METHOD OF MANUFACTURING LARGE DIAMETER OPTICAL FIBER PREFORM AND APPARATUS FOR SINTERING GEL TUBE

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a large diameter optical fiber preform, by which the diameter deviation caused in the upper end and the lower end of a gel tube is made minimum.;SOLUTION: The method of manufacturing the large diameter optical fiber preform includes a mixing/dispersing process for mixing fumed silica with deionized water and forming a uniform sol by adding a dispersant, a molding process for pouring the sol into a mold having a predetermined shape, a process for converting the sol into gel, a demolding process for separating the gel formed in the mold from the mold, a drying process for drying the gel separated from the mold, an organic substance treating process for removing residual moisture in the dried gel, alkali metal impurities, and hydroxides, an insertion process for inserting and fixing a primary optical fiber preform into inside the gel subjected to these processes, and a sintering/over-cladding process for fitting the gel having the inserted primary optical fiber in a sintering apparatus and performing over-cladding while sintering the gel under a high-temperature vacuum atmosphere.;COPYRIGHT: (C)2004,JPO