A distributed Brillouin fiber sensor with centimeter spatial resolution has been employed for the measurement of small crack up to 1.5 cm. The out-layer damaged regions on an optical ground wire (OPGW) cable have been identified successfully by measuring the strain distributions every 5 cm. The stress increased to 127 kN which corresponds to more than 7000 micro-strain in the fibers. The locations of structural indentations comprising repaired and undamaged regions are found and distinguished using their corresponding strain data. The elongation of repaired region increases with time under 127 kN. These results are quantified in terms of the fiber orientation, stress, and behavior relative to undamaged sections.

© 2006 IEICE

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