Theoretical and Experimental Investigation of the Bending Sensitivity of the D-shaped Fiber Bragg Gratings

用材料力学理论分析了D形光纤Bragg光栅(D-shaped fiber Bragg grating,D-FBG)以及常规光纤Bragg光栅由弯曲引起的轴向应变,得到了光栅Bragg波长漂移的弯曲敏感特性.实验结果和理论计算结果基本相符.与常规FBG相比,该D-FBG的弯曲灵敏度要高近80倍.因此D-FBG可以直接应用于弯曲形变的测量,以及间接应用于压力、加速度等物理量的测量.理论分析和实验结果对采用该类型光纤光栅的器件和传感系统的设计具有参考意义.The axial strain of D-shaped fiber Bragg grating(D-FBG) and normal fiber Bragg grating induced by bending was analyzed with mechanics of materials.Bending sensitivity characteristic of Bragg wavelength′s shift was obtained.Experiment result was in good agreement with the theory analysis.D-FBG′s bending sensitivity was about 80 times higher than normal circularly symmetrical FBG.The studied D-FBG can be directly applied in bending measurement,and indirectly in pressure or acceleration measurement.The theory analysis and experiment result was helpful for the design of device or sensor system using D-FBG.国家自然科学基金(60177026);; 福建省自然科学基金(0012-K32008)资