METHOD FOR MANUFACTURING OPTICAL FIBER PREFORM

PROBLEM TO BE SOLVED: To solve the problem that the appearance failure and the degree of eccentricity of a core are large because the surface temperature of a deposited soot or the density of a deposited soot layer is selected improperly in a method for manufacturing an optical fiber preform by reacting a raw material gas containing silicon in a flame mainly comprising gaseous oxygen and gaseous hydrogen to form the soot of silicon dioxide and depositing the soot layer comprising the soot on the surface of a glass rod. SOLUTION: The method for manufacturing the optical fiber preform comprises heating the surface of a glass body to 560-620°C, and at the same time, depositing an initial soot layer on the glass rod so that the deposit density of the soot layer of silicon dioxide becomes 0.8-1.5 g/cm3. Thereby, the optical fiber preform almost free from appearance failure can be obtained without making the degree of eccentricity large after drawing. COPYRIGHT: (C)2005,JPO&NCIPI