Improvements in, or relating to, optical communications
CA 2432007 A1 · Owner: Bookham Technology Plc · Inventors: Griffin, Robert
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of transmitting a plurality n data streams comprises modulating an optical carrier using differential M-ary phase shift key (DMPSK) signalling in which M=2n.. Advantageously the method comprises using differential quaternary phase shift keying in which n=2. A particular advantage of the method of the present invention is that since the the data is differentially encoded in the form of phase changes rather than absolute phase values this enables the modulated optical carrier to be demolutated using direct detection without requiring a phase-locked local optical oscillator.The invention is particularly applicable to WDM communication systems.
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 December 18, 2001. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 18, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 18, 2023.
- 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.