Abstract: A method of manufacturing an optical fiber preform by passing a porous glass preform through a heating area in an atmosphere of dehydration gas to dehydrate the porous glass preform is provided. Values Pcl and V are set and dehydration is performed to satisfy 0.0773×e7.4873×??Pcl×T×L/V according to ?, T, and L, where Pcl is a partial pressure of chlorine gas in the dehydration gas, T is a process temperature, L is a length of an area in the heating area where a temperature is 1150° C. or higher, V is a relative moving speed of the porous glass preform with respect to the heating area, and ? is an average bulk density of a porous glass layer.

Abstract: A method of producing a porous glass preform for an optical fiber includes supplying glass material gas and combustion gas to a burner for synthesizing glass particles to produce glass particles, while relatively reciprocating the burner and a target rod that is rotating; and depositing the glass particles around the target rod. Density of the glass particles deposited per unit time ?c [g/cm3] is calculated. A sweeping speed of the burner S [mm/sec] is controlled to be decreased when the density ?c [g/cm3] is smaller than a target density ? [g/cm3] and to be increased when the density ?c [g/cm3] is larger than the target density ? [g/cm3].