Patent ID: 7136559

Claim:
An optical fibre device which, in use, utilises the Raman effect, comprising: a holey optical fibre with a structure which allows the fibre to guide the light at a first wavelength and a second longer wavelength and which results in energy transfer of light at the first wavelength propagating in the fibre to the second wavelength by the nonlinear optical process of Raman scattering within the fibre such that the ratio of optical power within the fibre at the second wavelength to optical power within the fibre at the first wavelength is increased, the holey optical fibre being fabricated from a first material and having a core region doped with a dopant that gives the holey optical fibre a higher nonlinearity than the first material; a first optical source operable to emit light at the first wavelength with a first power level; and a coupler operable to couple light from the first optical source into the holey optical fibre so that the light undergoes Raman scattering.