High-power operation of a single-mode, linearly polarized, broadband superfluorescent fiber source has been achieved by using a two-stage cladding-pumped fiber configuration comprising a low power, single-ended, ytterbium-doped superfluorescent fiber seed source and a high-power cladding-pumped, polarization-maintaining, large-mode-area, ytterbium-doped amplifier pumped by a high-power diode source at . The source yielded a maximum linearly polarized output of with a slope efficiency of up to 67% with respect to the launched pump power and with a measured polarization extinction ratio of . The wavelength spectrum of the superfluorescent source spanned the range continuously from to , and the bandwidth (FWHM) of the emission spectrum was . The minimum seed power required for an output power over was only , corresponding to an effective power gain in the amplifier stage of . Single-spatial-mode operation with a beam propagation factor was achieved by bending the amplifier fiber to a bend radius of , without a significant reduction in output power.
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