Watt-level mid-infrared supercontinuum generation from 2.7 to 4.25 μm in an erbium-doped ZBLAN fiber with high slope efficiency

A watt-level mid-infrared supercontinuum (MIR-SC) spanning 2.7 to 4.25 μm is generated in an erbium-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber amplifier (EDZFA). A broadband fiber-based SC covering 2.2–3.1 μm region is used to seed the amplifier. The generated SC has a maximum output power of 1.75 W with an overall slope efficiency of 20.5%. A normalized root mean square (RMS) in power of 0.5% shows that our system is highly stable. This research, to the best of the authors’ knowledge, demonstrates both the record power and the record slope efficiency of in-amplifier MIR-SC generation to date.