Sensitivity enhancement of cylindrically-symmetric optical fiber refractive index sensors by utilizing graphene

This paper presents a new method of using graphene coating to enhance the sensitivity of the cylindrically-symmetric refractive index (RI) sensors. Previously, it was implicitly considered that graphene coating can only enhance the sensitivity of RI sensors in the polarization differentiating configuration. Many of the conventional RI sensors, including the cylindrical symmetric ones, are incapable of differentiating between the polarization modes. To address this issue, the enhancement in RI sensitivity of a graphene-coated cylindrically-symmetric configuration is studied by modifying the Fresnel coefficients. The theoretical calculations show the possibility of improving the cylindrical symmetric sensors with graphene coating. The proposed coating is quite simple and can be used for the improvement of a major fraction of conventional RI sensors.