| With the development of information technology and industrial application,optical fiber sensing technology is being used more and more.EFPI,as one of the optical fiber sensors,which has been mature applied in the building and monitoring because of its small size and free of electromagnetic interference,etc.,and its popular in the field of optical fiber sensing.In this paper,the common structures of EFPI fiber sensor and the sensing mechanism of Fabry-Perot cavity are introduced firstly,and briefly analyzed EFPI how does transmit pressure,transmit temperature and demodulation ways in common.Secondly,using COMSOL Multiphysics for structural modeling and lateral load pressure simulation about EFPI.The simulation results show that the middle part of the sensor bears the maximum force under the lateral load pressure.The effects of material parameters such as fiber core elastic modulus,sensor length,F-P cavity length and capillary elastic modulus on the sensor effect are simulation experimented,and the conclusion that the sensor effect is better when the fiber core elastic modulus is smaller,the sensor length is shorter,the cavity length is shorter,and the glass tube elastic modulus is smaller.The fusion process of EFPI fiber sensor is introduced in detail.The fusion process is carried out by epoxy resin adhesive.Then,proposed a kind of Lissajous-Figure and the standard form of elliptic curve fitting,using Empirical Mode Decomposition(EMD)to the basic demodulation algorithm,this algorithm demodulation cavity length relative error is 1.55%,the accuracy is higher.Finally,the proposed demodulation method is applied to the transverse load experiment,and the results show that the wavelength,light intensity and cavity length are linearly related to the load as the pressure increases.The EFPI sensor with the F-P air lacuna of 206 um and 298 um was used for wavelength and light intensity analysis,and the conclusion that the short cavity length sensing effect is better,which was consistent with the simulation results.The theoretical calculation and demodulation value of the cavity length variation are compared,and the relative error is 6.9%,which shows the demodulation way is precise. |
