Abstract: Provided are a manufacturing method of an optical fiber base material and an optical fiber base material manufactured in the manufacturing method, the manufacturing method including: a process of combining at least two core base materials 70 by fusion-bonding to produce a single core base material; a process of fusion-bonding a pair of dummy glass rods 61 and 62 at both ends of the core base material 70 to produce a starting glass rod; a process of depositing, at an outer surface of the starting glass rod, glass particles generated by flame hydrolysis, to produce a porous base material 80; and a process of sintering and vitrifying, into transparent glass, the porous base material 80, to produce an optical fiber base material 310 that includes a core portion and a clad portion.

Abstract: Provided are a manufacturing method of an optical fiber base material and an optical fiber base material manufactured in the manufacturing method, the manufacturing method including: a process of combining at least two core base materials 70 by fusion-bonding to produce a single core base material; a process of fusion-bonding a pair of dummy glass rods 61 and 62 at both ends of the core base material 70 to produce a starting glass rod; a process of depositing, at an outer surface of the starting glass rod, glass particles generated by flame hydrolysis, to produce a porous base material 80; and a process of sintering and vitrifying, into transparent glass, the porous base material 80, to produce an optical fiber base material 310 that includes a core portion and a clad portion.

Abstract: A method of manufacturing a glass base material is provided. The glass base material according to the present invention can prevent an initial glass material from being scratched by a gripping portion and from being unfastened and can manufacture in a stable state without deflecting the initial glass material during depositing glass particles when the initial glass material is gripped by metal chucks, and the glass particle are deposited on the periphery of the initial glass material. A cushioning material of which surface has irregularity is intervened between the initial glass material and the gripping portion of a gripping device when the initial glass material is rotated with gripped by the gripping device and the glass particles are deposited on the periphery of the staring glass material. The cushioning material is preferably an elastic material having the thickness twice as long as the depth of the irregularity on the surface of the initial glass material.

Abstract: A method for manufacturing a porous-glass material for optical fiber performed in a reaction apparatus having a plurality of burners for producing glass particles toward a initial base material and a ventilation mechanism at a position opposed to the plurality of burners, the method comprises the steps of (a) moving the plurality of burners back and forth along a initial base material, (b) depositing the glass particles produced by the flame hydrolysis reaction of the glass raw material around the initial base material, (c) starting the deposition of a next porous-glass material without removing soot stuck to the inside of the chamber after the deposition of the glass particles is completed. Under the above condition, the inside pressure of the chamber is preferably adjusted within the range of ?80 Pa?Pmin??40 Pa, which is a pressure differential between the inside and outside of the chamber.