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Expired Canadian patentCanada

Method of measuring the refractive index profile of optical fibers

CA 1286403 C · Owner: Sumitomo Electric Industries, Ltd. · Inventors: Buckland, Eric L.; Nishimura, Masayuki; Hatton, William H.

CIPO record

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Abstract From the Canadian patent

The present invention is directed to a method for determining the refractive index profile of an optical fiber wherein light from an intense optical source is focused at the bare fiber end portion of the test fiber. A small amount of light will be coupled into the optical fiber where for the short length of uncoated fiber only cladding modes are excited. The index of refraction is determined directly by analyzing the intensity distribution emitted from the optical fiber with a lens system having a limited numerical aperture.

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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 July 16, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 16, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledSeptember 8, 1987
GrantedJuly 16, 1991
Term endedJuly 16, 2008
Patent numberCA 1286403 C
Classification (IPC)G01M11/00 +1 more

Timeline

Timeline From CIPO dates

1988199119941997200020032006Application filedSep 8, 1987Patent grantedJuly 16, 1991Term endedJuly 16, 2008

Sources & verification

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