Distributed feedback laser
CA 2049356 C · Owner: British Telecommunications Public Limited Company · Inventors: Westbrook, Leslie David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Improved single-modedness is achieved in distributed feedback (DFB) lasers by minimising the feedback provided at or near the ends of the DFB grating. The feedback may be minimised at one or both ends of the grating. Feedback is controlled by reducing the coupling to the grating. Coupling is reduced by reducing the depth of the grating's teeth and/or by increasing the spacing adjacent teeth.
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 April 2, 1990 and granted November 18, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 2, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 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.
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.