D-shaped silicon core fiber-based surface plasmon-resonance refractive index sensor in 2 μm

In this paper, we propose a D-shaped silicon core fiber sensor based on surface plasmon resonance within the 2 mu m range. Au layer coating on the D-shaped side-face of silicon core fiber acts as a plasmonic active metal. By using the limited element methods, the sensing properties of the proposed sensor are investigated, and an average sensitivity up to 2650 nm/RIU with a resolution of 3.776 x 10(-5) MU is obtained for the analyte of different refractive indices varies from 1.25 to 1.6. In the investigated simulation, we used real parameters of liquid (e.g., CH4 liquid and CHBr3) in our simulations for being closer to reality. In addition, the Au coating layer and analyte are placed on the D-shaped side-face of the proposed fiber sensor; hence, this structure does not need to fill the voids. Thus, it is easy to fabricate and put to use. Also, the wavelength band in 2 mu m is far from the optical communication band, which means the proposed sensor could be connected with a fiber network without any influence and crosstalk. (C) 2020 Optical Society of America