Considerations on geometry design of surface-emitting laser diodes

Vertical cavity semiconductor lasers have high threshold current densities due to high mirror losses induced by the short cavity. Therefore, a thorough optimisation on material quality and device design will be required to bring these devices to the same level of reliability as is the case for conventional laser diodes. In this paper, a number of aspects concerning the geometry of different types of surface-emitting lasers are discussed by considering threshold and above-threshold behaviour, amplification of spontaneous emission, and heating. The analysis is applied to GaAs-AlGaAs devices.