A high sensitivity relative humidity sensor based on single mode tapered fiber (SMTF) structure coated with gelatin is reported. The sensing element is composed of a 12‐μm‐diameter fiber taper coated with a thickness of 26‐mm‐length gelatin layer, and is operated at a wavelength of 1550 nm. The sensor is designed based on the intermodal interference effect with high sensitivity (511.33 nW/%RH) and linear response for high RH (72‐90%RH) at 25°C. In this study, we analyzed the factors affecting sensor sensitivity and proposed the method to improve the sensitivity of the sensor. The sensor responses obviously. When the RH increased to more than 70%, the optical power boosts almost 10 000 times, which has promising potential applications as an optical switch in industrial production, food processing, and environmental early warning.

中文翻译：

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基于涂有明胶的SMTF结构的高灵敏度相对湿度传感器

据报道，一种高灵敏度相对湿度传感器基于涂有明胶的单模锥形纤维（SMTF）结构。传感元件由直径为12μm的光纤锥组成，并涂有厚度为26mm的明胶层，并在1550 nm的波长下工作。该传感器的设计基于在25°C时具有高灵敏度（511.33 nW /％RH）的多式联运干扰效应和高RH（72-90％RH）的线性响应。在这项研究中，我们分析了影响传感器灵敏度的因素，并提出了提高传感器灵敏度的方法。传感器响应明显。当相对湿度增加到70％以上时，光功率将提高近10,000倍，作为光开关在工业生产，食品加工和环境预警中具有广阔的应用前景。