High-power supercontinuum generation in a ZBLAN fiber with very efficient power distribution toward the mid-infrared

We report high-power supercontinuum (SC) generation in a step-index fluorozirconate (ZBLAN) fiber with a zero-dispersion wavelength shifted to similar to 1.9 mu m. Pumping the fluoride fiber with 2.75 W of power provided by a thulium-doped fiber amplifier, a continuous spectrum extending from similar to 0.85 to 4.2 mu m with 2.24 W of average output power was achieved. Over 61% (1.37 W) of the total output power corresponds to wavelengths longer than 3 mu m, which shows, to the best of our knowledge, the highest power conversion efficiency toward the mid-IR spectral band in relation to the output spectrum width. A linear SC power scalability up to 5.24 W, with a spectral band of similar to 0.9-4 mu m, with repetition rate and pump power provided by a 1.55 mu m fiber master-oscillator power amplifier system, is also demonstrated. (C) 2014 Optical Society of America