Photonic Crystal Waveguide Biochemical Sensor for the Approximation of Chemical Components Concentrations

The rapid progress in chemical and biochemical applications with optical interfaces has motivated an ever-increasing demand for highly sensitive, accurate, and disposable photonic components. We propose a design of biochemical sensor to identify the chemical components acid concentrations with a greater accuracy using photonic crystal waveguide (PCW). It consists of circular air holes of radius 0.44 a (a being the lattice constant), arranged in a hexagonal structure on silicon on insulator (SOI). Due to change in refractive index of the sample, resonance wavelength shifts towards higher wavelengths (red shift) with a higher coefficient of determination. The proposed design allows desired input wavelength of 1550 nm to be guided in the waveguide for an effective identification of chemical component concentration. Resolution and limit of detection are calculated as 1.2 nm and 4 × 10−2 RIU for sulfuric acid (H2SO4) solution and 0.2 nm and 2 × 10−2 RIU for hydrogen peroxide (H2O2) solution. Improved sensitivities with increased standard deviations are achieved after structural optimization.