Optical fiber
CA 1236695 A · Owner: Northern Telecom Limited · Inventors: Abe, Koichi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract of the Disclosure A tubular porous silica preform is made by depositing particulate silica on a mandrel From which the preform is subsequently removed. A second 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 …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted May 17, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 17, 2005.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.