International Journal of Research Studies in Electrical and Electronics Engineering(IJRSEEE) Volume 4, Issue 2, 2018, PP 25-32 ISSN 2454-9436 (Online) DOI: http://dx.doi.org/10.20431/2454-9436.0402004 www.arcjournals.org International Journal of Research Studies in Electrical and Electronics Engineering (IJRSEEE) Page | 25 The Effect of Oblique Waveguide on All-Optical Photonic Crystal Logic Gates Yazdan Karimi Pashaki 1* , Rahim Faez 2 1 Sama technical and vocational training college, Islamic Azad university, Lahijan Branch, Siyahkal, Iran. 2 Associate Professor of Department of Electrical, Sharif University of Technology, Iran. 1. INTRODUCTION All-optical NOT logic gate is a basic element in all-optical signal processing and optical telecommunication systems. This logic gate is used to increase processing speed and data transmission [1]. All-optical logic gates based on fiber have difficulty in chip scale integration, and optical logic gates based on waveguide interferometers have a complicated structural arrangement. Moreover, the performance of logic gates with a micro resonator structure and semiconductor optical amplifiers are limited to moment emission noise [2]. Photonic crystals (PC) are a new class of dielectric materials proposed by Yablonovitch and John which can be used in making photonic integration devices with dimensions equal to a wavelength [3]. Presence of photonic crystals (PC) in the design of all-optical logic gates leads to a high potential in compression and reduction of the size of ultra-fast switching devices as well as reduction in power consumption [4].Photonic crystals transmit or reflect light selectively at different wavelengths. There is a period of wavelength which reflects light totally due to scatterings in the crystal lattice and it is called photonic band gap[5]. Forming a defect in the structure of the crystal lattice, light will transmit in the band gap range. A defect is created by removing a row of rods in the crystal lattice structure and is called waveguide [5]. Jiang et al (2010) suggested all-optical photonic crystal NOT logic gate in which two straight waveguides and one photonic resonator located between two waveguides were used to form logic gates. The resonator is placed with a 45 degree angle among waveguides which led to a destructive interference in some frequencies and made passing operations difficult. Amount of passing power was reported %17 in low state and %85 in high state [6]. Nous had et al (2011) proposed a design of two all-optical photonic logic gates; one of them was NOT gate. Photonic straight waveguides were used in a crossover form in this structure. One non-linear rod with a larger radius comparing to other rods was used which lead to increase in the power consumption of the gate. The power transmission in logic gate output was reported %90 in the active mode [7]. Rani Prety et al (2013) suggested another design of all-optical logic gate. In this design, structure of a photonic crystal with a triangular lattice of air holes has been used in the substrate dielectric material and a Y-shape wave guide has been used in the structure to achieve logic gates. One hole with a different radius was made in the center of the waveguide. This structure is totally linear. The proposed rate of clarifying the gate extinction ratio Abstract: All-optical NOT logic gate in the basis of the oblique photonic waveguide structure has been proposed in this paper. The structure of Photonic crystal lattice is triangular and it is formed of dielectric rods in air substrate. The simulation is done using oblique and crossover waveguide structures and a scatter rod in this design. The location of the scatter rod has been selected such a way that the logic gate act as a NOT function in both directions of the structure. The simulated required power consumption becomes200mw for operation of the logic gate. Waveguide bend was used to increase transmission optical power in the proposed scheme and the nonlinear rods were not used which lead to a reduction in the power consumption of the logic gate. Switching time is simulated 0.51ps and extinction ratio of this logic gate becomes9.6 dB. Calculation methods were based on the FDTD and PWE methods. Keywor ds: All-optical logic gate, photonic crystals, Photonic band gap, bend waveguide, Scatter rod *Corresponding Author: Yazdan Karimi Pashaki , Sama technical and vocational training college, Islamic Azad University, Lahijan Branch, Siyahkal, Iran.