Process for the production of graded index optical fibres
US4249924A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 29, 1979 |
| Grant date | Feb 10, 1981 |
| Priority date | — |
| Expiry date | May 29, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C23/008
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for the manufacture of a glass blank in the form of a rod from which the optical fibre is drawn, said blank being produced starting from a molten bath of glass. A first stage of the process comprises melting a mixture of starting materials having a higher impurity content (<10.sup.-4) in the form of so-called transition metals then the final blank (<10.sup.-7). A second stage consists in inducing separation into two solid phases (a hard phase rich in silica and a soft phase poor in silica) by drawing the blank from the bath of molten glass and by subsequently subjecting it to a thermal annealing treatment. This is followed by deep etching and by peripheral etching to eliminate the soft phase and its impurities to different extents as a function of depth, which creates a radial refractive index gradient and an optical cladding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.