110 W double-ended ytterbium-doped fiber superfluorescent source with M2=1.6

High-power operation of a broadband superfluorescent fiber source has been achieved via the process of amplified spontaneous emission (ASE) in a double-clad Yb-doped multimode-offset-core fiber by using a novel fiber-end termination geometry to suppress lasing. The fiber was cladding pumped by a high-power diode source at 976 nm and yielded a maximum ASE output of 63 and 47 W from the two ends of the fiber, respectively. The maximum combined ASE output was 110 W with slope efficiency with respect to launched pump power of up to 68%. The wavelength spectrum of the ASE source spanned the range from similar to 1032 to 1120 nm, and the bandwidth (FWHM) of the emission spectrum was 40 mn. The output beam was slightly multimode with a beam-quality factor (M-2) of 1.6. The prospects for further improvement in performance are considered. (c) 2006 Optical Society of America.