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Expired Canadian patentCanada

Semiconductor heterointerface optical waveguide

CA 1306374 C · Owner: American Telephone And Telegraph Company · Inventors: Dentai, Andrew Gomperz; Joyner, Charles Howard Jr.; Alferness, Rodney Clifford

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Abstract From the Canadian patent

Low loss semiconductor waveguides for supporting propagation of optical signals over a wide range of wavelengths are achieved by growing at least two epitaxial layers of dopant material contiguous along a major surface of each layer to form a heterointerface therebetween. At least one of the epitaxial layers includes a sufficient concentration of semiconductor material to cause strain via lattice mismatch substantially at and near the heterointerface. The strain induces a change in refractive index such that the heterointerface exhibits a substantially higher refractive index than a portion of each epitaxial layer proximate to the heterointerface. The resulting waveguide is capable of …

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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

  • Granted August 18, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended August 18, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 10, 1988
GrantedAugust 18, 1992
Term endedAugust 18, 2009
Patent numberCA 1306374 C
Classification (IPC)G02B6/12 +2 more

Timeline

Timeline From CIPO dates

1989199219951998200120042007Application filedMay 10, 1988Patent grantedAug 18, 1992Term endedAug 18, 2009

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.