Development of High-brightness Diode Laser Pump Modules for LIDAR Applications

Abstract-Laser diode pump modules are being developed to enable efficient longitudinal pulsed pumping of solid-state lasers. Optimization of such devices entails near micron positional alignment between elements of a diffraction limited GaP lens array and an identically pitched array of 200 single mode laser emitters. Production issues such as diode array "smile " (vertical bowing) and thermal expansion mismatch between the diode array and its heat sink have induced systematic errors compromising the final product. Through precise emitter-to-emitter spacing measurement techniques, this problem has been characterized and a solution using either silicon carbide or copper tungsten as the submount has been developed and tested. Initial tests indicate acceptable performance for developing fully stacked devices. Additional spacing optimization and emitter improvements should lead to the program achieving its goal of developing a 15 % electrically efficient 600 W peak power fully collimated stack within a 1 cm by 1 cm package at TRL 4