Multi channel narrowband DWDM optical filters based on generalized aperiodic Thue-Morse structures

An In this paper a multi channel narrow band DWDM filter based on aperiodic Thue-Morse (TM) multilayer structure is proposed. We study the transmission spectra of light propagation through these structures. Our numerical simulation shows an ultra high efficiency for this filter so that the total transmission of filter output channels up to 100% and the range of output wavelength is 1550 nm which is suitable for DWDM communication systems. By studying the effects of parameters of aperiodic Thue-Morse structure, we realized that with varying the parameters such as number of layers, the distance between layers, the refractive index of layers, and so etc., we can accomplish a suitable DWDM filter and the structure properties are changeable with them. For example, by increasing the distance between each layer, the bandwidth of output channels less than 1nm is obtained. The main advantage of Thue-Morse structure is the selectable layer numbers of it, that in our designed structure, we generalized the base structure and choose TM(3,2) that means m=3 and n=2 in B^mAⁿ.