Optical switch
CA 2002098 C · Owner: Miyazawa, Hidehisa · Inventors: Miyazawa, Hidehisa; Yanagawa, Hisaharu; Kamata, Yoshiyuki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical switch includes at least one input optical semiconductor waveguide; two output optical semiconductor waveguides connected at a branch point to the input optical waveguide and diverging from the branch point with a preset angle .theta. (degree) therebetween; and a refractive index controlling section disposed in position on at least one of the output optical waveguides and apart from the branch point, for electrically pausing the refractive index of the output optical waveguide to be reduced. A light attenuating layer for preventing radiation mode light leaked from a portion near the branch point to the outside of the optical waveguide from being re-combined with guided mode light …
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 November 2, 1989 and granted January 11, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 2, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 2, 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.