Design and Simulation of Linear All-Optical Comparator Based on Square-Lattice Photonic Crystals

Abstract An optical comparator is an important logic circuit used in digital designs. Photonic crystals are among the platforms for implementing different kinds of gates and logic circuits. Photonic crystals are structures with alternating refractive indices. In digital optics, logical values “0” and “1” are defined based on the level of optical power. In this paper, an optical comparator based on square-lattice photonic crystals is designed and simulated. In the design of this comparator, a small-sized structure is used. The simulation results show that in the proposed comparator, there is a long distance between logical values ​​“0” and “1”. Due to the small size of this comparator and the adequate distance between logical values ​​“0” and “1”, this structure suits photonic integrated circuits with high accuracy.