METHOD OF MANUFACTURING OPTICAL FIBER PREFORM AND OPTICAL FIBER PREFORM

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical fiber preform by which the deformation or the strain of a circular opening is reduced in the method of manufacturing the optical fiber preform having the circular opening extending in the longitudinal direction. SOLUTION: In the method of manufacturing the optical fiber preform having the circular opening extending in the longitudinal direction by depositing glass fine particles on the outer circumferential part of the glass preform having the circular opening extending in the longitudinal direction to synthesize a porous glass and sintering, a pipe member is connected to one end or both ends of the glass preform and the hollow part of the pipe member and the circular opening of the glass preform communicate with each other to open the circular opening to the atmosphere before a process for depositing the glass fine particles and a process for sintering the porous glass. The pressure inside the circular opening of the glass preform is controlled to (the atmospheric pressure)+0.0 kPa to +5.0 kPa and the circular opening of the glass preform is sealed by connecting a solid member to both end of the glass preform before the process for depositing the glass fine particles and the process for sintering the porous glass. The bulk density of the glass fine particle deposited on the glass preform is controlled to 0.4-0.8 g/cm3. COPYRIGHT: (C)2004,JPO&NCIPI