Wavelength-Beam-Combined Diode Laser Pumps for High-Power Fiber Lasers

There is a compelling need for scaling fiber lasers and amplifiers to higher power and energy for industrial and military applications. The primary scaling roadblock today is the very limited brightness of diode laser pumps. We propose to produce the highest brightness diode laser pump sources for fiber lasers demonstrated to date. The Phase II deliverable laser will be a compact 5 kW diode laser coupled to a 200-µm, 0.11 NA output fiber (wavelength stabilized to 976 nm with a spectral linewidth less than 3 nm) for pumping ytterbium-doped silica fiber lasers and amplifiers. This brightness level is more than an order of magnitude higher than that of state-of-the-art commercial fiber-coupled diode lasers. The laser module prototype will be assessed for reliability, and will be suitable for testing in a high-fidelity laboratory environment or in a simulated operational environment, consistent with Technology Readiness Level 6 guidelines.