D shaped PCF based Plasmonic Refractive Index Sensor with Ultra Low Loss

This paper presents a novel biosensor design employing the Finite Element Method (FEM) with Perfectly Matched Layer (PML) boundary conditions to enhance the sensitivity and accuracy of external sensing mechanisms. The biosensor features a D-shaped fiber with the elliptical air holes, optimized for refractive index (RI) detection from 1.36 to 1.44. Two interrogation methods—wavelength as well as amplitude— were applied for the performance measurement of sensor. The wavelength sensitivity (WS) achieved was 33,000 nm/RIU, and the amplitude sensitivity (AS) was determined to be 726 RIU<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup>. Additionally, the wavelength resolution (WR) was calculated as 3.03 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−06</sup> nm/RIU, indicating the biosensor’s high precision. The Figure of Merit (FOM) of 825 and a coefficient of linearity (R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>) of 0.9993 further validate the efficiency and reliability of the proposed design. These results demonstrate the biosensor’s potential for high-performance applications in biochemical and environmental monitoring, offering a significant advancement in the field of optical sensing technologies.