Optical waveguide grating and production method therefor
CA 2319776 C · Owner: Yamauchi, Ryozo · Inventors: Sudoh, Masaaki; Nakai, Michihiro; Shima, Kensuke
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of producing radiative mode-coupled optical waveguide gratings that includes a step of irradiating an optical waveguide having a core composed of a material with a refractive index that changes when exposed to UV light. The UV light is generated by a UV beam and passed through a mask having slits for transmitting light at predetermined spacings while shifting the UV beam irradiation position along the core. During the UV beam irradiations which produce the grating portion, the optical waveguide and the mask do not move relative to each other.
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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 April 10, 1997 and granted February 25, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 10, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 10, 2019.
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Timeline
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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.