Optical fiber coated with Nafion® thin film for humidity sensing

It has developed a simple fiber optic sensor that is used to detection and measure concentration of water vapour in the air. The operating principle of the sensor is discussed in this work, and it was noticed that the wavelength positions of the reflectance peaks change with the concentration of H2O molecules. The sensor has been successfully used to monitor relative humidity of the air. The sensor utilizes a layered Fabry-Perot interferometric sensing structure. This structure was fabricated on the end of standard multi-mode fiber optic and includes Nafion (R) sensing film. The fiber optic hygrometer was tested for measurement of relative humidity in the range of 10-80% in air. SHT75 sensor (Sensirion Corp.) was used as reference sensor for control humidity level and temperature of gas mixture.