Parallel Adder with Optical Fourier Transfer

Abstract

Optical information processing is expected to realize high performance and a large capacity of computing for its natural parallelism, non-interfering transmittance and wide bandwidth. However, carries make the optical computation difficult with its natural parallel processing of each digit. In this paper, the optical adder in the modified signed-digit (MSD) number system is discussed. The MSD system does not cause carries, but is difficult to deal with negative numbers. We propose a method with not only optical intensity and optical phase information but also polarization. We prototype the logic elements for the MSD adder using the optical Fourier transform, to show that this would realize a MSD adder and function as a subtraction. We further discuss on the parallelization by multiple optical logic units and multiple frequencies.