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为了提高光纤Bragg光栅(FBG)振动传感系统的解调灵敏度和解调范围,消除环境温度对解调信号的影响,设计了一种具有温度补偿功能的双匹配FBG振动传感系统。系统采用两个中心波长对称地位于传感FBG两侧的透射式匹配FBG,建立了两个互补对称的传感通道,并利用差分原理实现振动传感。通过Matlab软件对系统性能进行了仿真分析,结果表明,与传统方法相比,本文方法有效地提高了系统解调灵敏度和解调范围。将匹配FBG与热电制冷器(TEC)集成封装,并建立温度补偿判断通道,当判断通道输出电压超过已设置好的阈值时,利用TEC改变封装环境温度,使匹配FBG与传感FBG中心波长重新匹配,实现系统温度补偿。经实验测试,系统的归一化解调灵敏度为5.168/nm,解调范围为1.2nm,判断通道的归一化阈值电压为0.890 5。在4种不同环境温度下,利用本系统对同一振动信号进行测量,实验结果验证了系统温度补偿的可行性。
In order to improve the demodulation sensitivity and demodulation range of the fiber Bragg grating (FBG) vibration sensing system and eliminate the influence of ambient temperature on the demodulated signal, a double matching FBG vibration sensing system with temperature compensation was designed. The system uses two transmissive matching FBGs with symmetrical center wavelengths on the sensing FBGs. Two symmetrical sensing channels are established, and the vibration sensing is realized by the principle of difference. The performance of the system is simulated by Matlab software. The results show that compared with the traditional method, the proposed method effectively improves the system demodulation sensitivity and demodulation range. The matching FBG and thermoelectric cooler (TEC) are integrated and encapsulated, and a temperature compensation judgment channel is established. When it is judged that the channel output voltage exceeds the set threshold, the temperature of the packaging environment is changed by TEC to make the matching FBG and sensing FBG center wavelength re-set Match, to achieve system temperature compensation. The experimental test shows that the normalized demodulation sensitivity of the system is 5.168 / nm, the demodulation range is 1.2 nm, and the normalized threshold voltage of the channel is 0.890 5. In the four different ambient temperature, the system uses the same vibration signal measurement, the experimental results verify the feasibility of system temperature compensation.