Noise reduction in optical communications networks
CA 2472322 C · Owner: Marconi Communications Limited · Inventors: Claringburn, Harry Richard; Sharratt, Michael
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The add path of a DWDM add/drop node comprises a n:1 coupler for combining n signal sources. The combined signal is amplified and then demultiplexed. Each output of the demultiplexer is passed through a variable optical attenuator (VOA) and the VOA outputs multiplexed to form the add signal. Channels carrying no add signal and not used to control the added signals are attenuated to zero to remove a broadband noise contribution from those channels. The signal sources are run at maximum power and the signal of those channels attenuated by the respective VOAs to control their amplitude and optimise the optical signal to noise ratio of the add signal.
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 17, 2002 and granted February 14, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 17, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 17, 2024.
- 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.