Thermal model requirements for prediction of facet temperature in electro-optical-thermal simulation of ridge lasers

The nature of heat spreading in ridge laser structures is explored using a new self-consistent electro-optical-thermal simulator with full 3D thermal modeling. The simulator consists of the solutions of the 3D heat equation and the 1D longitudinal carrier and photon rate equations. The simulator is used to investigate facet heating in a ridge laser structure and the results are compared with the predictions of models using lower dimensional thermal equations. The 1D thermal modeling approach used in previously published simulators for these structures are shown to introduce significant errors in heat flow modeling, with a resulting drastic over prediction of facet temperature. The results show that the complexity of heat flow can not properly be described by simple 1D approximations as these lack physical character and are found to compromise accuracy. A 2D approach for modeling facet heating is shown to be a significant improvement over the 1D model. However, its implementation requires a priori non-physical adjustment of material parameters to account for the otherwise three-dimensional heat flow.