Abstract
Frequency characteristic of the optical fiber acoustic emission (AE) sensor integrating both of the sensing and the reference fibers into the sensing head for measurement in water was investigated. The characteristics of the sensor was evaluated by comparing the each waveforms detected by the optical fiber sensor and the PZT sensor having the known response function. It was demonstrated that no significant resonance is appeared in the range of 200 to 1200 kHz from the results of the experiment using the artificial AE source caused by pencil lead breaks. Dependence of the incidence direction of AE waves on the characteristics of the sensor was also discussed based on the experimental results using a cylindrical vessel. It was found that more flat characteristics is shown in the case of propagating AE waves toward the longitudinal direction of the sensor.
