Laser Diodes for Eye-Safe LADAR

High-power solid state lasers operating beyond 1300-nm have been proposed as “eye-safer” sources in military applications such as LADAR and directed energy weapons. Erbium-doped solid state lasers provide an attractive gain medium due to emission at eyesafe wavelengths , and the potential for low and ultra-low quantum defect pumping by diode lasers operating around 1470-nm and 1532-nm, respectively . As a result, there is currently great interest in the further development of high-power, high-efficiency diode lasers at these wavelengths to better enable efficient (direct) pumping of such laser systems. Under the proposed Phase 1 program, nLight will design, grow, fabricate, test, and deliver to the Navy (or a recipient of their choosing) a 50W (rated, 25 ºC) compact, conductively-cooled diode laser pump module, coupled to a 200 µm core, 0.22 NA fiber. The unit will emit at 1532 nm with a linewidth of 0.3 nm FWHM with an electrical-to-optical efficiency (measured at the fiber output) of 35%. As an option to the program, nLight will conduct a second iteration of design, growth, and fabrication to target improved temperature performance.