Abstract
With regard to the design of optical fiber Fabry-Perot cavity using graphene as sensitive diaphragm,the deflection change under uniformly distributed loads in graphene film was analyzed by finite element method based on the large deflection elastic theory of circular film. The pressure-sensing mathematical model of optical fiber Fabry-Perot cavity with graphene diaphragm was established based on the working principle of Fabry-Perot interferometer. The effects of graphene film layer and incident light angle on the film reflectivity were obtained according to the refractive index characteristics of the film. Then the interference spectra change,caused by both the cavity length losses and the film deflection deformations under the pressure loads,were analyzed. The simulation results show that adding the film layer can increase the film reflectivity and further improve the optical interference performance; however,a decreasing effect on the deflection deformation is caused by the film layer with the increase of pressure load. Thus,an 8 layer graphene film can achieve a reflectivity of 0. 715% and an approximate theoretical sensitivity of 10 nm / k Pa for a 40 μm Fabry-Perot cavity length with a membrane diameter of 25 μm. It provides a theoretical basis for the design and fabrication of high-sensitivity fiber-tip pressure sensor with multiple-layer graphene diaphragm.
Published Version
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