GLASS POROUS BODY FOR MANUFACTURING OPTICAL FIBER, ITS MANUFACTURING METHOD, OPTICAL FIBER PREFORM, ITS MANUFACTURING METHOD, METHOD FOR CERTIFYING DEHYDRATION OF OPTICAL FIBER PREFORM, AND METHOD FOR MANUFACTURING OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To provide: a glass porous body for manufacturing an optical fiber, with which the dehydration state of a preform can be surely certified in a short time without breaking the preform; a method for manufacturing the same; an optical fiber preform; a method for manufacturing the same; a method for certifying the dehydration of the optical fiber preform; and a method for manufacturing the optical fiber. SOLUTION: The glass porous body for manufacturing the optical fiber is characterized in that it has a deposited layer, formed by the deposition of glass fine particles formed by a vapor phase method and having a bulk density of≤1.4 g/cm3, and a marker layer, formed of glass fine particles having the same composition within a thickness range of≤10 mm and having bulk density varied by at least 0.4 g/cm3in the bulk density distribution in the thickness direction, exists at least one part in the deposited layer. COPYRIGHT: (C)2007,JPO&INPIT