Applications of unconventional photorefractive materials in fibre optic devices

The photorefractive effect is a phenomenon in which the local index of refraction is changed by the spatial variation of the light intensity. Although the phrase 'photorefractive effect' has traditionally been used for such effects in electro-optic materials, unconventional materials, including photopolymers, holographic polymer dispersed liquid crystals (H-PDLC) and photosensitive glasses, have been developed in recent years and are playing increasingly important roles in optical fibre communication systems. Photonic devices made of these materials can easily be incorporated into an optical fibre system because of their low index of refraction and their relatively easy processing techniques. In this paper, we describe the applications of photopolymers, H-PDLCs and fibre Bragg gratings in fibre optic devices. Specifically, we will review our recent work on photonic devices such as filters, switches and dispersion compensators for WDM systems.