Wavelength-division switching system for optical frequency-shift keying signals
CA 2008675 C · Owner: Nec Corporation · Inventors: Nishio, Makoto
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical switching system has an input terminal for receiving an optical wavelength-division multiplexed (WDM) signal in which optical signals differing in center wavelength .lambda.i (i = 1 to N) are wavelength-division multiplexed the, optical signal being an optical frequency-shift keying (FSK) signal which is a first optical FSK signal Fi. A splitter splits the optical WDM signal correspondingly to the wavelengths .lambda.i to generate optical wavelength-corresponding WDM signals Wi. Wavelength extracting circuits extract optical FSK signals Fj (j = 1 to N) pertaining to wavelengths .lambda.j, to which the wavelengths .lambda.i are to be switched from the, 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 January 26, 1990 and granted October 4, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 26, 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.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.