Optical Realizations of Reversible Logic.

Md. Mazder Rahman

W. David Pan, M. Nalasani

This work presents the logical reversibility. The inputs and outputs of reversible logic gates can be uniquely retrievable from each other. The reversible logic operations can't erase information and dissipate zero heat. The circuit actually operates in a backward operation, allows reproducing the inputs from the outputs and consumes zero power. As the basic elements of any logic circuit, logic gates are used to realize Boolean functions. By combining reversible logic gates, reversible circuits can perform complex logical and arithmetic operations. A one-to-one mapping between inputs and outputs is realized. The logical operations run backwards by cascading a reversible logic gate with its dual (inverse). Reversible circuits are also called lossless circuits, as there is neither energy loss nor information loss. These circuits are very attractive for applications where extremely low power consumption, or heat dissipation, is desirable in areas ranging from communications, low power VLSI (very large-scale integration) technology, optical computing to nanotechnology. Reversible logic found to be very useful in quantum computing where the quantum evolution is inherently reversible.

Tanay Chattopadhyay

Abstract A reversible logic gate differs from the conversational logic gate in many ways, such as equal number of input–output, its reverse operation and bijective input/output mapping. In this paper, a new class of 4 × 4 conservative-reversible logic gate named the equalizer SWAP gate (ESG) has been proposed. This gate is self-invertible and performs SWAP operation when two of its control inputs are logic either 0 or 1. The all-optical design of the ESG using a ‘semiconductor optical amplifier (SOA) assisted Sagnac interferometer’ with a counter-propagating signal passing through the SOA has been shown with a mathematical model in this paper. Quantum realization of the ESG has been carried out to construct its unitary matrix. Also, the matrix has been established through numerical simulation. Some complex reversible logic circuits, viz. n -bit XOR/XNOR, full-adder circuit, n -bit binary-to-gray and gray-to-binary conversion, using the ESG unit have also been shown. Simulated outputs, logical complexity, quantum realization, optical cost and delay of the proposed circuit have been analyzed, and are compared with other reversible logic gates.

Ralph C. Merkle

Pradeep Singla, Naveen Kr. Malik

In the recent era, Reversible computing is a growing field having applications in nanotechnology, optical information processing, quantum networks etc.In this paper, the authors show the design of a cost effective reversible programmable logic array using VHDL.It is simulated on Xilinx ISE 8.2i and results are shown.The proposed reversible Programming logic array called RPLA is designed by MUX gate & Feynman gate for 3-inputs, which is able to perform any reversible 3-input logic function or Boolean function.Furthermore the quantized analysis with comparative finding is shown for the realized RPLA against the existing one.The result shows improvement in the quantum cost and total logical calculation in proposed RPLA.

Anas N. Al‐Rabadi