Chemical sensing through photonic crystal fiber: sulfuric acid detection

A photonic crystal fiber (PCF) for sensing of sulfuric acid is designed and analyzed using Comsol Multiphysics. To analyze the sensor performance, 0%, 10%, 20%, 30%, 40% H2SO4 solution is placed into the fiber separately and then relative sensitivity, confinement loss, birefringence, effective area etc. are investigated for each solution over wavelength ranging from 0.8 to 1.8 mu m. The sensor structure affords moderately high relative sensitivity and around 63.4% sensitivity is achieved for the highest concentration of H2SO4 at the wavelength 1.5 mu m in x polarization direction. This PCF model also shows zero confinement loss for all solutions of H2SO4 over wavelength ranging from 1 to 1.35 mu m and later on approximately 1.422 x 10(-17) dB/km confinement loss is found for the highest concentration of H2SO4 at 1.5 mu m wavelength. Besides, higher birefringence is attained when the concentration of sulfuric acid is lower and it is achieved 7.5 x 10(-4) at 1.5 mu m wavelength. Moreover, higher sensing area is achieved at high concentration of sulfuric acid.