Fiber-Optic Michelson Interferometric Acoustic Sensor Based on a PP/PET Diaphragm

A novel acoustic sensor based on a polypropylene/poly (ethylene terephthalate) (PP/PET) diaphragm is demonstrated. The Michelson interferometer is formed by two beams of light that are reflected into optical fiber collimators by both sides of the PP/PET film. The deformation of diaphragm caused by acoustic signal will be magnified twice in the optical path of proposed sensor. The sensitivity of our proposed sensor is more than -128 dB re 1 rad/mu Pa in the frequency range of 90-4000 Hz, and a signal-to-noise ratio of similar to 42 dB is achieved at 600 Hz. Due to its superiorities of low cost, small size, high sensitivity, and easy fabrication, the proposed sensor exhibits a potential for low-frequency acoustic sensing and healthy monitoring.