Light communication system
CA 2044919 C · Owner: Shigematsu, Masayuki · Inventors: Nakazato, Kohji; Sankawa, Izumi; Shigematsu, Masayuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A bi-directional optical communication system. A first optical fiber includes a plurality of pieces, each piece having a first and second end. An optical amplifier for amplifying optical signals transmitted in a first direction is coupled to first and second pieces of the first optical fiber. A second optical fiber is coupled to the first and second pieces, bypasses the optical amplifier and transmits optical signals in a second direction opposite to the first direction. A first optical signal generator apparatus coupled to the first piece of the first optical fiber provides optical signals propagating in the first direction to a optical receiver apparatus coupled to the second piece of the …
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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 June 18, 1991 and granted June 11, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 18, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 18, 2013.
- 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.