设计了一种基于相移光纤布拉格光栅(PSFBG)的应变传感器。将PSFBG和光纤布拉格光栅(FBG)通过光环形器连接在一起,并且沿着中线对称地粘贴在等强度悬臂梁上。两者共同作为探头的核心传感元件。它们粘贴的位置紧靠中线,从而承受着相同的应变,产生携带信息并且线宽极窄的传感光。通过边缘滤波法解调传感光,最终可以获取应变数值。理论模拟了由参数匹配的PSFBG和FBG产生的传感光谱,实验中获得了线宽仅为101 pm的传感光,实验结论与数值模拟吻合。在应变探头的实验验证中,解调结果与待测信号的线性关系良好,拟合度为0.994,探头的应变分辨率为1.5 με。基于该设计的应变传感器具有高分辨率、低成本、无啁啾等优点,具有很高的实用价值。
A novel strain sensor based on phase-shifted fiber Bragg grating (PSFBG) is designed. A PSFBG and a fiber Bragg grating (FBG) are connected together by an optical circulator, and symmetrically pasted on the uniform strength cantilever beam along the median. Both of them are the main sensing component of the strain probe. Because the location is next to the median, they have the same strain, and create sensing light which carries information and has extremely narrow line-width. Finally, the strain can be demodulated by an edge filter. The sensing light is got by theoretical simulation, and in experiment its line-width is only 101 pm. The experimental results are in good agreement with numerical simulation. In the experimental verification of strain sensor, the demodulation results have a good linear relationship with the signal to be measured. The fitting goodness is 0.994, and the resolution of strain probe is 1.5 με. The strain sensor based on this design is of high resolution and low cost, and is not chirped. It has a good practical value.