Amplification in Yb:YAG glass-clad single-crystal fiber to 16 W average power

Yb-doped YAG (Yb:YAG) single crystal fiber is an attractive material system for high power fiber lasers. Their intrinsic properties allow for high power handling and narrow band amplification. However, power scaling in Yb:YAG crystal-cladded fibers has been limited to 0.5 W average power [ Opt. Express 26 , 5092 ( 2018 ) 10.1364/OE.26.005092 ]. We demonstrate power scaling in a master-oscillator power amplifier configuration of a 1030 nm, narrow line source in a 130 µm 3% Yb:YAG single crystal core fiber with a 275 µm glass cladding. An average power of 16.2 W is demonstrated, limited by heating at the input and output faces.