Tim is a Professor of Physics at the University of Bath. He is interested in how light travels along optical fibres, and in designing and making fibres so that the light travels in new and unusual ways. Examples include fibres that change along their lengths (eg tapered fibres), split and combine to form new waveguides (eg photonic lanterns), or incorporate patterns of air holes and other material variations across their structures (eg photonic crystal fibres and multi-core fibres). We gain understanding of these things by theory and simulations, and also by the use of our experimental facilities for fabricating fibres and post-processing them. This leads to benefits for applications such optical telecommunication, medical sensing and imaging, and astronomical instrumentation.