飞秒刻写光纤F-P腔级联FBG传感特性研究

Research on the cascaded fiber F-P cavity fabricated by femtosecond laser with FBG and its sensing characterization

提出了一种飞秒刻写光纤法布里-珀罗(F-P)腔级联切趾布拉格光纤光栅(FBG)的微结构传感器并研究了该传感器的温度与应变传感特性。该微结构传感器光谱稳定性良好,监测时长2 h内FBG波长最大漂移量为0.009 nm,功率最大漂移量为0.015 d B,F-P腔波长最大漂移量为0.018 nm,功率最大漂移量为0.072 d B。当应变由0με增至450με再减回0με时,该微传感器FBG特征峰先右移再左移,波长变化0.530 4 nm,应变灵敏度约1.17 pm/με,线性度高于0.99;光纤F-P腔特征谷波长变化0.491 1 nm,应变灵敏度约1.10 pm/με,线性度高于0.90。当温度由50℃升至200℃再降回50℃时,FBG特征峰先右移再左移,波长变化约1.418 nm,应变灵敏度约10.09 pm/℃,线性度高于0.95;光纤F-P腔特征谷波长变化约1.578 nm,应变灵敏度约10.53 pm/℃,线性度高于0.98。所提出的微结构传感器是解决单根光纤双参数测量的有效手段,同时对复杂环境下的多参数耦合测量与解耦也具有重要的参考价值。

A cascaded fiber Fabry-Perot （F-P） cavity fabricated by femtosecond laser with fiber Bragg grating （FBG） and its sensing characterization has been proposed and its temperature and strain sensing characterization has been studied. During two hours of stability test, the maximum FBG wavelength shift is 0. 009 nm, and the maximum FBG power drift is 0. 015 dB; the maximum F-P cavity wavelength shift is 0. 018 nm, and the maximum F-P cavity power drift is 0. 072 dB. When the strain is varying from 0με to 450 με then back to 0 με, the FBG wavelength peak is shifting towards right then left with the wavelength shift 0. 530 4 nm, and the strain sensitivity is 1.17 prn/ixa with linearity higher than O. 99; the F-P cavity wavelength shift 0. 4911nm, and the strain sensitivity is 1.10 pm/Ix~ with linearity higher than O. 90. When the temperature is varying from 50℃ to 200℃ then back to 50℃, the FBG wavelength peak is shifting towards right then left with the wavelength shift 1. 418nm, and the temperature sensitivity is 10.09 pm/℃ with linearity higher than 0.95; the F-P cavity wavelength shift 1. 578 nm, and the strain sensitivity is 10.53 pm/℃ with linearity higher than O. 98. This paper provides not only effective method to solve the problem of single fiber for double parameter but also reference value for the measurement of multi parameters coupling and decoupling in complex environment.