ARROW guiding silicon photonic crystal fibres

In this paper we describe a new class of silicon photonic crystal fibre (SiPCF) that brings together two powerful optical technologies, the photonic crystal fibre (PCF) and the semiconductor optical fibre. The PCF is now a well established fibre paradigm that has proven to be a very versatile waveguide and has found applications in nonlinear optics, fibre lasers, and sensors. The versatility of the PCF is due to its microstructured cladding which enables complex manipulation of the waveguide's characteristics, and also allows for enhanced light interaction with materials that are infiltrated into the cladding voids. The most typical form of semiconductor optical fibre has a fused silica cladding and guides light in the high refractive index semiconductor core. Although semiconductor optical fibres are a nascent technology, practical applications, such as nonlinear pulse shaping and all optical modulation, have begun to emerge in the last couple of years. However, material losses are currently preventing this fibre type from becoming a major disruptive technology and, with this in mind, we present the first steps to decouple the functionality of the semiconductor from its material losses. We achieve this by filling the holes of a modified total internal reflection guiding silica PCF with hydrogenated amorphous silicon (a-Si:H) inclusions. We will show that the resulting SiPCF guides light in the low loss core via the antiresonant reflecting optical waveguiding (ARROW) mechanism.