Semiconductor optical fibres for nonlinear applications in the mid-infrared

Nonlinear silicon photonics in the mid-infrared (mid-IR) is attracting increased interest with applications ranging from broadband telecommunications to sensing and spectroscopy. Recent reports have shown that hydrogenated amorphous silicon (a-Si:H) can exhibit low transmission losses, a high refractive index similar to the crystalline material, an even higher Kerr nonlinearity, though is much cheaper to produce. In this paper we extend the characterization of our a-Si:H core fibres beyond the telecommunications window of ~1.5µm and present the first measurements of the transmission properties up to the edge of the mid-infrared regime. The results show that the nonlinear figure of merit (FOMNL = n2/beta[TPA]lambda ) increases dramatically over this region, with FOMNL > 20 around 2µm and above in Fig. 1(a) which open up the possibility of these fibres for nonlinear applications in the mid-IR regime.