An Optical Fiber Sensor Based on FeOOH Nanorod Arrays for Humidity and Temperature Measurement

It remains a major challenge to prepare a temperature or humidity optical fiber sensor with a simple structure, low cost and high sensitivity. In this work, a Mach-Zehnder interferometer with "SMF-MMF-TCF-MMF-SMF" structure is proposed to measure ambient temperature and humidity. The FeOOH nanorod arrays were grown on the surface of TCF to improve the sensitivity of this sensor. This sensor exhibits a high temperature sensitivity of 859.01 pm/°C in the range of 26 °C to 52 °C and a humidity sensitivity of 335.98 pm/% RH in the range of 40% RH to 90% RH. The sensor also exhibits excellent stability and repeatability, with the maximum wavelength deviation caused by temperature change and humidity change being only 0.544 nm and 0.557 nm respectively. This sensor is expected to be applied in some fields such as agriculture, chemical industry, semiconductor manufacturing.