14–72 μm broadband supercontinuum generation in an As-S chalcogenide tapered fiber pumped in the normal dispersion regime

We report a broadband supercontinuum (SC) generation in chalcogenide (ChG) step-index tapered fibers pumped in the normal dispersion regime. The fibers consisting of As2S3 core and As38S62 cladding glasses were fabricated using the isolated stacked extrusion method. A homemade tapering platform allows us to accurately control the core diameters and transition region lengths of the tapered fibers. An SC generation spanning from 1.4 to 7.2 μm was achieved by pumping a 12-cm-long tapered fiber with femtosecond laser pulses at 3.25 μm. To the best of our knowledge, this is the broadest SC generation obtained experimentally in tapered fibers when pumped in the normal dispersion regime so far. The effects of waist diameter and transition region length of the tapered fiber on the SC spectral behavior were also investigated.