Proposal for all-optical NOR gate using single quantum-dot semiconductor optical amplifier-based Mach–Zehnder interferometer

The feasibility of realizing an all-optical NOR gate for 160 Gb/s return-to-zero data pulses using a single quantum-dot semiconductor optical amplifier (QD-SOA)-based Mach–Zehnder interferometer is theoretically investigated and demonstrated. The proposed scheme exploits a modified Fredkin gate driven not only by the pair of data streams between which the Boolean NOR function is executed but by the complement of one of these signals as well. A numerical simulation is conducted to evaluate the performance of the scheme against the extinction ratio and find for which choice of the critical data signals and QD-SOAs parameters this metric becomes acceptable. Provided that the specified requirements are satisfied, which is technologically feasible, the NOR gate can be realized for data signals of the same wavelength both with logical correctness and high quality.