Thermal effects in 2.x µm vertical-external-cavity-surface-emitting lasers

The thermal behavior of vertical-external-cavity-surface-emitting lasers (VECSELs) is investigated. The temperature distribution in operating VECSELs has been experimentally determined for various operating conditions and different cooling schemes. The implementation of the thermoreflectance technique for the thermal analysis of VECSELs is demonstrated. This technique allows for high resolution mapping of a temperature increase resulting from the optical pumping of the VECSEL. The influence of a heatspreader on the VECSEL temperature is investigated. It is demonstrated that the use of an intracavity heatspreader bonded to the VECSEL chip causes a pronounced decrease of the temperature of the device. From the heat balance in the device, the lowering of the temperature of the VECSEL during operation is predicted. This is experimentally confirmed