Method of manufacturing optical fibre preforms
US4165224A · kind A · utility
21Cited by
0References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1978 |
| Grant date | Aug 21, 1979 |
| Priority date | — |
| Expiry date | Mar 17, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B2203/22
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In the manufacture of silica optical fibers a tube having an internal coating of a volatile dopant is locally heated by a hot zone repeatedly traversed along its length to promote shrinkage and finally collapse of the tube bore. During the shrinkage prior to the final collapse traversal a gas flow of oxygen and a halide of the volatile dopant is maintained through the tube in order firstly to provide a small overpressure to ensure circularity in the shrinkage and secondly to compensate for the tendency for dopant to be lost by volatilization.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.