Nonlinear fiber-optic sagnac interferometer based all-optical logic gate

All-optical logic gate (AOLG) will play important roles in future optical communication systems, optical signal processing and photonic computers. A review on principles and applications of current AOLGs is presented firstly. It is found that current AOLGs are mostly designed as a single processing element. However, it is the ability of connecting of the AOLG that has great influences on the composition of future photonic computers. Then, a novel AOLG based on nonlinear fiber-optic Sagnac interferometer (NFSI) is proposed and demonstrated, and the particular emphasis is given to realizing the ability of connecting. Employing the cross-phase modulation (XPM) in the NFSI, the logic of a NOT gate is realized. In addition, by a wavelength conversion, the light state of both input and output of the NOT gate are identic, which realizes the connection of gates and is with potential significance for designing the photonic computers.