Sol-gel process for the production of optical fiber preforms
AssigneeDegussa Novara Technology S.p.A.
InventorsLorenzo Costa, Fulvio Costa, Matteo Crepaldi
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Abstract
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 and densifying the dry gel to fully dense glass, wherein during the calcination treatment from 350° C. to 900° C. to remove organic impurities in the dry gel, it is carried out at least one reduced-pressure phase at a pressure comprised between about 0.01 and 0.5 bar.
Claims8
Sol-gel process for the production of optical fiber preforms or overcladdings comprising preparing a sol, allowing the sol to gel under high-speed rotation in order to obtain a cylindrical gel which is a wet gel, drying the wet gel to a dry porous gel by supercritical drying and densifying the dry porous gel to fully dense glass by thermal treatments, said densifying being a thermal treatment of calcination carried out under pure oxygen or a mixture of oxygen and an inert gas or gases, and during this calcination treatment the gel is subjected to at least one reduced-pressure phase, wherein said reduced-pressure phase at least 300 mbar below the atmospheric pressure.
Dependencies are inferred from the claim text.