Frequency encoded data based optical full adder using reversible Toffoli gates

Abstract

In WDM communication based networks the processors have to deal with large number of data. It is seen that the data loss becomes significant when the conventional logic gates have been used as the building block of the processors. The reversible logic gates already have established its utility due to its low power consumption and less hardware complexity. In case of reversible logic gate, inputs are directly mapped to outputs after performing some logic functions. As the inputs of the reversible gate can be uniquely recovered from the outputs, power loss is ideally zero. Toffoli gate, invented by Tommaso Toffoli is one of the most common universal reversible logic gates. It is a three-input-three-output reversible logic gate. In this article, authors have proposed a new technique of designing optical Toffoli gate, and subsequently propose a method of developing an optical full adder with the help of Toffoli gates. For this purpose the authors have deployed the polarization switching characteristic of semiconductor optical amplifier (SOA). The authors have exploited frequency encoded data due to the inherent identity. The proposed optical frequency encoded full adder will be a key component of an optical reversible Arithmetic Logic Unit (ALU), or any other reversible optical computing. Simulation results of the Toffoli gate based on theoretical model PSW show the feasibility of the of the proposed scheme.