As power densities of laser diodes continuously increase, the effects of absorption losses in fast axis collimation lenses become exceedingly important. We report our analysis of two drivers of these absorption losses, coating absorption and glass bulk absorption, and how these absorption losses cause a thermal impact and have an influence on the performance of the laser beam quality emitted from a laser diode equipped with a fast axis collimation lens on a bottom tab. The presented results are derived from finite element method (FEM) simulations and the FEM model used is based on material data from data sheets and a heat transfer coefficient derived from cooling curves of components observed by a thermal infrared camera.
Methods for thermal modeling, analysis and optimization are presented. Modeling distinguishes between three basic types of lens mounts. For analysis also FEA-results are incorporated in the optical model. Optimization with a simple, glass substitution method and a paraxial method is presented.