Acoustic vibration sensor based on macro-bend coated fiber for pipeline leakage detection

In this paper, a simple fabricated and low cost acoustic vibration sensor based on macro-bend coated single-mode fiber (SMF-28) is proposed and developed. The fiber optic sensor comprises of a bending structure and the macro-bending loss was employs as the sensing mechanism for the detection of leakage of pipeline at low frequency. The measurement system involving the proposed fiber sensor is presented and investigated. Through this system, the fiber sensor is characterized by measuring the power loss corresponding to the vibration at various bending radius and number of wrapping turns. Furthermore, the proposed fiber sensor is also implemented in field test (water pipeline) and it is able to detect vibrations at the frequency range of 20 Hz to 2500 Hz.