Study of a Surface Plasmon Resonance Optical Fiber Sensor Based on Periodically Grating and Graphene

In this paper an optical fiber sensor based on plasmonic resonance of graphene and periodically grating is designed and investigated. The proposed sensor consists of an optical fiber core coated by a copper film, a periodically grating layer and a mono-layer graphene, respectively. Originality of the design comes from insertion of periodically grating layer accompanied by a mono-layer graphene sheet. The structure is optimized and parameters for best performance are introduced. It is shown that applying the periodically grating results in performance enhancement of the sensor. Parametric study is performed and optimized values of copper and grating thicknesses are calculated. With varying refractive index of sensing layer in the range 1.3-1.36, the proposed sensor is investigated and compared with designs based on plasmonic resonances of copper coated by monolayer graphene. It is shown that with applying periodically grating a maximum sensitivity improvement of 5.1 m/RIU is achieved, while Quality Factor and Detection Accuracy are maintained in their reasonable ranges.