The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 10, 1981
Filed:
May. 29, 1979
Arnaud de Panafieu, Paris, FR;
Christiane Baylac, Paris, FR;
Yves Nemaud, Paris, FR;
Marc Turpin, Paris, FR;
Michel Faure, Paris, FR;
Thomson-CSF, Paris, FR;
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.