High Power Supercontinuum Generation in Fluoride Fibers Pumped by 2 $\mu{\rm m}$ Pulses

High power supercontinuum generation in fluoride step-index optical fibers pumped with 2- μm pulses delivered by a gain-switched thulium-doped fiber laser and amplifier system is reported. An output average power of 1.25 W in the ~ 1.8-4.15 μm spectral band and 1.82 W in the ~ 1.8-3.65 μm band was achieved for two fluorozirconate fibers of different parameters. The first demonstration of Watt-level supercontinuum generation in a fluoroindate fiber is also demonstrated. The achieved output SC powers are the highest ones ever reported for fluoride fibers pumped with 2- μm gain-switched optical pulses.