All optical photonic crystal ternary inverters based on nonlinear directional couplers

Abstract In this article, a general approach is suggested for creating all-optical photonic crystal ternary inverters. Ternary inverters enable logic operations using three distinct states, offering higher speed and efficiency compared to conventional binary systems. These structures utilize threshold detectors constructed from nonlinear directional couplers, where the threshold value can be tuned by adjusting the radii of the rods within the coupler. To implement ternary inverters, threshold detectors with different threshold levels are integrated with a binary switch. The effectiveness of these designs is evaluated using finite difference time domain and planewave expansion methods. According to simulation results, the worst case propagation delay of the proposed all-optical ternary inverters is approximately 2.5 ps and the smallest contrast ratio of the proposed inverters is about 11.6 dB. All optical photonic crystal ternary negative inverter, ternary positive inverter and ternary standard inverter are proposed in this paper. The binary switch has been designed using threshold logic concept and process variation analysis of the structures is done with Monte-Carlo simulations.