Bright octave-span mid-IR supercontinuum generation in silicon germanium waveguide

We present silicon-germanium on silicon waveguides as a suitable platform for on-chip supercontinuum generation in the mid-infrared. We report low propagation loss (<0.4dB∕cm) in the 3.5-5 μm range, leading to an octave spanning supercontinuum extending up to 8.5 μm with a high average power of more than 10 mW on-chip. Furthermore, we present the addition of a chalcogenide cladding layer as a simple post-processing technique to fine tune the waveguide dispersion which, in turn, governs the properties of the generated supercontinuum.