环形光纤声发射传感器的相位调制特性研究

Frequency Response of Coiled-fiber Optic Sensor for Detection of the Acoustic Emission

提出了一种基于光纤Sagnac干涉仪的环形传感器,用于固体表面传播的超声波的检测.这种传感器的特点是能够精确地检测由固体表面传播的超声波产生的微弱振动.当超声波信号通过光纤传感器的两个臂到达探测器时,干涉仪的输出光强度受到了超声信号的调制.通过检测干涉仪的输出光强度并利用Fourier变换,测得了超声信号的振幅和频率.而且对传感系统的位相调制特性进行了仿真,并对实验结果进行了分析,结果表明该系统可用于固体表面传播的超声波频率特征的识别.

An coiled optical fiber sensor based on Sagnac interferometer for the measurement of ultrasonic wave propagated on the surface of a solid 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 solid plate transmission can be detected accurately. The output optical intensity of interferometer is modulated when the ultrasonic wave signal passes through the sensing coil of the Sagnac interferometer. The amplitude and the frequency of ultrasonic signal are obtained by using Fourier transform technique. Phase-modulation property of optical fiber sensor is discussed and experiment results are also analyzed,which shows that the system could be used to detect the ultrasonic frequency characteristics on the surface of the solid plate transmission.