METHOD OF PRODUCING SEMIFINISHED PRODUCT FOR DRAWING OPTICAL FIBRE

摘要

An improved method of producing an optical fiber with a low transmission loss for use in an optical communication system. The method comprises a chemical vapor deposition process wherein starting materials in gas phase are oxidized to form a soot on a glass substrate, and the soot which deposits on the substrate is vitrified in an atmosphere of an inert gas which is easily dissolved in the vitrified glass. A preferable soot contains silicon dioxide, a first dopant for effecting an increase of the refraction index of the silicon dioxide and a second dopant for effecting a reduction of the vitrification temperature of the soot.