Nonlinear characterization of robust multimaterial chalcogenide nanotapers for infrared supercontinuum generation

Wepresent the results of an investigation of the nonlinear characteristics of a new class of robust,multimaterial, allsolid chalcogenide nanotapers prepared from high-index-contrast chalcogenide fibers. The fiber is drawn from a preform produced bymultimaterial coextrusion and consists of chalcogenide core and cladding (which dictate the optical properties) and a built-in thermally compatible polymer jacket that provides mechanical stability to the fibers and nanotapers. We measure the nonlinear refractive indices both in the bulk chalcogenide glasses using the Z-scan method and directly in the nanotapers from spectral broadening resulting from self-phase modulation using both picosecond and femtosecond pulses. Such robust nanotapers offer many opportunities for dispersion engineering to optimize nonlinear optical fiber applications such as infrared supercontinuum generation. Lowpower femtosecond pulses (∼100 W peak power, corresponding to ∼40 pJ energy per pulse) centered at 1.55 μm wavelength launched into thenanotapers generateda supercontinuumextendingover a full spectral octave, 1–2 μm. A computational model that takes into account the relevant linear and nonlinear optical parameters provides simulations that are in good agreement with the supercontinuummeasurements. © 2014 Optical Society of America OCIS codes: (190.4370) Nonlinear optics, fibers; (320.6629) Supercontinuum generation. http://dx.doi.org/10.1364/JOSAB.31.000450