Cavity and reflector design for vertical cavity surface emitting lasers

Abstract

The reflectivity of dielectric quarter-wave Bragg reflectors is analysed theoretically. The limiting reflectivity of lossy stacks determines minimum gain required for threshold in a vertical cavity, surface emitting laser (VCSEL). The effects of short cavities and resonant periodic gain (RPG) media are also discussed and useful mathematical expressions for device design are presented. Particular examples are made of AlAs/GaAs-based reflectors for 1.0 µm operation, although the concepts are applicable to any material system.