理论和实验研究了基于游标效应的级联法布里珀罗干涉型传感器的温度特性, 该传感器是将一段空芯光纤熔接在两段单模光纤之间制作而成的, 其中空芯光纤的长度与末端单模光纤的长度相近.仿真结果表明：当温度升高时, 传感器的一些反射光谱向长波方向漂移, 而另一些反射光谱向短波方向漂移.分析结果可知, 光谱的移动方向和级联的两个法布里珀罗干涉仪的自由光谱范围的差值有直接关系,在温度升高的情况下, 自由光谱范围差值的正、负决定了传感器的光谱是向长波还是向短波方向漂移.此外, 自由光谱范围差值的大小对传感器灵敏度的高低起决定性作用, 其绝对值越小对应的传感器的灵敏度越高.实验制作了两个温度传感器, 其自由光谱范围之差分别为0.055 nm、－0.456 nm, 对应的温度灵敏度为163.8 pm/℃、－75 pm/℃, 实验结果与仿真结果一致.通过调整空芯光纤和末端单模光纤的长度可进一步提高灵敏度, 从而实现低成本、结构紧凑、高灵敏度的温度传感.

Optical fiber Cascaded FabryPerot Interferometers (CFPIs) sensors based on vernier effect were manufactured by splicing a segment of Hollow Core Fiber (HCF) between two segments of Single Mode Fiber (SMF), and its temperature characteristics were investigated theoretically and experimentally. Simulation and experimental results verify the phenomenon exists in CFPIs sensors, the interference spectra of some sensors based on vernier effect shift to longer wavelength while others shift to shorter wavelength when temperature increases. The phenomenon can be interpreted well based on the value D, which is defined as the Free Spectrum Range (FSR) difference of the cascaded FPIs. Under the condition that temperature increases, the positive or negative of D determines that the spectrum shifts towards longer wavelength or shorter wavelength. Besides, the investigation shows that D makes a great influence on temperature sensitivity. The temperature sensitivity improves with D decreasing. The temperature sensitivities of our experimental sensors are 163.8 pm/℃ and －75 pm/℃, which corresponding D are 0.055 nm and －0.456 nm, respectively. By optimizing the length of the HCF and the caudal SMF proportionally, a simple, compact, lowcost and highsensitivity CFPIs temperature sensor would be achieved.