Photonic crystal based all-optical half adder: a brief analysis

Abstract

A photonic crystal (PhC) based optical component paves a path to the upcoming all-optical computer processors. All the components can be realized with the help of PhCs. In particular, optical gates have played a major part in the development of all-optical half adders which has lead to the bloom of optical computing technology. In this paper, a PhC based optical half adder is proposed and a brief analysis is carried out for the different crystal structures and lattice patterns. The efficiency of the device is analyzed by providing proper distinct space in output power between logical '0' and '1' states and it operates well even in the reduced input power level. The error can be minimized while identifying the logical states (logic '0' and logic '1'), by setting a threshold limit for output power. The threshold level is fixed such that if it is greater than 0.7 mu W, it is considered as logic '1', and if it is less than 0.35 mu W, then it will be taken as logic '0'. The device with circular crystals in a hexagonal lattice provides a better contrast ratio of 12.55 dB and 9.29 dB for 'sum' and 'carry' respectively. The miniature size of the proposed device depicts that this device is compatible with photonic integrated circuit (PIC) applications.