基于半导体光纤环形激光器的光纤布喇格光栅动态应变传感系统

Dynamic Strain Sensor System Using Fiber Bragg Grating-Tuned Semiconductor Fiber Ring Laser

提出一种能实时识别外来撞击声发射信号的被动结构健康监测系统.此系统使用基于半导体光放大器的光纤布喇格光栅传感系统监测高频动态应变,动态应变引起的光栅反射谱波长移动转化为相位变化,并被迈克尔逊干涉仪解调.在迈克尔逊干涉解调仪中,使用PID控制器补偿由温度和大的准静态应变引起的低频漂移.对光程差和布喇格光栅光谱线宽等参量进行了分析和优化.利用该解调系统成功地对金属板受到撞击时激发的声发射进行了感测,可获取的动态应变信号频率高达197kHz.

A passive structural health monitoring system was presented for sensing foreign-object impact by using a semiconductor optical amplifier-based Fiber Bragg Grating （FBG） sensor that monitors high frequency dynamic strains. Strains applied on the FBG sensors were encoded as wavelength shifts of the light reflected by the FBG sensor which were then converted into phase shifts and demodulated by the Michelson interferometer. A Proportion Integration Differentiation（PID） feedback controller was employed to prevent interference drifting away from quadrature due to temperature and low frequency fluctuations. The adaptability of the demodulator and the optimum optical path difference were investigated. The impact signal from FBG dynamic strain sensor is acquired at the frequency up to 197 kHz.