Investigations on the Highly Sensitive Metal-Coated Broad Range D-Shaped Optical Fiber Refractive Index Sensor

Abstract

In this paper, we present a detailed study on surface plasmon resonance (SPR)-based D-shaped single-mode optical fiber sensor for the range of refractive index (RI) 1.33–1.42 sensing using the finite element method (FEM). Gold (Au), silver (Ag), and copper (Cu) metal layers have used separately to investigate the performance of proposed sensor employed with SPR conditions. Average and maximum sensitivity of the sensor increases with the thicknesses of the metal layer. We observe the higher sensitivity for the Au layer in comparison to Ag and Cu layers. Sensor with Au layer with 50 nm thickness shows the average sensitivity of 5855 nm/RIU with maximum sensitivity of 15,200 nm/RIU and resolution 1.780 × 10−5 RIU. The figure of merit (FOM) has also investigated for such sensor. The sensing performance of the sensor sequentially decreases with Ag and Cu layers. The proposed optical fiber sensors with high sensing performance can be utilized as RI sensors for different chemical and biological sensing. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.