The occasion where it forms 1st clad in the aforementioned core production manner and the optical fiber basic material and optical

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical fiber preform which is capable of preventing the generation of multiple cracks entering the preform surface when depositing porous glass particulates for a second clad on a first clad having a deformed section, the optical fiber preform free of defects and an optical fiber having a high excitation efficiency of exciting light. ;SOLUTION: The method for manufacturing the quartz optical fiber preform having at least a core, the first clad and the second clad is the method for manufacturing the optical fiber preform having the deformed first clad which has a stage for deforming the cross-sectional shape of the first clad to a shape having a straight portion in at least one point in forming the first clad to the core, and a stage for depositing the porous glass particulates of the same material as the material of the first clad as the second clad on a glass rod having the deformed first clad to form the porous glass optical fiber preform and forming the second clad having a circular cross section by vitrifying the same.;COPYRIGHT: (C)2001,JPO