Wavelength-Stabilized, High-Brightness Diode Laser Pumps for High-Power Fiber Lasers

nLight proposes the development of a wavelength-stabilized 5 kW, 105 m, 0.22NA fiber-coupled 976 nm diode laser pump system with a final predicted power conversion efficiency of>45% and mass-to-power ratio of<1 kg/kW. The program will leverage nLight"s wavelength-stabilized 100 W, 105 m, 0.22NA fiber-coupled 976 nm diode laser module, which will serve as the principal building block of the proposed system. Brightness and power will be scaled via wavelength beam combining, effectively trading the ultra high spectral brightness made possible by VBG-locking for increased spatial brightness. Because the spectral bandwidth of each channel in the system can be reduced to<0.05 nm,>50 individual channels (each operating at 100 W) can be efficiently fit within a 3 nm total bandwidth, ensuring excellent absorption by the 976-nm transition in Yb-doped fiber. This effort will represent the confluence of multiple technologies in which nLight has deep experience, making nLight well-positioned to meet all of the specifications set forth in the solicitation. During the Phase 1 program, nLight will investigate design considerations for the wavelength beam combining technique and demonstrate feasibility of the approach by applying it to a 2-channel 200 W (rated), 105 m, 0.22NA fiber-coupled system.