| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus and method for sintering an optical fiber preform which, even when being a porous preform having a large outer diameter, has a uniform outer diameter in the longitudinal direction after sintering, does not need an outer-diameter adjustment work needed so far, can be subjected as it is to fiber drawing, and can lower its production cost. SOLUTION: The apparatus produces an optical fiber preform by sintering a porous preform 2 for an optical fiber to convert it into transparent glass. The apparatus has a function of detecting the amount of expansion and contraction of the preform 2 during sintering; this function is performed by a camera 20 for taking a photograph of the lower end of the preform 2 and an arithmetic unit 22 which analyzes the photograph to obtain the position of the lower end of the preform 2 and obtains the amount of expansion and contraction from the position of the lower end and the pull-down distance of the preform 2. The camera 20, for taking the photograph of the lower end of the preform 2, has a moving means 24 moving synchronously with the movement of the preform 2. COPYRIGHT: (C)2005,JPO&NCIPI
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