Influence of the intracavity heatspreader on the VECSEL temperature

Vertical External Cavity Surface Emitting Lasers (VECSELs) are a new breed of semiconductor lasers, combining the high quality of output beam (TEM00) with multi-watt output power. The emission is obtained through optical pumping with high power laser. The main limitations of the device performance are thermal. The output power is limited by the thermal roll-over effect occurring at higher pump powers, due to overheating of the active region. To obtain reliable and efficient device operation, thermal management has to be introduced. This paper presents one of the measures applied to lower the device temperature, namely the intracavity heatspreader approach. The plate of the high thermal conductivity material is liquid capillary bonded to the semiconductor chip to extract the photo-generated heat out of the active region. The effect of the heatspreader on the device temperature is studied both experimentally by thermoreflectance and numerically by FEA.