METHOD FOR PRODUCING GLASS PREFORM FOR OPTICAL FIBERS

摘要

A method for producing a GeO2-SiO2, type glass preform for an optical fiber comprising dehydrating a porous soot preform of GeO2-SiO2 glass fine particles in an atmosphere of oxygen containing a fluorine-containing compound at such a temperature that the preform does not drastically shrink, and sintering the soot preform in an atmosphere comprising helium at such a temperature that the preform is made transparent, by which contamination with impurities, residual water and bubbles in the optical fiber and irregularity of the surface of the optical fiber are greatly reduced. Optical fibers may have a GeO2 distribution as shown in Figure 1.