Mao Guopei, Yuan Tingting, Guan Chunying, Yang Jing, Chen Lei, Zhu Zheng, Shi Jinhui, Yuan Libo
Opt Express. 2017 Jan 9;25(1):144-150. doi: 10.1364/OE.25.000144.
Fiber Bragg gratings (FBGs) in a hollow eccentric fiber (HEF) have been proposed and demonstrated experimentally. The single-core and two-core HEF FBGs have been inscribed successfully using KrF excimer laser (248 nm), respectively. The temperature and axial strain sensing properties of the two samples have been measured. The experimental results indicate that the temperature and axial strain sensitivities of the two samples are similar, but they are smaller than that of conventional SMF-FBGs. Furthermore, the bending characteristics of the two-core HEF-FBG strongly depend on the bending direction due to the asymmetry of the fiber. Therefore, the proposed two-core HEF-FBGs facilitate temperature-compensated vector-bending sensing by measuring the difference between peak shifts of the two gratings. In addition, the two-core HEF-FBG can be a promising candidate for achieving two-channel filter since the signal crosstalk between the two cores can be largely eliminated by the central air hole.
空心偏心光纤（HEF）中的光纤布拉格光栅（FBG）已被提出并通过实验进行了演示。分别使用KrF准分子激光器（248 nm）成功写入了单芯和双芯HEF FBG。测量了两个样品的温度和轴向应变传感特性。实验结果表明，两个样品的温度和轴向应变灵敏度相似，但均小于传统单模光纤FBG的灵敏度。此外，由于光纤的不对称性，双芯HEF-FBG的弯曲特性强烈依赖于弯曲方向。因此，所提出的双芯HEF-FBG通过测量两个光栅峰值位移之间的差异，便于进行温度补偿矢量弯曲传感。此外，双芯HEF-FBG有望成为实现双通道滤波器的候选者，因为中心气孔可大大消除两芯之间的信号串扰。
