热应力和残余气压对光纤法布里-珀罗压力传感器温度性能的影响

Effect of Thermal Stress and Residual Gas Pressure on the Thermal Response of Optical Fiber Fabry-Perot Pressure Sensor

针对光纤法布里-珀罗（F-P）压力传感器,建立了考虑热应力和残余气压的F-P腔长变化模型,进行了热应力和残余气压对传感器温度性能影响的理论分析。分析表明,热应力和残余气压的引入使F-P腔长改变量与温度的线性关系发生了变化,在外界施加100 k Pa压力,当腔内残余气压小于0.87 k Pa时,热应力起主要影响作用;当腔内残余气压大于0.87 k Pa时,残余气压起主要影响作用。制作了三种不同残余气压的光纤F-P压力传感器,在-20℃~70℃温度范围进行了实验研究,结果显示测量的腔长及其温度灵敏度随温度变化关系与理论分析基本一致。

A new model for optical fiber Fabry-Perot（F-P） pressure sensor with thermal stress and residual gas pressure is presented, then their impacts on thermal response of the F-P sensor are analyzed. It shows that the linear relationship between the change of cavity length and temperature has changed when thermal stress and residual gas pressure are considered. In the condition that the applying outer pressure is 100 kPa, the thermal stress plays a major influence on the sensor when the initial residual gas pressure is less than 0.87 kPa,otherwise the residual gas pressure plays the major influence on the sensor. Three kinds of optical fiber F-P sensors with different residual gas pressures are produced, then the experimental system in the temperature range from-20 ℃ to 70 ℃ is built. The result shows that the cavity length and the thermal sensitivity varying with the temperature from the experimental data agrees well with the theoretical analysis.