In recent years, the Brillouin Optical Time Domain Reflectometry (BOTDR) based optical fibre sensing technique has attracted great attention as a distributed monitoring method. Current BOTDR instruments are suitable for strain measurements over a certain distance (termed spatial resolution) .

The Brillouin optical time domain reflectometer(BOTDR) is a fiber optic strain and temperature distributed sensing system, which can measure strain and temperature along arbitrary regions of an optical fiber. If the optical cable is heated in certain part of the cable, and the temperature distribution curves along the fiber before and after the heating process are measured by the BOTDR, the corresponding heated point in the temperature distribution curves along the fiber can be identified by comparing the difference between the two curves. Since the location of the optical fiber fault also can be obtained by using the BOTDR, the distance between the faulty site and the heated site along the cable can be determined by reading the distance between the faulty site and heated site along the fiber.
Therefore, the optical cable fault location can be determined without related project documentation and complicated calculating. The accuracy of the fault location depends on the spatial resolution of the BOTDR and the distance between the heated site and the faulty site. The less distance there is, the more accurate the fault locating result is. We can increase the times of the heating process to decrease the distance between the heated site and the faulty one, and thereby obtain higher fault location accuracy.