In recent years, two new types of optical fibre have revolutionised this dynamic field, bringing with them a wide range of novel optical properties. These new fibres, known collectively as microstructured fibres, can be made entirely from one type of glass as they do not rely on dopants for guidance. Instead, the cladding region is peppered with many small air holes, that run the entire fibre length. These fibres are typically separated into two classes, defined by the way in which they guide light:
Holey fibres, in which the core is solid and light is guided by a modified form of total internal reflection as the air holes lower the effective refractive index of the cladding relative to that of the solid core.
Photonic band-gap fibres, in which guidance in a hollow core can be achieved via photonic band-gap effects. The many varieties of microstructured fibres are discussed in more detail in the following sections.
Within the group we have the full range of expertise required to design, fabricate and characterise both forms of microstructured fibre, both in silica and in compound glass. We also run a large number of end application projects both in close collaboration with a range of other ORC groups, and with other external academic and industrial partners. Current collaborating organisations include amongst others: ETH Zurich, University of Dijon, Cambridge University, Mullard Space Centre, SPI Lasers Ltd, Furukawa, Hovermere Ltd, BAe Systems and SELEX.