In this paper, we design an optical filter by using one-dimensional (1d) ternary metallodielectric photonic crystal (PC). We use a dielectric defect layer between ternary asymmetric cells with this structure (ABC) N D M (ABC) N and also increase the number of dielectric defect layers. Then, we plot transmission spectra in terms of wavelength and different angles of incidence in transverse electric (TE) and transverse magnetic (TM) polarizations. We show defect modes and photonic band gap (PBG) on the plane of wavelength and incident angles in both TE and TM polarizations. We also plot transmission in the lossless structure and compared loss and lossless structures. Furthermore, we compare dielectric defect layer with metallic defect layer in both TE and TM polarizations. Moreover, we plot symmetric structure (ABC) N D M (CBA) N in TE and TM waves. The theoretical analysis shows that there is one defect mode which moves to the shorter wavelength by increasing angles of incidence in asymmetric structure. There are also two defect modes in symmetric structure, and by tuning angle of incidence this structure can be used as single channel filter in asymmetric structure and multichannel filter in symmetric structure.

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In this work, we study a multichannel filter by using one-dimensional photonic crystal (1DPC) based on Thue-Morse sequence (TMS). We use a dielectric defect layer between binary sequence cells with a TMS structure. First, we show transmission in terms of wavelength for the structure without defect layers. Then, we plot transmission in terms of wavelength for a different number of defect layer periods (N) in normal incidence. The analysis shows that there are two photonic bang gaps (PBG) in visible and infrared regions and two defect modes in each one for N = 1. Moreover, the number of defect modes is increased by increasing N. So, by tuning them, this structure can be used as a multi-channel filter within an optical wavelength range.