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:
Mar. 10, 1987
Filed:
Apr. 08, 1985
Koichi Abe, Ottawa, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A tubular porous silica preform is made by depositing particulate silica on a mandrel from which the preform is subsequently removed. A solid cylindrical porous silica preform is made by depositing particulate silica on an end surface of a support body. The porous preforms are then dried and the tubular preform is heated in a fluorine containing atmosphere to introduce a fluorine dopant into the silica. The rod preform is then placed inside the tubular preform and the two preforms are further dried in a chlorine atmosphere to remove residual moisture. The dual preforms are then heated in a zone sintering furnace to consolidate and collapse the porous material of the rod and tubular preforms into a transparent fused silica rod. The composite preform obtained is heated and dielectric optical waveguide drawn from it, the waveguide having a pure silica or doped silica core derived from the rod preform and a fluorine doped silica cladding derived from the tubular preform.