Numerical analysis of All-Optical universal NAND and NOR photonic crystal logic gates by creating holes in silicon material

Abstract

All-optical NAND and NOR logical gates based on two-dimensional photonic crystals have been designed and analyzed in this research. A hole in the silicon substrate was created to design the desired gates, and the light emission analysis was performed using the FDTD numerical method. Most of the circuits that have been designed so far based on photonic crystals have included dielectric rods in the airfield. This research uses a hole in the silicon substrate, which is more suitable for fabrication. The proposed structure is created symmetrically using a small photonic crystal. The simulation results show that this small structure can be used as two NAND and NOR gates, which have a suitable power difference in the upper and lower logic states. Therefore, the proposed structure is suitable for precise logic circuits and high transmission speed. Due to the simplicity of structure and small size, the output stable time for NAND and NOR gates are 0.9 ps and 0.67 ps, respectively, indicating the gates’ low delay time. Also, the value of the contrast ratio for NAND and NOR gates is 7.26 dB and 6.35 dB, respectively, which indicates the appropriate power difference in the upper and lower logic states.