Nanophotonic interferometer realizing all-optical exclusive or gate on a silicon chip

We present an all optical approach allowing the realization of microscale logic exclusive or (XOR) gate based on special interferometer configuration. The operation device includes two close optical waveguides realized on a silicon chip. A thin metallic layer of a few nanometers that separates the two waveguides causes a relative phase shift of π between them. The structure performs interference of the two input beams while demonstrating XOR logic gate operation at the amplitude of the resulted output. The logic operation is realized after small propagation distance of <1.8μm.