All-Fiber Mid-Infrared Enhanced Supercontinuum Generation in an Erbium-Doped ZBLAN Fiber Amplifier

We demonstrated all-fiber mid-infrared enhanced supercontinuum generation in an Erbium-doped ZBLAN fiber amplifier. A 2 μm low repetition rate noise like-pulse mode-locked fiber laser was adopted as the pulse seed for the system. After amplified in a Thulium-doped fiber amplifier, the noise like-pulse generated a supercontinuum covering the range from ∼2 μm to ∼3.8 μm in a piece of InF
₃
fiber. Then, the supercontinuum was injected into an Erbium-doped ZBLAN fiber amplifier as the seed for the next stage in-amplifier mid-infrared enhanced supercontinuum generation. A novel silica-fluoride fiber pump combiner was designed and fabricated to couple the 976 nm LD pump laser into the Erbium-doped ZBLAN fiber. The supercontinuum laser source realized mid-infrared enhancement and power boosting beyond 2.7 μm in the Erbium-doped ZBLAN fiber amplifier. A ∼1.4 W mid-infrared enhanced SC with long wavelength edge of ∼4200 nm and 97% power beyond 2.7 μm was obtained. This simple and compact all-fiber supercontinuum laser source has a great potential application in the 3–5 μm molecular fingerprint region.