Solid Photonic Bandgap Fibres and Applications

Abstract

We report on the development of optical fibres which guide light in a solid core using a photonic bandgap effect. The photonic bandgap cladding consists of a two-dimensional array of isolated high-index regions in a lower-index matrix, with a relatively low index contrast. The core is one or more unit cells of the matrix material without the inclusions. The frequency bands for photonic bandgap guidance can be predicted by considering the cut-off frequencies of the guided modes of the high-index rods in the cladding using the weakly-guiding approximation. We demonstrate the basic properties of such fibres and their use as a wavelength-selective element in a fibre laser cavity.