Diffraction-limited 308 W at ∼980 nm from a monolithic ytterbium fiber laser

This is the authors' abstract. We don't add key points for this paper.

Diffraction-limited 308 W at ∼980 nm from a monolithic ytterbium fiber laser operating at the three-level laser system has been demonstrated, limited only by the available pump power, doubling the previous record and showing significant potential for further power scaling thanks to the availability of high brightness pumps and ytterbium-doped all-solid photonic bandgap fibers optimized for suppressing the four-level system. New record slope efficiencies of 72 % and 81 % for three-level lasers with regard to launched and absorbed pump powers respectively are also set.