| 摘要 |
A method of forming a preform or blank for an optical filament, the preform itself and the resulting optical filament is disclosed. The preform is formed by providing a substantially longitudinally continuous core member and affixing it to a starting member. Particulate material is applied to the exterior surface of the core member to form an adherent coating having an index of refraction less than that of the core member. The starting member and the core member are longitudinally translated while simultaneously applying the adherent coating of particulate material to the core member to form a continuous and substantially homogeneous adherent coating of substantially uniform thickness. The composite so formed is simultaneously or subsequently heated to sinter or consolidate the applied adherent coating thereby forming a solid blank which may be heated to the drawing temperature of the material thereof and drawn to reduce the cross-sectional area thereof forming a substantially continuous optical waveguide, the core member comprising the core while the consolidated coating comprising the cladding of the optical waveguide. The adherent coating may be sintered or consolidated to form a solid blank and thereafter drawn in a separate operation or subsequently drawn as part of a continuing operation. As an alternate, the optical waveguide may be drawn immediately following the sintering or consolidation step employing a single heating of the structure.
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