The method of manufacturing an optical fiber

PROBLEM TO BE SOLVED: To provide a method for producing an optical fiber at a reduced manufacturing cost by making the large-size optical fiber without using expensive helium gas. SOLUTION: The method comprises the cylindrical porous body making step S1 of making a cylindrical porous body 9C by depositing glass microparticles around the circumference of a mandrel and pulling the mandrel out, the dehydration step S2 of dehydrating the porous body 9C under at least one condition of a vacuum, an inert gas/halogen gas atmosphere, and an inert gas/halogen compound gas atmosphere, the sintering step S3 of sintering the dehydrated porous body 9C in a vacuum into a translucent glass cylinder 9B containing closed cells, the core rod insertion step S4 of inserting a core rod 7A into the translucent glass cylinder 9B, and the drawing step S5 of drawing the resultant assemblage under heating so as to integrate the core rod 7A and the translucent glass cylinder and so as to transparentizing the translucent glass cylinder 9B into a transparent glass. COPYRIGHT: (C)2006,JPO&NCIPI