Watt-level 2.8 μm ultrashort pulse generation from an all-fiber Er:ZBLAN fiber amplifier

Abstract

Compact and high-power 2.8 μm ultrashort pulse laser generated in a strictly all-fiberized system is a growing interest in the field of the mid-infrared high-power laser community. In this Letter, we demonstrated the generation of watt-level 2.8 μm ultrashort pulse laser from an all-fiber Er:ZBLAN amplifier by using the red-shifted Raman soliton pulse as the seed source. As the incident pump power increased to 8.8 W, the average output power and pulse energy of the 2.8 μm soliton pulses were boosted to 1.25 W and 26.02 nJ, respectively. To achieve the all-fiber configuration, the pump laser at 976 nm was coupled into Er:ZBLAN fiber by a home-made fluoride-fiber-based side-pump combiner (FFSPC). Numerical simulations were performed by solving the generalized nonlinear Schrödinger equation, which showed that the pulse duration of amplified pulses was limited by intracavity dispersion accumulation in Er:ZBLAN fiber amplifier, and the final pulse duration was estimated to be 5 ps. To the best of our knowledge, this is the first all-fiber structured 2.8 μm ultrashort pulse amplifier with an FFSPC. Our results may provide an effective approach for the generation of all-fiber high-power mid-infrared ultrafast lasers.