Bending-induced colouring in a photonic crystal fibre

A photonic crystal fibre has been fabricated with a photonic crystal that is surrounded by a number of silica cores. Bending of the fibre induces an interaction between the core and photonic crystal areas, resulting in a highly wavelength-dependent loss of the core modes. White-light transmission experiments are presented which show that the colour of the transmitted light changes as a function of the fibre-bending radius. We compare the results to a simple model and find agreement.