VIBRATION AND IMPACT DETECTOR USING OPTICAL FIBER LOOP INTERFEROMETER

摘要

PROBLEM TO BE SOLVED: To provide a vibration and impact detector provided with a displacement detecting mechanism conformable to a large ground movement and hardly causing a problem even in a long-term maintenance. SOLUTION: This detector comprises the displacement detecting mechanism comprising first and second fulcrums arranged on the ground; a wire 21 having one end fixed to the first fulcrum; a rotating part 22 supported in the second fulcrum and having the other end of the wire wound thereon; excitation parts 22-2 mounted on the rotating part at a fixed pitch; and a resonant body 23 excited by one excitation part when rotating the rotating part and vibrated at a specified frequency, with part of a loop- shaped optical fiber 20 being in contact with the resonant body. When the space between the first and second fulcrums is extended, the wire is drawn out to rotate the rotating part. As a result, the vibration of the resonant body excited by the excitation part is converted to the vibration of the optical fiber, the change of interference light resulted therefrom is outputted from an optical fiber loop interferometer as a frequency signal, and the displacement of the space between the first and second fulcrums is determined from the generating frequency of the frequency signal.