Optical coupler/splitter with a filter
CA 2070264 C · Owner: Nakamura, Shiro · Inventors: Shimizu, Takeo; Ohyama, Isao; Yanagawa, Hisaharu
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical coupler/splitter having an optical waveguide on the side of light incidence two optical, waveguides on the branched side branched from the, former optical waveguide and each having straight and curved sections, and a dielectric multi-layer film filter provided in a manner crossing the latter waveguides and common to them. The filter is so formed as to intersect with a straight section of one waveguide and with a curved section of the other so, that respective crossing angles between the filter and the branched optical waveguides differ from each other, thereby providing different reflection or transmission characteristics with respect to the branched optical waveguides. An …
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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 2, 1992 and granted October 23, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 2, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 2, 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.