High-Efficiency, High-Temperature Laser Diodes for Naval High-Energy Laser Applications

Improving efficiency as well as increasing operating temperature of laser diode pumps for high-power fiber lasers has a far-reaching implication in terms of significantly improving the overall stringent size, weight and power (SWAP) requirements, thus enabling DEW-class fiber lasers on airborne platforms. As a result, there is currently great interest in the further development of high-power, high-efficiency, fiber-coupled diode laser pumps around 975 nm that operate at higher ambient temperatures. nLight has demonstrated world-class high-power and high-efficiency laser diodes at 975 nm. Using these successful techniques and innovative diode design concepts, nLight will optimize 975-nm laser diodes to produce maximum efficiency at 70 C and higher operating temperatures. nLight will develop higher thermal conductivity submounts in order to reduce junction temperature of the diodes, therefore achieving maximum efficiency at high operating temperatures. In addition, nLight will significantly reduce optical-to-optical losses of the fiber coupling architecture, thus maintaining the electrical-to-optical power conversion efficiency of the diode laser pumps. Under the proposed Phase 1 program, nLight will design, fabricate, and deliver to the Navy (or recipient of its choosing) a 25-W, 975-nm fiber-coupled (200 m / 0.22 NA) laser module with a power conversion efficiency of>65% at 25 C.