| 摘要 |
PURPOSE:To form a dense and uniform carbon coating film on the surface of an optical fiber by using a CVD reaction furnace constructed of a plurality of reaction tubes connected in series and connecting each reaction tube to an exhaust tube and a feed tube to feed a raw material compound which deposits a carbon coating layer by thermal decomposition. CONSTITUTION:A CVD reaction furnace 3 is constructed by connecting a plurality of reaction tubes 5 in series and connecting each reaction tube to an exhaust tube 8 and a feed tube 7 to feed a raw material compound (e.g. benzene) which deposits a carbon coating layer by thermal decomposition. An optical fiber preform is heated and spun in a spinning furnace 2 and the obtained bare optical fiber 1 is successively introduced into each reaction tube 5 of the CVD reaction furnace 3. At the same time, the raw material compound is introduced through the feed pipe 7 and heated with a heater 6 to effect the thermal decomposition and form a carbon coating film on the surface of the bare optical fiber 1. The carbon radical generated by the thermal decomposition of the raw material compound has short residence time in each reaction tube 5 and, accordingly, the polymerization of the carbon radical can be prevented. |
