All Optical Reversible Multiplexer Design Using Mach-Zehnder Interferometer

With the advancements in semiconductor technology, there has been an increased emphasis in low-power design techniques over the last few decades. Reversible computing has been proposed by several researchers as a possible alternative to address the energy dissipation problem. Several implementation alternatives for reversible logic circuits have also been explored in recent years, like adiabatic logic, nuclear magnetic resonance, optical computing, etc. Recently researchers have proposed implementations of various reversible logic circuits in the all-optical computing domain. Most of these works are based on semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI), which provides desirable features like low power, fast switching and ease of fabrication. In this paper we present an all-optical implementation of a digital multiplexer using MZI switches. Both non-reversible and reversible versions of multiplexer design are proposed, along with analytical evaluation of the design complexities both in terms of delay and resource requirements. The final optical net lists obtained have been compared against traditional reversible synthesis approaches, by using an available synthesis tool and then mapping the reversible gates to MZI switch based implementations. Some techniques for optimizing the final optical net lists have also been proposed. Synthesis results for some reversible benchmark circuits and the standard functions of three variables are also shown.