Silicon-on-sapphire pillar waveguides for Mid-IR supercontinuum generation.

We propose pillar integrated silicon waveguides to exploit the entire transparent window of silicon. These geometries posses a broad and flat dispersion (from 2 to 6 μm) with four zero dispersion wavelengths. We calculate supercontinuum generation spanning over two octaves (2 to >8 μm) with long wavelengths interacting weakly with the lossy substrate. These structures have higher mode confinement in the silicon - away from the substrate, which makes them substrate independent and are promising for exploring new nonlinear phenomena and highly sensitive molecular sensing over the entire silicon's transparency range.