All-optical logic operations based on silicon-on-insulator waveguides

Silicon waveguides are particularly appealing for the implementation of all-optical (AO) signal processing devices and switches due to the improved fabrication technology of silicon. Therefore, a silicon-on-silica waveguide is employed as the building block for simulating fundamental AO logic operations, including XOR, AND, OR, NOT, NOR, NAND, and XNOR, at 1.33-μm telecommunications wavelength. The proposed waveguide consists of two microring resonators and three strip waveguides. The operation concept of these logic gates relies on the constructive and destructive interference that results from the phase difference induced by incident optical beams. The performance of the target logic gates is assessed against the contrast ratio (CR) metric. The simulation results suggest that, by exploiting the proposed waveguides, these gates can operate with higher CR and faster speed compared to other designs.