| 摘要 |
A method of forming an optical waveguide (fibre) is disclosed which comprises depositing at a first temperature a silica soot layer 104 inside a substrate tube 106 using a gas flow of a silicon halide and oxygen, consolidating the soot layer at a second, higher, temperature in an environment of pure fluorine precursor gas to produce fluorine-doped cladding glass, and depositing a silica layer onto the cladding glass to provide a core glass 102. The silica core may be undoped silica or chlorine-doped silica. The substrate tube, cladding layer and core glass may then be collapsed to form a fibre perform. The substrate tube may be pure silica or fluorine-doped silica. The refractive index of the cladding glass may be lower (at least 0.008) than the refractive index of the core glass. Also disclosed are optical fibres having a core formed of silica or chlorine-doped silica and cladding formed of silica doped with fluorine (where the refractive index of the cladding glass is lower (at least 0.008) than the refractive index of the core glass), and those also having an outer cladding layer of silica or fluorine-doped silica. |
