Apparatus and method employing polarization modulation to reduce effects of polarization hole burning and/or polarization dependent loss
CA 2127043 C · Owner: American Telephone And Telegraph Company · Inventors: Heismann, Fred Ludwig
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The effects of polarization dependent hole burning and/or polarization dependent loss are reduced by modulating the state of polarization (SOP) of an arbitrarily polarized optical signal being launched into the transmission path periodically through a predetermined sequence of polarization states. The sequence of polarization states is selected such that on average the launched modulated signal excites substantially all possible polarization states with substantially equal probability, independent of the input SOP to the polarization modulator. In one exemplary embodiment, the SOP is modulated by a combination cascade of a rotating half-wave plate followed by a quarter-wave plate which …
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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 June 29, 1994 and granted June 16, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 29, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 29, 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.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.