D-shaped dual-core photonic crystal fiber–based sensor for the detection of fluid analytes

Abstract This proposed work designs a D-shaped dual-core photonic crystal fiber (PCF)–based sensor to sense fluid analytes (FAs) in the range of refractive index (RI) varying from 1.33 to 1.38. In this work, we consider water, propane, ether, ethanol, acetic acid, and propanol with different RIs as FAs, which are key parameters for determining the sensing performance of sensors. In this sensor, two independent waveguides are created because of the presence of a central elliptical hole and two solid cores. This elliptical hole acts as a sensing channel where different FAs are placed. As a result, there is a shift in the peak wavelength due to different RIs of FAs in the transmission curve and the concept of mode coupling theory. The proposed PCF sensor has been numerically studied using the full-vector finite element method. The majority of these features are in the infrared range, and all have been quantitatively explored in a larger wavelength regime of 1.4 µ m–2.4 µ m. The numerical analysis of the sensing parameters for the proposed sensor presents a maximum achieved wavelength sensitivity of 8000 nm/RIU in x -polarized and 7000 nm/RIU in y -polarized. The birefringence is 7.57 × 10 −3 in x -polarized and 7.31 × 10 −3 for y-polarized. Moreover, the transmittance sensitivity was 3726 dB/RIU in x -polarized and 2009 dB/RIU in y -polarized, respectively. The results obtained in this work explain that the structure has high wavelength sensitivity, low confinement loss, and high birefringence.