Nonlinear optics in photonic crystal fibre: opportunities and challenges

In recent years we have pioneered the development of a new kind of optical fibre - photonic crystal (or "holey") fibre (PCF). In place of the usual cylindrically symmetric refractive index profile, peaking in the centre, PCF is formed from pure silica glass which is riddled with a regular lattice of air-holes typically sub-micron in diameter, spaced apart by a few microns.