Broadband supercontinuum generation in all-normal dispersion chalcogenide microwires

Abstract

We report the first chalcogenide microwire designed with all-normal dispersion to generate supercontinuum by optical wave breaking, a low-noise nonlinear process. The chalcogenide (As2S3) microwire is coated with PMMA and tapered to a diameter of 0.58 μm to achieve the all-normal dispersion regime. The generated supercontinuum spectrum spans over an octave from 960 to >2500 nm using a microwire length of only 3 mm and a low pulse energy of 150 pJ.

Mid-infrared supercontinuum generation in silicon-germanium all-normal dispersion waveguides

“…By contrast, achieving fully coherent octave-spanning SC with high spectral flatness is possible when pumping waveguides with sub-picosecond pulses in a low all-normal dispersion (ANDi) regime. Such SCs were reported in various fiber platforms, including silica [8][9][10], silicate soft glass [11,12], chalcogenide [13][14][15][16] fibers. However, SC generation in the ANDi regime on a chip has been only achieved in a chalcogenide waveguide [17] without any discussion about the phase coherence properties across the SC spectrum.…”

A Review of Mid-Infrared Supercontinuum Generation in Chalcogenide Glass Fibers

“…These are both much greater than that of standard SMF 28 fiber (γ = 1 W −1 km −1 with 90 µm 2 ) [67]. γ can be dramatically improved by further decreasing the fiber's core diameter [68][69][70].…”

“…Unlike bare-glass-fiber tapering [154], the polymer jacket facilitates fiber drawing and helps avoid oxidation to reduce the aging of ChG fibers. Apart from improving a tapered fiber's mechanical strength, the polymer jacket can also provide dispersion engineering, as reported in the literature [69].…”

“…To overcome this obstacle, polymer jackets with large diameters have been used to coat ChG fibers for convenient handling. The commonly used polymers are PMMA [69,95], PES [61,151], and PEI [151], which are thermally compatible with ChG fibers and can be tapered without removal. Unlike bare-glass-fiber tapering [154], the polymer jacket facilitates fiber drawing and helps avoid oxidation to reduce the aging of ChG fibers.…”

“…A 3-mm-long As 2 S 3 microwire, coated with PMMA, was tapered to a diameter of 0.58 µm, and exhibited normal dispersion at all wavelengths. When pumped with a 1550 nm laser with a pulse duration of 590 fs, the generated SC covered more than an octave of bandwidth, from 960 nm to >2500 nm, but the coherence property was not discussed in the literature [69]. Liu et al [171] numerically investigated the coherence properties of MIR SC generation in tapered AsSe 2 -As 2 S 5 ChG fibers pumped at a wavelength of 4 µm with a pulse duration of 500 fs.…”