Identification and location of fiber optic cables
AssigneeRadiodetection Limited
InventorsStuart John Russell, Andrew Biggerstaff Lewis, John Philip Dakin
Life of this patent
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Abstract
In order to identify a fiber optic cable (10) a beam (14) of polarised light is caused to pass down the cable to a first site (A) at which an electromagnetic field (24) is applied to the cable (10). The electromagnetic field (24) traverses the cable (10) in an essentially transverse direction and has a time-varying component orientated along the length of the cable (10) at the first site (A), with the component varying so that the line integral thereof along the cable (10) is non-zero. This results in a variation in the polarisation of the light, which can then be detected by a polarisation discriminator (20) at a second site (B), thereby to identify the cable (10).
Claims20
An apparatus for identifying a fibre-optic cable, comprising:
- an optical detector, connected to said cable, to detect a modulation applied to a beam of light, travelling on said cable, emitted from a remote light source with a predetermined polarization, said modulation of said beam comprising a variation in said polarization of said beam received from said cable caused by the application, at a remote location, of a transverse electro-magnetic field having a time varying component with non-zero line integral orientated along the light path of said cable;
- and
- an output circuit, connected to said detector, to output signals indicative of the detected variation of polarisation.
An apparatus for identifying a fibre-optic cable, comprising a detector to detect one or more modulations applied to a beam of light carried on said cable and emitted from a remote light source with a predetermined polarization, said modulation of said beam comprising a variation in said polarization of said beam received from said cable caused by the application, at a remote location, of a transverse electro-magnetic field having a time varying component with non-zero line integral orientated along the light path of said cable, and to output signals indicative of the detected variation of polarisation.
An apparatus for identifying a fibre-optic cable, comprising:
- optical detecting means for detecting a modulation applied to a beam of light, travelling on said cable, emitted from a remote light source with a predetermined polarization, said modulation of said beam comprising a variation in said polarization of said beam received from said cable caused by the application, at a remote location, of a transverse electro-magnetic field having a time varying component with non-zero line integral orientated along the light path of said cable;
- and
- outputting means, connected to said detecting means, for outputting signals indicative of the detected variation of polarisation.
A method of identifying a fibre-optic cable comprising:
- detecting a modulation applied to a beam of light emitted from a remote light source with a predetermined polarization, said modulation of said beam comprising a variation of said polarisation of said beam caused by application, at a remote location, of a transverse electro-magnetic field having a time varying component with non-zero line integral orientated along the light path of said cable, and outputting signals indicative of the detected variation in polarisation.
Dependencies are inferred from the claim text.