Mode selective semiconductor mirror for vertical cavity surface emitting lasers

摘要

A vertical cavity surface emitting laser with a mode-selective mirror. A filter is formed on the top DBR stack of a VCSEL. The filter includes semiconductor layers that are etch stops for immediately superior layers. The filter is selectively etched to create a first region that is phase matched to the top DBR stack and a second region that is phase mismatched to the top DBR stack. The second region inhibits undesired modes and provides additional absorption for the undesired modes. The first region is formed using a wet-etch process whose etch depth is controlled because the semiconductor layers are etch stops for immediately superior layers.