| 摘要 |
PURPOSE:To eliminate fluorine-removed defect, etc., and obtain fluoride optical fiber having high strength by hot-draw-spinning base material for fluoride optical fiber and introducing the surface of glass into halogen-compound gas or foggy liquid atmosphere immediately after drawing or spinning. CONSTITUTION:Base material 1 of fluoride optical fiber is set in a core tube 3 of drawing furnace and gas for drawing atmosphere (e.g., N2 gas) is supplied from gas-feeding port 5, then heated at drawing temperature by heater 4 with discharging through discharging port 6, thus drawn to form optical fiber. Next, said fiber is introduced into halogen-based gas (e.g., F2 or NF2) supplied from halogen-based gas supplying port 7 and discharged through discharging port 8 and passed. By said method, fluorine-removed defect existed before drawing or spinning process, or fluorine-removed defect or hydroxide apt to be generated in hot-drawing or spinning, etc., is able to be eliminated and factor of optical fiber breaking is able to be suppressed. |
