Abstract: A method of fabricating a structure from diamond material or diamond-like carbon material, and a structure according to the method, the method comprising the steps of imposing a structural transformation on the crystallographic structure of the material in a first region located at a first depth below a surface of the material; imposing a structural transformation on the crystallographic structure of the material in a second region located at a second depth below the surface of the material and above of the first region, the second depth being selected so that the first region is separated from the second region by a third region; and removing at least a portion of the material of the first and second regions; wherein the structural transformations are imposed so that the crystallographic structure of the third region is largely unaffected and the third region has opposite surface portions from which material of the first and second regions has been removed.

Abstract: An optical fiber being optically transmissive at a predetermined wavelength of light ? and comprising a plurality of coaxial layers. Each layer having an optical path length that varies radially, the coaxial layers being arranged to give the fiber a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fiber. The refractive index of a cladding region (60) is intermittently suppressed by controlling heating of the preform tube, thus forming a chirped saw-tooth profile (70). The optical fiber may include a lens. In this case, each of the layers has an optical path length that increases gradually outwardly by substantially n×?/2 (n: integer).

Abstract: The present invention provides a photon source comprising an optical waveguide and a material having at least one colour centre. The or each colour centre is arranged for photon emission and the material is grown so that the material is bonded to the optical waveguide and in use at least some of the photons emitted by the or each colour centre are guided in the optical waveguide. The present invention also provides a photon source having an optical waveguide incorporating the material which has the at least one colour centre.

Abstract: A method of fabricating a structure in a material.

Abstract: The present invention relates to a method of splicing together two optical waveguides, such as an optical fibre and a planar waveguide, or two optical fibres. The method involves the steps of etching a terminal end of an optical fibre in the manner so as to create a tapered core projection. Another optical fibre or waveguide has a complimentary recess etched therein. The projection and recess are placed together and the waveguides moved together to facilitate alignment of the respective cores of the waveguides. A tube etching method is utilised to create the projection.

Abstract: An optical fibre being optically transmissive at a predetermined wavelength of light &lgr; and comprising a plurality of coaxial layers. Each layer having an optical path length that varies radially, the coaxial layers being arranged to give the fibre a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fibre. The refractive index of a cladding region (60) is intermittently suppressed by controlling heating of the preform tube, thus forming a chirped saw-tooth profile (70). The optical fibre may include a lens. In this case, each of the layers has an optical path length that increases gradually outwardly by substantially n×&lgr;/2 (n: integer).