Yi Duo, Liu Fei, Geng Youfu, Li Xuejin, Hong Xueming
Opt Express. 2021 Jun 7;29(12):18624-18633. doi: 10.1364/OE.428384.
Although numerous efforts have been dedicated towards developing fiber sensors with high performances, challenges still remain in achieving high-quality temperature sensors with high sensitivity, large measurement range and high stability. This study proposes a compact fiber optic temperature sensor based on PDMS-coated Mach-Zehnder interferometer (MZI) combined with FBG, and it can realize both high-sensitivity and large-range temperature measurement. The MZI is based on Thin No-Core Fiber (TNCF) with lateral-offset. Owing to the high refractive index sensitivity of MZI and the high thermo-optic coefficient of PDMS, the sensor can achieve a high temperature sensitivity (>10 nm/°C). Besides, by optimizing the TNCF length, the cascaded FBG can be used to locate different temperature intervals in units of approximately 10 °C, and therefore the detectable temperature range is largely extended. The experimental test demonstrates that the average sensitivities of 11.19 nm/°C, 8.53 nm/°C, 7.76 nm/°C, 7.27 nm/°C are achieved at the temperature around 30 °C, 40 °C, 50 °C and 60 °C, and it shows excellent consistency and repeatability during the thermal cycle tests.
尽管已经付出了诸多努力来开发高性能的光纤传感器，但在实现具有高灵敏度、大测量范围和高稳定性的高质量温度传感器方面仍然存在挑战。本研究提出了一种基于聚二甲基硅氧烷（PDMS）涂层马赫-曾德尔干涉仪（MZI）与光纤布拉格光栅（FBG）相结合的紧凑型光纤温度传感器，它可以实现高灵敏度和大范围的温度测量。该MZI基于具有横向偏移的细无芯光纤（TNCF）。由于MZI的高折射率灵敏度和PDMS的高热光系数，该传感器可实现高温度灵敏度（>10 nm/°C）。此外，通过优化TNCF长度，级联FBG可用于以约10°C为单位定位不同的温度区间，从而大大扩展了可检测温度范围。实验测试表明，在30°C、40°C、50°C和60°C左右的温度下，平均灵敏度分别达到11.19 nm/°C、8.53 nm/°C、7.76 nm/°C、7.27 nm/°C，并且在热循环测试中表现出出色的一致性和重复性。
