Research On Fiber Optic Temperature And Humidity Sensor Based On Fine Cone Mach-Zehnder Interference

This paper starts from the industrial plants and agricultural vegetable greenhouses that need to control the temperature and humidity environment parameters.Because the optical fiber sensor has the outstanding advantages of small size,simple structure,high sensitivity,and strong electromagnetic interference resistance,it is widely used in a variety of environmental temperature and humidity Measurement.The article mainly studies two kinds of optical fiber temperature and humidity sensors based on fine cone MZI.1.This paper proposes a method for making fine cone structures using a precision micro-machining platform for special optical devices,and conducts a characteristic study of the MZI cone structure;and then proposes a cone diameter and a fine cone length and sensitivity for the fine cone structure The relationship between:the smaller the diameter of the thin cone,the longer the length,the higher the sensitivity.2.This thesis designed a fiber optic sensor based on the MZI with double fine cone structure,and the experiments have verified that the maximum sensitivity is 208.6pm/? and 50%RH?70 in the temperature range of 20??95? The sensitivity of the sensor in the humidity change range of%RH and 70%RH?80%RH is-0.019dB/%RH and-0.055dB/%RH,respectively,indicating that the double fine cone structure optical fiber sensor has a good linear relationship between temperature and humidity The experimental results are consistent with the theoretical derivation.3.This thesis designs an optical fiber sensor based on the MZI based on the cone-cone structure,and conducts temperature and humidity experiments on the sensor.Experiments verified that the temperature sensitivity of the interference peak wavelength demodulation in the range of 1550nm?1558nm is 40.3pm?,and the temperature sensitivity of the interference valley intensity demodulation in the range of 1558nm?1565nm is-0.0612dB/?;the humidity sensitivity of the sensor is0.0153dB/%RH,indicating that the double fine cone structure optical fiber sensor has a good linear relationship between temperature and humidity,and the experimental results are consistent with the theoretical derivation.4.The two sensors proposed in the paper have been experimentally verified to show that temperature and humidity can be measured by intensity change or wavelength demodulation,and have the advantages of compact size,simple structure,low cost,and high sensitivity.They can be used in industrial production and agriculture.Environmental temperature and humidity monitoring in the field.