All-optical Logic Gate Based On High Nonlinear Fiber

All-optical logic gate is a kind of important new optical passive device in future optical networks, which realizes logic operation in optical field, and can avoid O-E-O conversion. All-optical logic gate can be widely applied in addressing, demultiplexing, decision making, regenerating, label switching, coding, parity checking, and so on.All-optical logic gate based on nonlinear effects of fiber possess many unique advantages such as high speed, low power consumption, high efficiency, and so on. With the FWM effect in nonlinear fibers, a novel high speed all-optical AND gate scheme is proposed. On the basis of transmission equation of pulse in nonlinear fiber and FWM principle, an all-optical AND gate theoretical model is developed. A 40 Gbit / s AND gate is realized by numerical simulation, and the affection to the AND output introduced by signal wavelength, pump power, initial pulse width is also studied. The output is influrenced by the walk-off effect introduced by group velocity mismatch. A 20 Gbit / s AND gate based on HNLF-FWM is obtained in experiment, and the variable wavelength range of signal is measured. A cascaded FWM is observed while the input pulses are amplified by high power amplifier. The AND output channels are increased, and the quality of first order output is obviously improved, and the variable wavelength range of signal is broadened.Based on the XPM effect in HNLF, a new XOR gate scheme in nonlinear optical fiber loop mirror is presented. Followed the XPM principle, a theoretical model which is used to describe XOR gate is established. During numerical simulation, a 40 Gbit / s all-optical XOR gate based on NOLM is approached. The XOR output is affected by pump power, signal wavelength and pump pulse width. The XOR output is also influrenced by the walk-off effect introduced by group velocity mismatch.