Highly reproducible high-index-contrast distributed Bragg reflectors with an oxidized digital-alloy AlGaAs

Abstract

We demonstrate uniform and reproducible high-index-contrast distributed Braga reflectors (HIC-DBRs) by introdudno an oxidized digital-alloy (DA) layer for low index materials. Fine-tunable DA-Al0.98Ga0.02As layers, which consists of multiple stacks of 1 monolayer (ML)-thick GaAs and 49 ML-thick AlAs layers, are used for generating stable AlxOy layers instead of a conventional, bulk AlAs layers. Highly uniform arrays of oxidized alumina are obtained through a wet-oxidation of DAAlGaAs layers, which enable practical use of HIC-DBRs for vertical cavity surface emitting lasers (VCSELs) and other resonant-cavity based optoelectronic devices. Detailed experiments together with optical calculations are also shown.