OPTICAL FIBER PREFORM, OPTICAL FIBER, AND METHOD FOR PRODUCING THE OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide an optical fiber preform which requires a smaller amount of heavy hydrogen and a shorter time of exposure to heavy hydrogen to give an optical fiber of improved hydrogen resistance and to provide an optical fiber produced therefrom.

SOLUTION: The optical fiber preform is one made from quartz glass and having a core region and a clad region surrounding the core region, wherein the ultraviolet transmittance in a 163 nm wavelength band is 30% or lower over the entire area of the optical fiber preform. The method for producing an optical fiber comprises making an optical fiber by spinning the optical fiber preform, subjecting the spun fiber to a heavy hydrogen exposure treatment by exposure to a heavy-hydrogen-containing atmosphere until the optical transmission loss in a 630 nm wavelength band becomes substantially zero to obtain an optical fiber of improved hydrogen resistance characteristics.

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