%0 Journal Article
%T Important Effect of Defect Parameters on the Characteristics of Thue-Morse Photonic Crystal Filters
%A Hamed Alipour-Banaei
%A Farhad Mehdizadeh
%A Mahdi Hassangholizadeh-Kashtiban
%J Advances in OptoElectronics
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/856148
%X Design and characterization of optical filters based on photonic crystal Thue-Morse structures are theoretically examined using transfer matrix method. It is shown that by introducing defect layer in the original structure of the proposed filter, main characteristics of it are changed. The main advantage of this defect in Thue-Morse structure is its capability for DWDM communication applications. In other words, achievement of DWDM filter through the Thue-Morse photonic crystal structure is much easier. The desired wavelengths can be achieved by changing the defect parameter. High efficiency of the proposed filter is one of its benefits. The transmission efficiency of this structure is about 96% and the quality factor is more than 77000. 1. Introduction The advent of Wavelength Division Multiplexing (WDM) and Dense Wavelength Division Multiplexing (DWDM) technologies is an important step toward realizing all optical communication network [1, 2]. By use of these technologies one can optimize the capacity of optical fiber by launching multiple (4, 8, or more) optical channels at different wavelengths into one single fiber. Optical filters are crucial devises for WDM and DWDM systems [3, 4]. Besides omitting the noise from channel information, optical filters are used for separating the undesired WDM and DWDM channels from desired channels. Other crucial applications of filters are in demultiplexing multiple channels in WDM and DWDM systems [5¨C7]. Since the discovery of photonic crystal in 1987 [8, 9], designing compact and highly selective optical filters has become possible. Thanks to these artificial periodic structures we can control the flow of light in ultrasmall scales [10]. Due to the simplicity of design and fabrication, 1D PhC based filters are the mass popular devices realized based on PhC. The key feature of PhCs is a wavelength region in which no optical wave is allowed to propagate inside the crystal; this feature is called Photonic Band Gap (PBG) [11]. We can use the PBG property of 1D PhC to design optical reflector [12] and band reject filters [13]. Adding a defect layer to a 1D PhC creates a narrow band transmission filter [14]. Also if we replace the defect layer by a photonic quantum well [15] we will have a multichannel filter. By replacing dielectric layers by super conducting PhC we can realize a multichannel filter without using defect layer or quantum well [16]. In 1984 Shechtman [17] proposed a new class of crystals called quasi-periodic and aperiodic crystals. Fibonacci, Thue-Morse, and Rodin-Shapiro structures are some example
%U http://www.hindawi.com/journals/aoe/2013/856148/