Simulation of Nanoscale Multifunctional Interferometric Logic Gates Based on Coupled Metal Gap Waveguides

A novel design of ultrasmall multifunctional Boolean logic gates is proposed in this letter. This interferometric logic device is based on the coupled metal waveguides. This structure is a theoretical analysis, and logic performances are proved by using the finite-difference time-domain method. The single device can perform individually four different kinds of basic functions: and, or, xor, and not operations. The device with an extremely small feature size is an attractive candidate for high density nano-photonic integrated circuits.