Mid-infrared supercontinuum generation using dispersion-engineered Ge_115As_24Se_645 chalcogenide channel waveguide

Abstract

We numerically investigate mid-infrared supercontinuum (SC) generation in dispersion-engineered, air-clad, Ge(11.5)As(24)Se(64.5) chalcogenide-glass channel waveguides employing two different materials, Ge(11.5)As(24)Se(64.5) or MgF(2) glass for their lower cladding. We study the effect of waveguide parameters on the bandwidth of the SC at the output of 1-cm-long waveguide. Our results show that output can vary over a wide range depending on its design and the pump wavelength employed. At the pump wavelength of 2 μm the SC never extended beyond 4.5 μm for any of our designs. However, supercontinuum could be extended to beyond 5 μm for a pump wavelength of 3.1 μm. A broadband SC spanning from 2 μm to 6 μm and extending over 1.5 octave could be generated with a moderate peak power of 500 W at a pump wavelength of 3.1 μm using an air-clad, all-chalcogenide, channel waveguide. We show that SC can be extended even further when MgF(2) glass is used for the lower cladding of chalcogenide waveguide. Our numerical simulations produced SC spectra covering the wavelength range 1.8-7.7 μm (> two octaves) by using this geometry. Both ranges exceed the broadest SC bandwidths reported so far. Moreover, we realize it using 3.1 μm pump source and relatively low peak power pulses. By employing the same pump source, we show that SC spectra can cover a wavelength range of 1.8-11 μm (> 2.5 octaves) in a channel waveguide employing MgF(2) glass for its lower cladding with a moderate peak power of 3000 W.