Mid-infrared supercontinuum generation in fluoroindate fiber

Abstract

We report the generation of mid-infrared supercontinua in a step-index fluoroindate-based fiber. The large core of the fluoroindate fiber allows the guiding of multiwatt laser power over a broad spectral range. These fibers exhibit zero dispersion at 1.83 μm, minimal loss of 0.1 dB/m at 3.2 μm up to only 0.8 dB/m at 5 μm. These specifications enable mid-infrared supercontinuum generation and propagation with low loss. By using mid-infrared ultrashort laser pulses from an optical parametric amplifier, we demonstrate generation of a 20 dB spectral flatness supercontinua from 2.7 to 4.7 μm in the fluoroindate fiber, which is twice the spectral broadening compared to a ZBLAN fiber under similar conditions.

Infrared fibers

“…The potential for extended IR transmission stimulated research on the development of fluoroindate fibers in the past decade [64,223,224].…”

Supercontinuum generation from 2 to 20 μm in GaAs pumped by picosecond CO_2 laser pulses

“…The generation of SC spectra with greater than one octave of bandwidth has been demonstrated using femtosecond [2][3][4][5][6], picosecond [7], and nanosecond [8] laser pulses interacting with fibers that exhibit negative group velocity dispersion (GVD) at the pump wavelength. Here several nonlinear optical effects, such as self-phase modulation (SPM), stimulated Raman scattering (SRS), four-wave mixing (FWM), modulational instability (MI) for picosecond pulses, and soliton fission (SF) for femtosecond pulses play an important role in the generation of broadband light [9].…”

“…All of the above experiments in fibers use near-IR pump lasers (0.8-2 μm), thus limiting the generated frequencies in the mid-IR part of the spectrum. At present the broadest mid-IR SC sources covering the range from 0.8 to 5 μm are realized using IR fibers [4][5][6]8].…”

Mid-infrared, super-flat, supercontinuum generation covering the 2–5 μm spectral band using a fluoroindate fibre pumped with picosecond pulses

“…A signal drop at ~4.2 μm corresponds to absorption by CO 2 molecules in the detection system. The 5-dB flatness of the spectral intensity, achieved with 8.3 μJ pump pulses, was maintained in the wavelength interval from 2 to 5 μm (a span of 3000 nm), which represents a significant advance compared with other reports on SC generation in fluoroindate fibres232425262728.…”

“…The first report on SC generation in an InF 3 fibre was in 2013. Theberge et al 23. used a 9.5-m long 16 μm core fibre (NA = 0.14) with a cut-off wavelength at 2.8 μm pumping it by 70 fs pulses at 3.4 μm.…”