Compensation Of Thermal Effect Of Optical Fiber F-P Sensors

Aerodynamic measure balance,which is made by metal material and based on sensors to obtain some information of strain,is one category of highly precious sensing devices.This device not only has to work in complex environment with high temperature,high pressure and strong electromagnetic interference,but also demands high-accurate result of measurement.Currently,the optical fiber sensing technology has being developed for several decades and is becoming more and more mature in domestic.Optical fiber Fabry-Perot sensors,due to these advantages of high sensitivity,small size and so on,have received much attention and been playing an increasingly important role in measurements of aerodynamic balance in extremely complex environment.However,the optical fiber Fabry-Perot sensor would be affected by the thermal expansion of metal substrate,temperature drift and other interference factors.Thus the result of aerodynamic balance measurement may not be that accurate.How to eliminate the influence of the thermal effect of optical fiber Fabry-Perot sensor in the process of practical measurements of aerodynamic balance becomes an urgent bottleneck problem during the aerodynamics research.This thesis focuses on the optical fiber Fabry-Perot sensor,which is the research object,and is the type of sensor installed on the metal cantilever beam,which is made by the same metal material as the aerodynamic balance does,for the sensing measurement.In this thesis,the working principle of optical fiber Fabry-Perot sensors is described.In order to solve the problem of the cross-sensitivity of temperature and stress in the strain measurement of metal substrate,the thesis studies on the cross-sensitivity issue deeply.A variety of methods to eliminate the thermal effect are explored and validated.And this thesis illustrates a various methods of making fiber Fabry-Perot sensors and the relevant process.(1)this paper verified three different kinds of temperature compensation methods about Fabry-Perot sensors,and puts forward a new way of double-parallel measurement used fiber Fabry-Perot sensors for temperature compensation.The novel structure contains a reference arm and a measuring arm.And the two optical fiber Fabry-Perot sensors were installed the sheet-like structure.This method is simple and practical.The field test results show that the method has a good effect of temperature compensation and meets the requirements of engineering application.(2)this paper improved the commonly used methods of making optical fiber Fabry-Perot sensors,took advantage of the ANSYS software to simulate these thermal compensation schemes and put forward two new methods of design and fabrication of Fabry-Perot sensors with automatic temperature compensation function.One is the open-type fiber-metal of optical fiber Fabry-Perot sensors;the other is the closing type of optical fiber Fabry-Perot sensors with the metal coating treatment on both sides of the cavity.The thermal effect of optical fiber Fabry-Perot sensors has been curbed,to some degree,and these two categories of Fabry-Perot sensors have compensation effects.