Multi-channel filter based on defects coupled in one-dimensional photonic crystal

The transmission spectrum of one-dimensional photonic crystal which has multi-defect in equidistant distribution is investigated using the optical transmission matrix method. Quarter-wave stack photonic crystals with five defects are calculated. The results show that, when the distance between the defects is increased for a period, the transmission peaks tend to close to the central wavelength, the first transmission peak shifts to the position where the second peak exist, and the fifth transmission peak shifts to the position where the fourth one exist. The structure is fabricated by the coating process, and then transmission peaks are measured by a MP-5000 spectrophotometer. Experimental results are consistent with the theoretical calculation. The corresponding relationship between the distance of the defects and the position of transmission peaks is directive and meaningful for designing the multi-channel filter.