High-power, fiber-coupled stack arrays for pump applications

Here we present details of the design and performance of a family of compact, fiber-coupled, multi-bar, laser-diode stacks. The highest-power variant employs a pair of 6-bar stacks and a removable 400-μm, 0.22 NA fiber to deliver >400 W at 50 A. The overall power conversion efficiency (PCE) near 976-nm exceeds 40% at 400 W in CW operation with an uncoated delivery fiber. The brightest variant reaches a power density near 800-kW/cm 2 at 976-nm through a 200-μm, 0.22 NA fiber. Module variants have been built and characterized at multiple wavelengths between 780-nm and 980-nm. Applications for such modules include pumping of active fibers, pumping of rubidium vapor and direct material processing.