Power scalable 30-W mid-infrared fluoride fiber amplifier

A fluoride-fiber-based master oscillator power amplifier (MOPA) for 30-W class continuous-wave (cw) operation at 2.8-μm wavelength has been demonstrated. To overcome the low durability of ZBLAN fibers, various novel technologies for using fluoride glass with a ZBLAN-fiber-based side-pump combiner have been adopted in the system. A maximum cw output power of 33 W and stable operation under 23-W output have been demonstrated. We suggest that such fiber MOPA systems will open up advanced fluoride fiber technology for next-generation high-power mid-IR lasers.