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AssigneeTelstra Corporation Limited
InventorsKenneth Paul Clarke, David Coulson, Ernest Edward Gibbs, Barry John Keon, Alfred Willem Kruijshoop
Estimating the term…
A method and apparatus for inducing a localised optical transmission loss in an optical fiber cable is described, which is particularly well suited for use with optical time-domain reflectometry (OTDR) equipment to aid in locating faults in an optical fiber cable. A small portion of the optical fiber cable is cooled, such as by immersion in a cryogenic liquid like liquid nitrogen, and fibres in the cooled cable portion exhibit localised optical transmission loss which can be detected as a point loss (26) with the OTDR trace (24). The technique of inducing the point loss is non-invasive, and the localised transmission loss disappears when the cable portion returns to the ambient temperature, without damage to the cable.
A method for inducing a temporary localised transmission loss at a point along a telecommunications cable by temporarily cooling a portion of the telecommunications cable.
Apparatus for inducing a temporary localised optical transmission loss at a point along a telecommunications cable, comprising a cooling means for cooling a portion of the telecommunications cable.
A method for enabling identification of a position along a length of a telecommunications cable comprising cooling a portion of the telecommunications cable at said position to a temperature at which a point loss is observable on a time-domain reflectometer.
A method for locating a fault along a length of optical fibre cable comprising observing a fault loss resulting from the fault utilising optical time-domain reflectometry (OTDR), cooling a portion of the cable at a position along the cable length estimated from the observed fault loss to a temperature at which an induced point loss is observable, and locating the fault position by estimating the distance between the fault position and the position of the cooled cable portion utilising the observed OTDR fault loss and induced point loss.
Dependencies are inferred from the claim text.