基于萨格纳克环级联光纤布拉格光栅的双参量传感器

Dual-Parameter Sensor Based on Sagnac Loop Cascaded with Fiber Bragg Grating

摘要:

设计了一种基于错位保偏光纤-少模光纤的萨格纳克环级联光纤布拉格光栅高灵敏度的应变和温度双参量传感器,并对应变和温度的传感特性进行了实验研究。通过将一段保偏光纤沿慢轴方向与单模光纤错位熔接,保偏光纤另一端与少模光纤熔接形成错位保偏光纤-少模光纤结构。然后将错位错位保偏光纤-少模光纤结构的两端连接到一个3 db光纤耦合器上,形成萨格纳克环路,萨格纳克环与光纤布拉格光栅级联形成基于错位保偏光纤-少模光纤的萨格纳克环级联光纤布拉格光栅的传感探头。实验结果表明,该传感探头中萨格纳克环的应变灵敏度可达19.14 pm/με,温度灵敏度可达-1.5 nm/℃,该传感探头中光纤布拉格光栅应变灵敏度为1 pm/με,温度灵敏度为10.8 pm/℃。该传感器具有较高的温度和应变灵敏度,可实现温度和应变的同时测量。

Abstract:

A high-sensitivity dual-parameter sensor for strain and temperature is designed based on a Sagnac loop cascaded with a fiber Bragg grating (FBG), utilizing a misaligned polarization-maintaining fiber (PMF) and few-mode fiber (FMF) structure. The strain and temperature sensing characteristics were experimentally investigated. The structure was achieved by splicing a section of PMF to a single-mode fiber (SMF) with a misalignment along the slow axis, and then splicing the other end of the PMF to an FMF to form a misaligned PMF-FMF structure. The two ends of this structure were connected to a 3 dB optical fiber coupler, forming a Sagnac loop, which was cascaded with the FBG to create a sensing probe. Experimental results showed that the strain sensitivity of the Sagnac loop in this probe can reach 19.14 pm/με, with a temperature sensitivity of -1.5 nm/°C, while the FBG strain sensitivity is 1 pm/με, with a temperature sensitivity of 10.8 pm/°C. This sensor exhibits high sensitivity to both temperature and strain