Heterodyne receiver for coherent optical communication
CA 2000997 C · Owner: Chikama, Terumi · Inventors: Onoda, Yoshihito; Kiyonaga, Tetsuya; Naito, Takao
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
After mixing the signal light and the local oscillattion light with a mixing circuit two, intersecting polarization components are divided by a polarization splitter and respective components are subjected to heterodyne detection by optical receivers. Thereafter, in an electric signal stage the intermediate frequency signal outputted from the optical receivers are applied to a 90-degree hybrid coupler and the output signal from one of the output ports is demodulated by a demodulator. On the other hand, an intermediate frequency signal outputted from the optical receivers are subjected to a subtraction to provide a principal axis angle monitor signal for the signal light. The signal …
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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 19, 1989 and granted February 8, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 19, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 19, 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
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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.