an asymmetric waveguide structure was designed in the InGaAsSb quantum well laser by decreasing the thickness of the p-clad layer. This design requires a shallow etching step in fabricating ridge waveguide lasers and could lead to a scheme for fabricating distributed feedback lasers without need of an epitaxial regrowth process. The pulsed anodization/etching technique was used to fabricate the first thin p-clad InGaAsSb quantum well lasers that operated continuous-wave at room temperature at an emission wavelength of 2.2 Am.; Theoretical modeling was conducted to compare with experimental data. The emission wavelengths were in good agreement with theoretical calculations that involve strain effects on the band lineups and several interpolation schemes for material parameters of InGaAsSb and AlGaAsSb quaternaries.