High efficiency oxide confined vertical cavity surface emitting lasers

Structures based on aluminum-oxide layers have led to dramatic improvements in VCSELs such as power conversion efficiencies in excess of 50% and threshold currents below 10 μA. The low index, insulating aluminum-oxide, formed by selective wet thermal oxidation of AlGaAs, serves as an effective index guide as well as a current injection aperture. A substantial amount of design freedom exists with respect to the number and placement of apertures with published structures varying from single apertures to one per mirror period. In this paper we present data on devices with either two aligned apertures above and below the active region or with a single effective aperture above the active region leading to slope efficiencies of up to 1 W/A