Branched optical fibre network loss detecting apparatus
CA 2004674 C · Owner: British Telecommunications Public Limited Company · Inventors: Keeble, Peter John
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
1. A method is described of detecting loss in a branched optical fibre network comprising a first optical fibre (1) and a plurality of second optical fibres (3) each of which is coupled to the first optical fibre. The first optical fibre (1) constitutes a main line, and the second optical fibres (3) constitute branch lines. A respective reflector (5) is associated with each of the branch lines (3). The method comprises the steps of launching a pulse into the main line (1) and monitoring the main line for changes in attenuation of reflected signals returning from the reflectors (5).
Read the whole patent
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 December 5, 1989 and granted March 4, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 5, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 5, 2011.
- 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.