Advances in manufacturing of high peak energy diode laser stacks

We present a novel method for the assembly of monolithic diode laser stacks comprising up to 52 laser diode bars with a 0.5 mm pitch. These stacks utilize 940 nm and 871 nm laser bars, which are AuSn soldered onto CuW submounts. The monolithic stack is created by joining 52 bar-on-submounts (BoS) using an electrically conductive material. A robotic system is employed to position these BoS into fixtures for the bonding process. Additionally, we demonstrate the attachment of the monolithic stack to an insulated micro-channel cooler using an electrically insulating bonding material. The use of innovative bonding materials at lower joining temperatures, in contrast to traditional soldering techniques, results in a stack assembly that experiences reduced induced stress, facilitating the creation of monolithic stacks with a higher number of elements. We demonstrate peak power of up to 990W per bar at 0.4% duty cycle and 1,000A peak current with an average junction temperature of 74°C, with over 51kW total peak power.