FABRICATION METHODS OF DOPED SILICA GLASS AND OPTICAL FIBER PREFORM BY USING THE DOPED SILICA GLASS

摘要

Manufacturing method of doped silica glass suitable for optical fiber wherein quartz powder or SiO2 glass fine particles are exposed to a gas for producing the doped silica glass containing SiCl4, a gaseous additive and water vapor (H2O) to add the dopant to the glass body, and then the resulting glass body is fused at a high temperature, thereby producing a transparent doped silica glass in which the production of the glass particles, the addition of the dopant, and the vitrification of the glass body are carried out by separate steps under respective suitable conditions. The manufacturing speed is remarkably increased because of the separate steps. Content of dopant is not limited, but can be adjusted with any desired amount by changing a reaction time of dissolution. Dopant components like PbO2, SnO2, ZnO which is hardly added to the glass body can be added. Manufacturing method of optical fiber preform wherein the doped silica glass is deposited and fused on a starting material which is inclined by an angle within a range of 5 - 90.degree. with respect to a blow-off direction of the flow of the doped silica glass to form a transparent doped silica glass body having a uniform outer diameter and a uniform boundary surface at a high synthesizing speed. This aids mass production of optical fiber at a low cost.