This paper reports on the latest advancements in vertical high-power diode laser stacks using micro-channel coolers, which deliver the most compact footprint, power scalability and highest power/bar of any diode laser package. We present electro-optical (E-O) data on water-cooled stacks with wavelengths ranging from 7xx nm to 9xx nm and power levels of up to 5.8kW, delivered @ 200W/bar, CW mode, and a power-conversion efficiency of >60%, with both-axis collimation on a bar-to-bar pitch of 1.78mm. Also, presented is E-O data on a compact, conductively cooled, = hardsoldered, stack package based on conventional CuW and AlN materials, with bar-to-bar pitch of 1.8mm, delivering average power/bar >15W operating up to 25% duty cycle, 10ms pulses @ 45C. The water-cooled stacks can be used as pump-sources for diode-pumped alkali lasers (DPALs) or for more traditional diode-pumped solid-state lasers (DPSSL) which are power/brightness scaled for directed energy weapons applications and the conductively-cooled stacks as illuminators.

Advances in both diode laser design and packaging technology, particularly thermal management, are needed to enhance the brightness of fiber coupled diode lasers while maintaining the small size and light weight required for defense applications. The principles of design for high efficiency fiber coupling are briefly covered. Examples are provided of fielded and demonstrated 100 and 200 micron diameter fiber coupled packages ranging in output from a few hundred to kW-class units in fibers, to include sub-kg/kW capabilities.

This paper reports on the latest advancements in high-power diode laser stacks, which deliver the most compact footprint, power scalability and highest power/bar of any diode laser package. Electro-optical (EO) data on water-cooled (micro-channel) stacks with wavelengths ranging from 7xx nm to 9xx nm and power levels of up to 5.8kW, delivered @ 200W/bar, CW mode, and power-conversion efficiency of 60%, with both-axis collimation will be presented. Also, presented is E-O data on a compact, conductively cooled, hard-soldered, stack package based on conventional CuW and AlN materials, delivering average power/bar 15W operating up to 25% duty cycle, 10ms pulses @ 45C. Results from a 300W, 200mm core/0.22NA fiber coupled package that meets the critical kg/kW metric for directed energy systems will be detailed. These devices can be used as pump-sources for diode-pumped alkali lasers (DPALs), for more traditional DPSS lasers which are power/brightness scaled for directed energy weapons applications, as conductively-cooled arrays for illuminators and as diode pump sources for high brightness fiber lasers.