A sensitive tapered optical fiber sensor incorporating graphene oxide (GO) and polyvinyl alcohol (PVA) composite film for the rapid measurement of changes in relative humidity was proposed and experimentally demonstrated. The sensing principle was based on the intensity modulation of the transmitted light induced by the refractive index changes of the sensitive coatings. The sensing region was obtained by tapering a section of single-mode optical fiber (SMF) from its original 125 µm diameter down to 9.03 µm. The tapered structure was then modified through deposition of GO/PVA nanocomposites by using the dip-coating technique. The field emission scanning electron microscope (FESEM) and Raman spectroscopy were used to characterize the structure of the composite film. As evidenced by a Fourier transform infrared spectroscopy (FTIR) analysis, the presence of oxygen functional groups (such as −OH and COOH) on the GO structure enabled the attachment of PVA molecules through hydrogen bonding and strong adhesion between GO/PVA layers. The performance of the sensor was tested over a wide range (20%RH to 99.9%RH) of relative humidity. The sensor showed a good response with its signal increasing linearly with the surrounding humidity. The tapered optical fiber sensor with the coating of GO/0.3g PVA achieved the highest sensitivity [0.5290RH (%)]. The stability, repeatability, reversibility, as well as response time of the designated sensor were also measured and analyzed.

提出并结合了氧化石墨烯（GO）和聚乙烯醇（PVA）复合膜的灵敏锥形光纤传感器，用于快速测量相对湿度的变化。感测原理基于由敏感涂层的折射率变化引起的透射光的强度调制。通过将单模光纤（SMF）的一部分从其最初的125 µm直径减小到9.03 µm的锥度来获得感测区域。然后使用浸涂技术通过沉积GO / PVA纳米复合材料来修饰锥形结构。利用场发射扫描电子显微镜（FESEM）和拉曼光谱对复合膜的结构进行表征。傅立叶变换红外光谱（FTIR）分析证明，GO结构上存在氧官能团（例如-OH和COOH）可通过氢键和GO / PVA层之间的牢固粘合使PVA分子附着。在较宽的相对湿度范围（20％RH至99.9％RH）下测试了传感器的性能。传感器显示出良好的响应，其信号随周围湿度线性增加。带有GO / 0.3g PVA涂层的锥形光纤传感器具有最高的灵敏度[0.5290RH（％）]。还测量并分析了指定传感器的稳定性，可重复性，可逆性以及响应时间。在较宽的相对湿度范围（20％RH至99.9％RH）下测试了传感器的性能。传感器显示出良好的响应，其信号随周围湿度线性增加。带有GO / 0.3g PVA涂层的锥形光纤传感器具有最高的灵敏度[0.5290RH（％）]。还测量并分析了指定传感器的稳定性，可重复性，可逆性以及响应时间。在较宽的相对湿度范围（20％RH至99.9％RH）下测试了传感器的性能。传感器显示出良好的响应，其信号随周围湿度线性增加。带有GO / 0.3g PVA涂层的锥形光纤传感器具有最高的灵敏度[0.5290RH（％）]。还测量并分析了指定传感器的稳定性，可重复性，可逆性以及响应时间。