Highly Coherent Supercontinuum Generation in a Silicon Nanowire with Sub-Wavelength Air-Hole

In this paper, we describe possible supercontinuum generation (SCG) in a special silicon nanowire with a central air hole. The addition of an air hole enhances the nonlinearity of nanowire structures which already exhibit highly nonlinear properties. This results in an wideband and coherent SCG spectrum. We demonstrate the dependency of the optical mode characteristics and the bandwidth of the spectrum on the air hole size and are able to estimate a maximum bandwidth of 370 THz for a low pulse power of 300 W at 2 μm wavelength, which is significantly higher than that obtained without the air hole.