Research On Dual Sensing Of Optical Fiber Gas Pressure And Temperature Based On PDMS

Due to the advantages of high sensitivity,flexible structure,simple preparation,low cost and anti-electromagnetic interference,temperature and gas pressure sensors based on Fabry-Perot(F-P)interference are favored by researchers,and now they have been widely used in various practical fields.With the maturity of the preparation technology of optical fiber dual-parameter or multi-parameter measurement sensors,the gas pressure-temperature dual parameter measurement sensor can be used for the simultaneous measurement of gas pressure and temperature,which can meet the sensing needs of many practical applications and attract more researchers' attention.In this paper,polydimethylsiloxane(PDMS)is used to prepare optical fiber F-P dual parameter measuring sensor of temperature and gas pressure.The details are as follows:A high-sensitivity optical fiber F-P temperature sensor based on PDMS is proposed and prepared.The air cavity fiber F-P temperature sensor is fabricated by using a single mode fiber embedded inside the hollow capillary tube and then filling with PDMS in the capillary tube.We theoretically analyze the working principle of the sensor,and prepare four sensor samples with different structure lengths,and test their temperature response characteristics.The highest temperature sensitivity of-23.22 nm/? was obtained.Next,a comparative analysis of sensor samples with different structural lengths was conducted,and it was found that the length of the air cavity and the thickness of the PDMS both affected the sensitivity of the sensor.Under the same conditions,it was concluded that the greater the thickness of the PDMS,the higher the temperature sensitivity of the sensor.Finally,the reversibility experiment of heating-cooling is carried out on the sensor,which proves the good reversibility and practicality of the sensor.An optical fiber gas pressure-temperature dual-parameter measurement sensor based on PDMS is proposed and prepared.A section of hollow capillary is welded behind the single-mode optical fiber,and PDMS is filled in the capillary in sections to prepare the sensor structure.By comparing and analyzing the structure length and sensitivity of the three sensor samples,it is concluded that under the same conditions,the longer the PDMS in the front section,the higher the temperature sensitivity of the sensor,and the thinner the PDMS diaphragm in the back end,the higher the gas pressure sensitivity of the sensor.The temperature and gas pressure sensitivity of the sensor obtained by the experiment are 2.62 nm/? and 20.63 nm/MPa,respectively.And the maximum errors between the measured value and the set value of the temperature and gas pressure obtained by the experiment are 0.23? and 0.09 MPa,respectively.Finally,an experimental system was built,and the sensitivity coefficient matrix of dual parameter measurement was used to realize the simultaneous sensing of dual parameters of gas pressure and temperature,and the mean square error of the simultaneous measurement of dual parameters was 2.165 KPa and 0.052?,respectively.The reversibility experiments of the sensor's heating-cooling and boost-bucking processes within a certain range are carried out to verify the reversibility and practicability of the sensor.