Design and characterization of rectangular slotted porous core photonic crystal fiber for sensing CO2 gas

In this article, we propose a rectangular slotted porous core photonic crystal fiber (RSPC-PCF) for sensing the CO2 gas. The RSPC-PCF is made of purely silica material with rectangular air holes in core and circular air holes in cladding. The COMSOL Multi-physics software with version 4.5.150 is used as a design and simulation tools. The effects of tuning the geometrical parameters have been numerically analyzed by using full-vector finite element method (FEM). The numerical results show the maximum relative sensitivity of 24% and minimum confinement loss of 0.0012 dB/m at 4 μm the absorption wavelength of CO2 gas. In addition, numerical aperture (NA) is also explored to check the light acceptance of the sensor. Since our proposed design is very simple having better sensitivity, it will be a suitable candidate for sensing the CO2 gas in the earth's atmosphere effectively.