Investigation of Defect Modes in Symmetric 1-D Ternary Photonic Crystal

In this paper, we investigate a 1-D ternary photonic crystal (1-DTPC), with symmetric geometry. The defect modes for both TE and TM polarization are investigated by variation of wavelength. In this case, there are two resonant peaks within the photonic bandgap (PBG) which corresponds to the so-called defect mode. In the TE polarization, by increasing the incident angles the defect modes are shifted toward the shorter wavelength, and in the TM polarization shifted toward the larger wavelength. The height of defect modes is not related to the incident angles. By increasing the number of unit cells, the width of the defect modes is decreased and this increase doesn’t influence the position of defect mode. Furthermore, by increasing the refractive index of the defect layer, the defect modes are shifted toward the center of the bandgap for TE and TM polarizations. The defect mode with a shorter wavelength is shifted faster than the defect mode with a larger wavelength. By increasing the thickness of the defect layer, the defect modes are shifted toward the larger wavelength.