| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for sufficiently curing an ultraviolet curing resin applied on an optical fiber. SOLUTION: The optical fiber F coated with the ultraviolet curing resin by a die is introduced into a protective quartz tube 13 in a UV curing furnace 26. Cooling air is introduced into the UV-curing furnace 26 from an introducing tube 3 and discharged from an exhaust tube 4 so as to cool a UV lamp 1. At this time, the cooling air does not enter into the protective tube 13 because the absolute value of exhaust pressure is higher than the introducing pressure of the cooling air. Substantially oxygen-free gaseous nitrogen is supplied into an upper oxygen-free chamber 24 installed above the UV-curing furnace 26, and the gaseous nitrogen is supplied to the insides of a tube 23 and the protective tube 13, too. Thereby, the oxygen concentration of the atmosphere at the periphery of the optical fiber F is maintained to be≤1,000 ppm until the curing of the resin by irradiation with ultraviolet ray is completed. COPYRIGHT: (C)2004,JPO
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