| 摘要 |
PURPOSE:To obtain a high-strength product excellent in hydrogen resistance characteristics by using a halogenated hydrocarbon having all H atoms in the molecule substituted with halogen atoms as a raw material in forming a carbon film on the surface of an optical fiber by a chemical vapor growth method. CONSTITUTION:A bare optical fiber 1 is passed on the central axis of a heating furnace 3 and fed so as to run at a prescribed linear velocity. A heating element 5 is then heated to heat the interior of a reaction tube 4 at a prescribed temperature. A halogenated hydrocarbon, e.g. CF4 or CClF3, is simultaneously fed from a raw material compound feeding tube (4a) into the interior of the reaction tube 4. The CF4, etc., are then thermally decomposed to form a carbon film on the surface of the bare fiber 1. Since water molecules adsorbed on the surface of the bare fiber 1 can be removed in forming the carbon film by the above-mentioned method, silanol groups corroding the fiber surface can be prevented from forming and the resultant optical fiber has high mechanical strength. Furthermore, treatment can be carried out at a high speed due to facilitated deposition of the carbon film. |
