During the past two decades, photonic crystals, in particular photonic bandgap materials have became area of interest of many researchers. In this research, author has discussed the omnidirectional reflection and TE or TM mode filter properties of one-dimensional linear and nonlinear binary and ternary photonic crystal using transfer matrix method. Also, he has studied defect mode one-dimensional photonic crystals having a layer of non-linear material. Using Transfer Matrix method, the properties of such 1D binary photonic crystals have been theoretically studied. Introduction of a single defect in the structure gives narrow transmission peaks in the photonic band gaps of such structures. It is found that the proposed structure can be used as a single channel tunable wavelength division demultiplexer for DWDM systems. The proposed device may also be used as a single channel drop ?lters, monochromator, and it may have many applications in different optical systems.