The Thermal Resistance of High-Power Semiconductor Disk Lasers

We present a model for the simulation of the thermal resistance of flip-chip bonded vertical-external-cavity surface-emitting lasers based on the finite-element method. Therefore, we take on and deepen precedent models with regard to three modifications. Our model for the first time comprises the complete heat removal, incorporates temperature-dependent heat conductivity of the diamond heat spreader and features the consideration of the exact pump distribution. The simulations are accompanied by an extensive experimental investigation of four gain chips. Thereby, a high accuracy of our simulations is confirmed. In addition, we use our model in order to investigate the influence of a ternary distributed Bragg reflector, which lacks in pump light absorption and the subsequent additional heating. Recently, this model was used to push the output power of vertical-external-cavity surface-emitting lasers beyond 100 W.