The Sagnac Interferometric Fiber Optic Acoustic Sensor And Its Positioning Technology

Fiber-optic acoustic sensors have received more and more attentions because of its excellences such as high sensitivity and anti-EMI. A novel fiber-optic microphone is introduced in this paper Based on Sagnac interference technology. The fiber-optic microphone is investigated theoretically and experimentally. A designed fiber-optic microphone system is realized and tested.Optical fiber acoustic sensing system which combines the fiber interference and fiber distributed sensing technology is one of the most ideal early-alarm technologies of communication fiber and pipe destruction. Based on the interferometer, the distributed fiber interferometer acoustic sensing system is regarded to be capable of any potential destruction of the fiber path. But its high precision locating technology should be developed further.Sagnac interferometer is converted into linear structure by using a new structure , which can overcome the loop shortcoming of traditional optical fiber Sagnac interferometer.This device was analyzed in theory and sound vibration was studied as an example in experiment. The experimental result accords with the theoretic analysis and the location accuracy is reach the target through signal treatment method such as phase demodulation, power spectrum and wavelet denoising , which shows that the novel device can realize the detection and location of the sound signal source .Because of the great needs of early-alarm and location of sound signal source, the research on this field has not only great science value but also potential social and economic benefits.