| 摘要 |
PURPOSE:To easily and optimally adjust the temp. of an optical fiber to be introduced into a hot CVD furnace by making the distance between a drawing furnace and the hot CVD furnace variable at the time of coating an optical fiber immediately after being drawn with an inorg. thin film in the hot CVD furnace. CONSTITUTION:The drawing furnace 1 for heating and melting an optical fiber preform 15, the hot CVD furnace 3 for coating the drawn fiber 16 with an inorg. thin film by thermochemical vapor growth method and a device 11 for measuring the outer diameter of the fiber, etc., are provided to constitute an inorg. coated fiber producing device, and further a position movement means 7 for varying the distance between the drawing furnace 1 and the hot CVD furnace 3 is furnished. The distance between the furnaces 1 and 3 is adjusted by the means 7 to adjust the fiber temp. at a place where a fiber is initially formed on the surface of the fiber 16 in the hot CVD furnace to 1000-1400 deg.C, the fiber 16 is coated with the inorg. thin film, and an inorg. coated optical fiber 17 is obtained. |
