10 W widely tunable narrow linewidth double-clad fiber ring laser

A highly efficient and widely tunable narrow linewidth ytterbiumdoped double-clad fiber laser with a linearly polarized output power of 10 W is demonstrated. The laser wavelength was tunable over a range of 24 THz from 1032 nm to 1124 nm by using a diffraction-grating pair in Littrow-Littman configuration in a unidirectional ring-cavity. The laser linewidth was smaller than 2.5 GHz for all power levels and all laser wavelengths. Additionally, an operating mode without any measurable amplified spontaneous emission with a linearly polarized output power of up to 3 W was realized.