PAM–ASK optical logic gates in an optical fiber Sagnac interferometer

In this work we performed a numerical study of optical logic gates based on a Sagnac interferometer, operating with short optical pulses (10ps) in a PAM–ASK modulation scheme with binary amplitude modulation scheme. We examined the performance of a nonlinear Sagnac interferometer implementing two-input logical functions. We evaluated the effect resulting from an increment in the PAM coding parameter offset (ε), considering the anomalous group velocity dispersion (GVD) and nonlinear self phase modulation (SPM) in a lossless configuration. By analysing the transmitted output, we conclude it is possible to obtain logic gates OR for two different power-splitting ratios ρ of the coupler (ρ=0.1 and 0.2). After this step, we applied a dephasing control to the input pulses, aiming to achieve logic gates with ρ=0.3 and ρ=0.4 and to enhance the study of cases in which they had not been previously obtained. We obtained OR and AND logic gates with a phase variation study for ρ=0.1 and 0.2. For ρ=0.3 and 0.4, the variety and versatility of logic gates proved to be very broad where OR, AND and XOR gates were obtained.