Frequency response of coiled-fiber optic sensor for detection of the acoustic emission
环形光纤声发射传感器的相位调制特性研究

An coiled optical fiber sensor based on Sagnac interf erometer for the measurement of ultrasonic wave propagated on the surface of a s olid plate has been proposed and demonstrated. The advantage of this kind sensor is that the feeble vibration produced by ultrasonic wave on the surface of soli d plate transmission can be detected accurately.The output optical intensity of interferometer is modulated when the ultrasonic wave signal passes through the s ensing coil of the Sagnac interferometer. The amplitude and the frequency of ult rasonic signal are obtained by using Fourier transform technique. Phase-modulat ion property of optical fiber sensor is discussed and experiment results are als o analyzed,which shows that the system could be used to detect the ultrasonic fr equency characteristics on the surface of the solid plate transmission.