Investigation of Surface Plasmon Resonance based on Silicon Core Fiber for Large Range of Refractive Index Sensing

In this article, we propose a concept which is the D-shaped silicon core fiber sensor based on surface plasmon resonance within the Mid-IR 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 2.931 μm/RIU is obtained for the analyte of different refractive indices varies from 1.20 to 1.55. 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-μm is far from optical communication band, which means the proposed sensor could be connected with fiber network without any influence and crosstalk.