Optical isolator
CA 2080904 A1 · Owner: Ishiguro, Youichi · Inventors: Shigematsu, Masayuki; Nishimura, Masayuki; Nakazato, Kouji
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical isolator for use in an optical communication system is independent of the plane of polarization of an incident beam and does not allow this plane to change on the outgoing side. The isolator comprises a first parallel flat double refractive crystal substance; a first Faraday rotor for rotating the plane of polarization of the beam; a second parallel flat double refractive crystal substance; a second Faraday rotor for rotating the plane of polarization in the direction opposite to that in which the first rotor rotated such plane; a third parallel flat double refractive substance; and permanent magnets for magnetizing the Faraday rotors. Since the Faraday rotors rotate the plane of …
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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 February 19, 1992. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended February 19, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 19, 2014.
- 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.