Optical protection switch employing an interference filter
CA 2252209 C · Owner: Denkin, Nathan Myron · Inventors: Fishman, Daniel A.; Fang, Wei-Chiao William; Denkin, Nathan Myron
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A protection facility is provided for use in an optical communications node that communicates with another optical communications node via first and second bi-directional communications paths respectively serving as a service path and protection path, in which a filter filters signals respectivelyreceived over the service and protection paths and generates a main signal and a complementary signal for each of the paths. A control unit then generates a Loss of Signal (LOS_A) indication for the service path if a SUM signal or DIFF signal respectively derived as a function of a sum of the main and complementary signals generated for the service path and difference between the main and …
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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
- Filed October 29, 1998 and granted September 3, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 29, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 29, 2020.
- 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.