基于布拉格光纤光栅谐振频率的实时测量

分析了一种基于布拉格光纤光栅(FBG)的高效方便的谐振频率检测系统。布拉格光纤光栅作为传感器粘贴在悬臂梁表面探测其振动,密集波分复用器(DWDM)作为波长解调器件通过透过率曲线获得布拉格光栅反射光的相对中心波长位移。通过计算机处理数据采集卡采集的实时信号获得悬臂梁多阶谐振频率。结果显示,在与传统的加速度传感器测量谐振频率进行比较时,两者结果很好地吻合。光纤光栅传感系统测得所需的1~4阶悬臂梁谐振频率在频谱上的信噪比均大于20 dB,系统的应力动态测量精度为2.45×10-9ε/Hz,表明该系统能够有效地测量谐振频率。

Real-Time Measurement of Harmonic Frequency with Fiber Bragg Grating

An efficient convenient harmonic frequency measurement system is reported in this paper. The vibration of cantilever is detected by a fiber Bragg grating (FBG) glued on the cantilever. The relative Bragg wavelength drift is demodulated by a dense wavelength division multiplexing (DWDM) based on its transmission rate curve. The real-time signal sampled by data-acquisition-card is processed by computer, and some orders of harmonic frequencies are obtained. The experiment shows that the measurement results of fiber Bragg grating agree with acceleration transducer. The signal-to-noise ratio of the frequency-domain signal reaches 20dB in 1～4 order harmonic frequency. The dynamic resolution reaches 2.45×10-9 ε/Hz. The result shows that the measurement system can efficiently measure the harmonic frequency.