Tapered Optical Fiber Humidity Sensor Research Based On Humidity Sensitive Film

As a new type of humidity sensors, optical fiber humidity sensor has a compactstructure, easy fabrication, high sensitivity, fast response speed, wide measuring range,small wet hysteresis, good repeatability, and many other advantages. Based on wavelengthdetection and light Intensity modulation type optical fiber sensing principle and researchresults of humidity sensor, this paper proposes a tapered optical fiber humidity sensorresearch based on polyvinyl alcohol-aluminum film, the main contents include:First, this paper introduces the classification of the optical fiber humidity sensor foroptical fiber humidity sensor at home and abroad research status; theoretical analysis ofthe tapered optical fiber transmission characteristics, as well as the relevant principles offiber optic evanescent wave, lay the foundation for the study of optical fiber humiditysensor.Next, using the chemical etching, CO2laser pull cone method and fused taper methodto study the preparation of tapered fiber, and observe the parameters of the conicalstructure by electron microscopy imaging system; Theoretical analysis of the fusedtapered single mode fiber sensing characteristics, and glycerin refractive index sensingexperiments.Again, research the PVA humidity sensitive material preparation and the refractiveindex sensing experiment; research the dip coating method and the vertical dip coatingprepared humidity measurement sensor; research the temperature compensation sensor isfabricated by depositing the aluminum film on the humidity measurement sensor surface.Finally, experimental study on the humidity measurement sensor of humiditycharacteristics, wet characteristics, repeatability, temperature characteristics; experimentalstudy on the temperature compensation sensor of humidity characteristics, temperaturecharacteristics, reversibility, and analyze the sensor temperature compensation function.