Recent progress in combining multiple materials with disparate optical, electronic and thermomechanical properties monolithically in the same fibre drawn from a preform is paving the way to a new generation of multimaterial fibres endowed with unique functionalities delivered at optical fibre length scales and costs. A wide range of unique devices have been developed to-date in fibre form-factor using this strategy, such as transversely emitting fibre lasers, fibres that detect light, heat or sound impinging on their external surfaces, and fibres containing crystalline semiconductor cores. Incorporating such fibres in future fabrics will lead to textiles with sophisticated functionality. Additionally, long-standing issues in traditional applications of optical fibres have been addressed by multi-material fibres, such as photonic bandgap guidance in hollow-core all-solid-cladding fibres and imparting mechanical robustness to soft-glass mid-infrared fibres. This paper reviews recent progress in this nascent, but rapidly growing field and highlight areas where growth is anticipated. Furthermore, the insights emerging from this research are pointing to new ways that the fibre drawing process may be leveraged as a fabrication methodology. In particular, recent efforts directed at appropriating multimaterial-fibre drawing for chemical synthesis and the fabrication of nanostructures such as nanowire arrays and structured nanoparticles are described.
