| 摘要 |
PURPOSE:To improve deposition efficiency of a carbon film and reduce formation of soot by preheating a bare optical fiber at a specific temperature and then growing a carbon film at a specific temperature by chemical vapor growth in forming the carbon film on the surface of the optical fiber according to a chemical vapor growth method. CONSTITUTION:A bare optical fiber 1, heated and spun in a spinning furnace 2 is passed on the center line of a preheating tube 4 of a preheating furnace 3 and fed so as to run at a prescribed linear velocity. A heating element 5 for preheating is then heated to heat the interior of the preheating tube 4 at a prescribed temperature and heat the bare fiber 1 at 1200-1500 deg.C. A hydrocarbon, etc., are fed into a reaction tube 7 of a CVD furnace 6 and heated with a heating element 8 for reaction to grow a carbon film at 600-900 deg.C on the surface of the bare fiber 1 by a chemical vapor growth method. The deposition of the carbon film is improved by the aforementioned method and formation of soot is simultaneously reduced. Thereby, an optical fiber having a carbon film of a sufficient film thickness formed thereon can be continuously produced at a high speed for a long period. |
