Optical filter
CA 2176027 C · Owner: Poustie, Alistair James · Inventors: Finlayson, Neil; Poustie, Alistair James
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical filter comprises a multi-mode waveguide (W2) and a single-mode waveguide (W1, W3) coupled in series the, interference of different modes at the multiple-mode/single-mode interface being effective to filter an optical signal propagating through the waveguides to provide a desired wavelength response characteristic. The offset between the waveguides may be varied to control the filter characteristic. The filter may be formed in the cavity of a laser to produce an output having a comb-filter characteristic. It may be used as channel selector in WDM 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 November 11, 1994 and granted January 11, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 11, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 11, 2016.
- 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.