提出了一种新颖的基于虚拟仪器(VI)和可调谐激光技术的光纤光栅(FBG)传感系统,利用可调谐激光对由光纤光栅组成的传感器阵列进行波长扫描,实现了多根光栅的复用准静态解调,并结合抖动技术和反馈环结构,使得探测信号在每一根传感光栅中心波长处过零,以提高系统在测定波长偏移时的分辨力。当反馈环工作在闭环状态下时,该系统还可对单根光栅实现动态跟踪锁定,实现单根光栅的动态解调。该传感系统的数据采集采用虚拟仪器技术,通过多通道同时输入输出实现了在线实时解调。实验采用了4根光栅组成传感阵列,获得了静态多根光栅小于1 με和单根光栅动态频率10 Hz时3.3 nε/Hz的解调分辨力,动态应变范围在850 με。

A novel fiber Bragg grating (FBG) sensor system based on virtual instrument (VI) and tunable laser technology is proposed. The fiber wavelength sweep is made for Bragg grating sensor array by the tunable laser source and thus the quasi-static monitoring for multiple FBG sensors is realized. The system also combines dither technique and a feedback loop arrangement, produces a zero crossing at each of the FBG central wavelength and provides improved resolution in determining the Bragg wavelength shifts. The system can also operate in dynamic tracking mode to realize the dynamic demodulation of a single sensor. The data acquisition device introduces the VI technique and simultaneous multiple-channel input and output make the system perform the function of real-time monitoring. Four-element FBG sensors are adopted in the experiment and demodulation resolutions of less than 1 με and 3.3 nε/Hz at 10 Hz for static scanning mode and dynamic tracking mode respectively, are demonstated.