400W monolithic high efficiency 2 μm MOPA

Progress is being made developing monolithic, all-fiber 2μm wavelength devices that operate robustly at higher power levels. This development includes the critical Tm-doped LMA fiber technology, compatible components such as pump combiners and couplers, along with the optimization of high brightness, high efficiency 790nm pump diodes. In this paper we present recent CW power scaling results and demonstrate a monolithic MOPA system operating at 400W output power with around 20% E-O efficiency.