Technologies of oxide confinement and high contrast grating mirrors for mid-infrared VCSELs

International audienceA new architecture for mid-infrared (MIR) Vertical Cavity Surface Emitting Laser (VCSEL) is proposed and fabricated. The MIR-VCSEL structure includes both a lateral confinement by an oxide aperture, and a high-contrast sub-wavelength grating mirror (HCG mirror) formed by the high contrast combination AlOx/GaAs, and that replaces conventional GaSb/AlAsSb top Bragg mirror. Upon the GaSb-based half-microcavity bottom part, a metamorphic AlGaAs heterostructure was epitaxially grown to enable thermal oxidation and grating mirror fabrication steps on AlGaAs material platform. The optical design of the VCSEL structure and more precisely the HCG mirror has been optimized thanks to an original methodology based on optimization and anti-optimization methods, resulting in improved parameter tolerances regarding processing errors. After all, we show the complete fabrication of an electrically-pumped MIR monolithic VCSEL structure by integrating this new technological bricks