Total internal reflection-type optical waveguide switch
CA 2080563 C · Owner: Yanagawa, Hisaharu · Inventors: Kamata, Yoshiyuki; Yanagawa, Hisaharu
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a total internal reflection-type optical waveguide switch which comprises optical waveguides crossing each other so that a refractive index changing region for developing a reflective surface is formed at a crossing section between the waveguides the refractive index changing region has a configuration such that the reflective surface constitutes a concave surface recessed with respect to one lateral portion of the crossing section. When the refractive index changing region is not activated incident light upon the spot corresponding to the reflective surface is insensitive to changes of the refractive index in the refractive index changing region, so that the initial crosstalk level can …
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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 14, 1992 and granted December 21, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 14, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 14, 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.