Sol-gel process for the production of glass optical fiber preforms

摘要

Sol-gel process for the production of optical fiber preforms or overcladdings by preparing a sol, gelling the sol, drying the wet gel to a dry porous gel by supercritical drying and densifying the dry gel to fully dense glass, wherein during the calcination treatment from 350 DEG C to 900 DEG C under pure oxygen or a mixture of oxygen and an inert gas or gases to remove organic impurities in the dry gel, at least one reduced-pressure phase at a pressure comprised between about 0.01 and 0.5 bar is carried out.