초록 ▼

Porous glass optical fiber preforms are conventionally formed by depositing many layers of glass soot on a mandrel, removing the mandrel, and heating the porous preform to form a consolidated glass article. To prevent the formation of a devitrified layer at the aperture-forming surface during the co

Porous glass optical fiber preforms are conventionally formed by depositing many layers of glass soot on a mandrel, removing the mandrel, and heating the porous preform to form a consolidated glass article. To prevent the formation of a devitrified layer at the aperture-forming surface during the consolidation step, the rate of soot deposition is initially reduced so that a stratum of fine soot is initially deposited on the mandrel. The stratum is initially discontinuous, but after a plurality passes of the soot-producing burner, it becomes continuous. Thereafter, the formation of the remainder of the soot preform continues in a conventional manner.

대표청구항 ▼

A method of forming a high purity glass article comprising the steps of: providing a substantially cylindrical mandrel, rotating said mandrel, directing at least a portion of a stream of glass particles toward said mandrel, reciprocatingly moving said stream longitudinally with respect to said mandr

A method of forming a high purity glass article comprising the steps of: providing a substantially cylindrical mandrel, rotating said mandrel, directing at least a portion of a stream of glass particles toward said mandrel, reciprocatingly moving said stream longitudinally with respect to said mandrel to build up a coating of said glass particles on said mandrel, removing said mandrel to form a tubular porous glass preform, and consolidating said porous glass preform to form a tubular glass article, the improvement comprising depositing the first plurality of layers of glass particles on the surface of said mandrel at a deposition rate that is sufficiently low that no spiral pattern of deposited glass particles is visible, whereby the aperture forming surface of said tubular glass article is free from devitrification. The method of claim 1 wherein the step of directing a stream of glass particles comprises providing a flame hydrolysis burner and feeding thereto a stream of oxygen and an amount of SiCl4 vapor no greater than that amount which would be entrained in a stream of oxygen bubbled at a rate no greater than 0.05 slpm through a reservoir of SiCl4 that is maintained at 37°C.