Research of acoustic sounding sensors over obstructs based on reflective intensity modulated fiber-optic sensor

Reflective intensity modulated fiber-optic sensors (RIM-FOS) have received increasing attention in the fields of civil engineering for their superior ability of explosion proof, immunity to electromagnetic and high accuracy, especially fitting for measurement applications in harsh environment. A novel functioning prototype of an integrated sensor based on RIM-FOS which is used for acoustic sounding over obstruct is introduced. It aims at the integration of optical fibers based sensors into functional probe for extending the capabilities of the portable solutions for the acoustic detection over solid obstructs. According to the laws of wave propagation, the mechanism of acoustic wave transmission between solid medium and acoustic sounding probe is studied and the calculating formula reflecting the wave transfer process was presented. Some details and overview regarding our ongoing efforts are provided. The experimental results show that the developed sensor's response distortions towards 1 kHz 94 dB sound pressure level (SPL) signal are all lower than 8% in 4 experimental terms including 5 cm wood board, 5 cm concrete prefabricated board, 12 cm brick well and 10 cm concrete prefabricated board.