提出一种新的弱耦合三芯锥形光纤结构的应变传感器,该结构两端由薄芯光纤、中间由熔融拉锥三芯光纤构成,形成薄芯-三芯细锥-薄芯的三明治结构。实验研究了三芯长度和锥腰直径长度对传感器的应变与温度特性影响。结果表明:在0~1600 με应变范围内,传感器的干涉光谱随应变增大发生蓝移,当三芯光纤长度为7.4 cm,锥腰直径长度为41.20 μm时,其最大应变灵敏度为-3.47 pm/με,线性拟合度为0.9876;同时对温度传感特性进行探究,在25~60 ℃温度范围内,传感器温度灵敏度为34.52 pm/℃,线性拟合度0.9979。交叉敏感度为9.95 με/℃。该应变传感器具有成本低廉、结构简单、测量范围较大的优点,在工业生产、建筑监测等领域有潜在的应用价值。

A novel strain sensor based on a weakly coupled fiber structure with three tapered cores is proposed. This structure comprises two thin-core fibers and a tapered three-core fiber, in which the tapered three-core fiber is sandwiched between two thin-core fibers. The strain and temperature characteristics of the sensor were studied using various lengths of the tapered three-core fiber. The results show that the interference spectrum of the sensor is blue-shifted with increasing strain in the range of 0--1600 με. With a three-core fiber length of 7.4 cm and a cone diameter of 41.20 μm, the maximum strain sensitivity is -3.47 pm/με, and the linearity is 0.9876. At the same time, we also investigated the temperature sensing characteristics. In the temperature range of 25--60 ℃, the temperature sensitivity of the sensor is 34.52 pm/℃, and the linearity is 0.9979. The cross-sensitivity is 9.95 με/℃. The proposed sensor has the advantages of low cost, simple structure, and wide measurement range, and has potential applications in fields such as industrial production and construction monitoring.