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In the development of the technology of all-optical integrated circuits, the logic gates play considerable role in the progress of optical components. As one of the main building-blocks of an optical system, a high-performance 2*4 all-optical decoder is proposed and studied based on nonlinear effects in a photonic crystal ring resonator. The proposed structure consists of 1*2 decoders which are combined to operate as a unique 2*4 decoder and this will let us to extend the design to decoders with increased inputs. An optical bias is used to interact with input signals, and each output port is enabled for a given code in the input code. Numerical simulation methods such as plane wave expansion and finite difference time domain are performed to study the operation of proposed structure. Results of simulations show that for an on-state output, the highest achievable power is about 87% and the lowest value is 40%. For the case of 40%, the on/off ratio of outputs is at least 2.22 which ensures the acceptable resolution needed for detection of on-state. Maximum cross-talk about −10 dB and insertion loss about −8.8 dB is obtained for proposed decoder. [ABSTRACT FROM AUTHOR]

In this paper a high efficiency optical power splitter based on two-dimensional photonic crystals is proposed. The photonic crystal cavity is assumed to be constructed by TiO2 nanorods with refractive index n = 2.609. To do so, first we implement some techniques to design a 1*2 optical power splitter, which include Y-shape waveguides and various types of defects such as point and line defects. The results of numerical simulations show that at the wavelength range of DWDM systems, the proposed 1*2 power splitter has the maximum efficiency of 99.616 %. A similar method is employed to design a 1*4 splitter with high performance operation at the same wavelength range which relates to the efficiency of 99.21% that is the highest amount between these type of power splitters. The final size of these high efficiency power splitters is 130μm2 (10μm*13μm) which make them suitable for integrated optical circuits. [ABSTRACT FROM AUTHOR]