提出并研究了一种基于稀土光纤双花生结(RDDFP)的光纤温度传感器。采用稀土掺杂光纤制备双花生结,利用其包层模和纤芯模干涉对温度的敏感特性,结合稀土光纤中稀土离子的强热光效应,实现对温度的高灵敏度感知与测量。通过理论和实验研究并对比掺铒光纤双花生结(EDDFP)和掺镱光纤双花生结(YDDFP)两种稀土光纤花生结中的模式干涉和热敏感效应。实验结果表明,相比于普通光纤双花生结,RDDFP具有更强的热光效应和更高的温度灵敏度。其中,EDDFP温度灵敏度为1286 pm/℃,YDDFP温度灵敏度为-2343 pm/℃。基于RDDFP的光纤温度传感器具有灵敏度高、重复性高、全光纤、制作简单、结构紧凑等优势,在电力系统、建筑、航空航天以及海洋开发领域等具有良好的应用前景。

We proposed and demonstrated an optical fiber temperature sensor based on rare-earth-doped double-fiber peanut (RDDFP). We used fibers doped with rare-earth elements to fabricate a peanut-shaped structure that can realize high temperature sensitivity. The sensitivity of temperature to the cladding mode and core mode interference are used and the strong optothermal effect of rare-earth element ions is combined in the proposed structure. We have theoretically and experimentally investigated and compared the mode interference and thermosensitive effect of the erbium-doped double-fiber peanut (EDDFP) and ytterbium-doped double-fiber peanut (YDDFP). Experimental results show that comparing with a single-mode fiber peanut, RDDFP exhibits higher temperature sensitivity because of its stronger optothermal effect. The temperature sensitivity of EDDFP and YDDFP are 1286 pm/℃ and -2343 pm/℃, respectively. The optical fiber temperature sensor based on RDDFP has the advantages of high sensitivity, high repeatability, all fiber, simple fabrication, compact structure, and so on. It has good application prospects in the fields of power systems, architecture, aerospace, and ocean development.