基于聚乙烯醇-铝薄膜的光纤温湿度传感器研究

Optical fiber temperature and humidity sensor based on polyvinyl alcohol-aluminum film

提出一种基于聚乙烯醇（PVA）-Al薄膜的光纤倏逝波耦合温湿度传感器研究,主要包括湿度测量传感器和温度补偿传感器。湿度测量传感器是在单模光纤（SMF）熔融拉锥后的锥区涂覆一层PVA湿敏材料制成,温度补偿传感器是在湿度测量传感器的表面镀覆一层金属Al薄膜制成。实验结果表明：当锥区长为14.04mm、PVA涂覆层的厚为2.2μm时,湿度测量传感器的湿度灵敏度为0.154 1dBm/%,温度对它的影响为0.019 7dBm/℃,可实现湿度50~98%的测量;当Al薄膜厚为168.63nm时,温度补偿传感器的温度灵敏度为0.019 1dBm/℃,通过实验装置能够实现对湿度测量传感器的温度补偿。

An optical evanescent wave coupling temperature and humidity sensor based on polyvinyl alcohol-aluminum film is proposed,including a humidity measurement sensor and a temperature compensa- tion sensor. In the single mode fiber fused taper area, the humidity measurement sensor is fabricated after being coated with the polyvinyl alcohol humidity sensitive material film. The temperature compensation sensor is fabricated by depositing the aluminum film on the humidity measurement sensor surface. In experiment, an amplified spontaneous emission （ASE） light source is used for detecting signals and an opti- cal power meter is designed to measure the output of sensor. The humidity measurement sensor is used to detect humidity only, while the temperature compensation sensor only reflects the variation of environmental temperature. These two sensors work at the same time and the latter is used to compensate the temperature variation in the former. The experimental results show that when the taper length is 14.04 mm and the polyvinyl alcohol coating thickness is 2.2μm,the humidity sensitivity is 0. 154 1 dBm/%, the temperature sensitivity is 0. 019 3 dBm/℃ ,and the humidity measurement range can achieve 50%/6 98 %. When the aluminum film thickness is 168. 63 nm,the temperature compensation sensor sensitivity is 0. 0191 dBm/℃. So the developed device can realize the temperature compensation for humidity meas- urement sensor.