Design and Performance Analysis of Octagonal Cladding Photonic Crystal Fiber for Chemical Sensing

In this study, an octagonal-shaped liquid-infiltrated photonic crystal fiber (PCF) has been proposed for liquid sensing such as water and ethanol. The finite element method (FEM) based COMSOL Multiphysics software has been used for the analysis of the performance of the sensor. The PCF sensor is designed in such a way that it contains a hollow central circular core surrounded by five layers of octagonal cladding. The simulation was performed to obtain the best results in terms of relative sensitivity, confinement loss, power fraction, and effective mode index through numerical analysis. The relative sensitivities of water and ethanol were obtained relatively high at a lower operating optical signal, which were 95.344 % and 96.9 %, respectively. Also, the low confinement loss for these analytes was reported. The confinement loss for the studied PCF, were calculated to be 2.58 × 10^-9 dB/m and 4.50 × 10^-10 dB/m for water and ethanol, respectively. The proposed PCF can be fabricated easily for industrial use.