The development of compact and reliable ultrafast sources operating in the mid-infrared region could lead to major advances in both fundamental and applied sciences. In this Letter, we report on a simple and efficient laser system based entirely on erbium-doped fluoride glass fibers that generates high-energy Raman soliton pulses tunable from 2.8 to 3.6 μm at a high average output power. Stable 160 fs pulses at 3.4 μm with a maximum energy of 37 nJ, a corresponding average output power above 2 W, and an estimated peak power above 200 kW are demonstrated. This tunable source promises direct applications in laser processing of polymers and biological materials.

A mid-infrared supercontinuum source spanning from 3 to 8 μm is demonstrated using a low-loss As₂Se₃ commercial step-index fiber. A maximum average output power of 1.5 mW is obtained at a low repetition rate of 2 kHz. Thanks to the low NA step-index fiber, the output is single mode for wavelengths above ∼5  μm. The pump source consists of an erbium-doped ZrF₄-based in-amplifier supercontinuum source spanning from 3 to 4.2 μm. The effects of both the pump power and As₂Se₃ fiber length on the output characteristics are studied. To the best of our knowledge, this is the first compact supercontinuum source ever reported to reach 8 μm in a standard step-index fiber.

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We report on infrared supercontinuum (SC) generation in step-index fluoroindate-based fiber by using an all-fiber laser source. In comparison to widely used ZBLAN fibers for high-power mid-infrared (MIR) SC generation, fluoroindate fibers have multiphoton absorption edges at significantly longer wavelengths and can sustain similar intensities. Recent developments highlighted in the present study allowed the production of fluoroindate fibers with MIR background loss of 2 dB/km, which is similar to or even better than ZBLAN fibers. By using an all-fiber picosecond laser source based on an erbium amplifier followed by a thulium power amplifier, we demonstrate the generation of 1.0 W infrared SC spanning over 2.25 octaves from 1 μm to 5 μm. The generated MIR SC also exhibits high spectral flatness with a 6 dB spectral bandwidth from 1.91 μm to 4.77 μm and an average power two orders of magnitude greater than in previous demonstrations with a similar spectral distribution.

We report on infrared supercontinuum (SC) generation through subsequent nonlinear propagation in concatenated step-index fluoride and AsSe fiber. These fibers were pumped by an all-fiber laser source based on an erbium amplifier followed by a thulium power amplifier. ZBLAN and InF fibers were compared for the concatenated scheme. The broadest SC produced was achieved by optimizing the length of the InF fiber. This arrangement allowed the generation of 200 mW infrared SC with high spectral flatness and spanning from 1.4 μm to 6.4 μm.