基于宽谱光源的光纤传感波长解调系统的研究

研究制作了基于宽谱光源的光纤传感波长解调系统, 以多光纤光栅作为波长参考基准、采用可调谐光纤法布里-珀罗(F-P)滤波器作为波长扫描器件。系统中采用三次多项式拟合的方法对滤波器锯齿波的扫描电压与透射波长关系曲线进行非线性拟合, 解决可调谐光纤F-P滤波器的电压—波长非线性关系对系统测量带来的较大误差问题, 实现波长的高精度解调。采用五光纤光栅做波长参考, 单根光纤光栅传感器的解调实验结果表明：待测光纤光栅布拉格波长短期测量分辨率为3.5 pm, 长期测量稳定性为7 pm。采用该系统对光纤非本征法布里-珀罗干涉型(EFPI)应变传感器的测试结果表明, 测量应变灵敏度为2.41 nm/με, 并且应变和波长之间存在良好的线性关系, 线性相关度达到0.99991。

Optical Fiber Sensor Wavelength Demodulation System Based on Broadband Light Source

Research work has been done in optical fiber sensor demodulation system based on broadband light source. Multi-FBGs are used as wavelength reference and fiber Fabry-Pérot tunable filter (FFP-TF) is used as wavelength selection device in the system. A non linear fitting based on cubic polynomial is adopted as the best fitting algorithm to convert scanned voltage of FFP-TF sawtooth wave to scanned transmission wavelength, which can solve the systemic error caused by the non linear relation between the wavelength and scanning voltage of FFP-TF, and then get higher demodulation resolution. In the experiment, five reference FBGs are used in the demodulation system. One FBG sensor demodulation result shows that wavelength resolution of measurement FBG is 3.5 pm for a short time, and long-term stability is 7 pm. An EFPI optical fiber strain sensor is tested with the demodulation system, which shows the strain sensitivity of 2.41 nm/με, besides, there is good linear relation between strain and wavelength with a linear correlation coefficient of 0.99991.