Improved Sensitivity of the Refractive Index Sensor Based on a Photonic Crystal Waveguide

In this paper, we used the finite-difference time domain method to analyze the wavelength spectrum as detected at the end of two-dimensional photonic crystal waveguide that contains circle- and ring-shaped silicon rods distributed in an air wafer. A shift of 0.0758 m in the wavelength position of the upper band edge, corresponding to a sensitivity of 758 nm/RIU, was observed. A local defect has been introduced, which produces a very high shift in the cutoff wavelength corresponding to a higher sensitivity of 1490 nm/RIU.