Degeneracy and splitting of defect modes in one-dimensional symmetric photonic crystal

In this study, we focus on the analysis of one-dimensional photonic crystal with symmetric double defect. Using the transfer matrix method (TMM), the properties of defect modes including degeneracy and splitting, can be analyzed in detail. It is found that such properties are mainly depending on symmetry and spatial interval of defects. The results show that the degeneracy of defect modes occurs in two defects separate to each other. And defect modes split when two defects close to each other. The results have potential applications in photonic integration and fiber optic sensor.