为了解决光纤传感器中普遍存在的温度和应变交叉敏感问题,基于少模光纤的模间干涉原理,研究了LP01和LP02模式干涉的应变和温度传感特性,详细分析了模间干涉传感的相位灵敏度理论。结合少模光纤的数值仿真结果,设计了一种温度不敏感的应变传感少模光纤,其纤芯直径为15.1μm,在1550nm下纤芯折射率为1.4512,包层折射率为1.444。搭建了实验系统来研究少模光纤温度和应变传感特性,结果表明:理论计算能够较好地预测实验结果;少模光纤在0~600μm范围内,应变的相位灵敏度为0.0196rad/μm,在30~330℃范围内,对温度不敏感,可有效改善温度和应变的交叉敏感问题。 In order to solve the cross-sensitivity problem of temperature and strain which are common in optical fiber sensors, the strain and temperature sensing characteristics of interference between LP01 and LP02 modes are studied based on the principle of inter-mode interference of a few-mode optical fiber. Sensitivity theory. A temperature-insensitive strain-sensing multimode fiber with a core diameter of 15.1μm and a core refractive index of 1.4512 at 1550nm and a cladding refractive index of 1.444 was designed based on numerical simulation of a few-mode fiber. The experimental system was built to study the temperature and strain sensing characteristics of the SMF. The results show that the theoretical calculation can predict the experimental results better. The phase sensitivity of the SMF is 0.0196 rad / μm in the range of 0 ~ 30 ~ 330 ℃ range, insensitive to temperature, which can effectively improve the temperature and strain cross-sensitive issues.