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

Based on the promising results obtained under Navy Phase I SBIR funding, nLight proposes a Phase II continuation toward the development of fiber-coupled high power and high efficiency diode laser pumps around 975 nm that operate at high ambient temperatures. Under the Phase I SBIR base program, nLight designed, demonstrated, and delivered to Navy a 30-W, 975-nm fiber-coupled (200µm / 0.15 NA) laser module with fiber-coupled power conversion efficiency of>63% at 25°C. This is achieved through diode laser epitaxy design optimization, improvement in heatsink thermal resistance for lower diode junction temperature, and improvement in the optical-to-optical fiber-coupling efficiency of the diode laser pump. In the proposed Phase II effort, nLight will address the key area of required improvement high temperature operation while maintaining high efficiency and scaling up power. At the end of the Phase II base program, nLight will deliver to Navy (or a recipient of its choosing) a 25-W, 975-nm fiber-coupled (200µm/0.22 NA) laser module with a power conversion efficiency of>57% at 70°C. At the end of the Phase II option program, nLight will deliver to Navy a>100W, 975-nm fiber-coupled (200µm/0.22 NA) laser module with>70% conversion efficiency at 70°C.