高速高分辨率光纤布拉格光栅传感系统的解调技术

Interrogation Technology for High-Speed and High-Resolution Fiber Bragg Grating Sensing System

提出使用基于半导体光放大器(SOA)的环形激光器与可调谐光纤型法布里-珀罗(F-P)滤波器作为扫描光源的光纤布拉格光栅(FBG)解调方案,综合使用梳状滤波器与乙炔气体的吸收谱进行谱线标定,采用数字信号处理算法进行时域滤波与3dB功率寻峰算法。实验证明,该解调方案可以同时实现对超过1000个温度FBG,或240个应变传感光栅进行解调,解调频率达到1000Hz,波长分辨率达到0.5pm,温度检测精度达到0.05℃,应变检测精度达到0.6με。

A new interrogation scheme based on semiconductor optical amplifier （SOA） ring laser and tunable Fabry- Perot （F-P） interferometer for fiber Bragg grating （FBG） sensing system is proposed. In the interrogation scheme, a gas absorption spectral line is used as a wavelength reference, and a comb filter is designed as a standard device that can dynamically calibrate the wavelength of FBG sensors. With digital signal processing technology and wavelength detection algorithm based on the 3 dB-power point, more than 1000 temperature sensors or 240 strain sensors can be interrogated with frequency of 1000 Hz. Experiment demonstrates that the strain measuring accuracy and wavelength resolution can reach to 0.6 μ∈ and 0.5 pm, respectively, and the temperature measuring precision can reach to 0.05 ℃.