Reactive ion etching of deeply etched DBR-structures with reduced air-gaps for highly reflective monolithically integrated laser mirrors

Abstract

An electron cyclotron resonance reactive ion etching process is investigated for the fabrication of third order deeply etched distributed Bragg reflectors suitable for monolithically integrated laser mirrors. At a period of 550-nm, air-gaps as small as 150 nm down to a depth of 4.5 μm were realized in AlGaAs/GaAs heterostructures. The reflectivity of the deeply etched DBRs was tested by the device properties of microlasers with a cleaved facet on one side and a DBR on the other side. From the light output characteristic of the lasers a systematic improvement of the mirror reflectivity is observed by reducing the air-gap.