Design of an All-Optical AND Logic Gate based on Photonic Crystal with Small Dimensions Suitable for Integrated Optical Circuits

In this paper, using a two-dimensional photonic crystal, a compact and simple structure is introduced for an all-optical AND logic gate. The designed structure consists of three photonic crystal waveguides connected by a nano resonator. The nano resonator is formed by increasing the radius of the dielectric rod. Analysis and investigations have been done using the finite-difference time-domain and plane wave expansion methods. The plane wave expansion method is used to obtain photonic band gap and finite-difference time-domain method is used to study the electromagnetic field behavior in photonic crystal structure. The advantages of this design are small dimension, the high possibility of realization, and high output power in logical state of 1. The delay time of this gate is 0.32 ps. The minimum ratio of the received optical power to the input power in logical state 1, is 1.968 and the maximum ratio of the optical power to the input power in logic zero mode is 0.492. So, the contrast ratio for the designed logic gate is 6 dB. The high output power allow the logic gate to enable to be integrated the next level logic gates into the optical integrated circuits. Considering the features mentioned, this logic gate can be used in optical integrated circuits.