Optical wavelength demultiplexer
CA 2015211 C · Owner: Nippon Telegraph And Telephone Corporation · Inventors: Matsumoto, Takao; Koga, Masafumi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical receiver including an optical conversion device which converts difference in wavelength into difference in spatial power distribution and pattern recognition element for recognizing patterns of the spatial power distribution and taking out output signals. At the output portion of the optical conversion device spatial power distributions are different for different wavelengths. After converting the spatial power distributions by the pattern recognition element into electric signals pattern recognition of the signals is performed to regenerate original signals with respective wavelengths. The optical conversion device uses a diffractive grating or a combination of an optical …
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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 23, 1990 and granted October 5, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 23, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 23, 2012.
- 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.