Realization of all optical silicon slab waveguide based universal logic gates

In this paper the design and implementation of SSW based all-optical NAND and NOR logic gates have been proposed. The design leverages the properties of silicon's high refractive index at optical communication wavelengths (1.55 µm), which ensures low critical angles and enhanced optical confinement in slab waveguides. The gates operate on the interference of the input signals. The designed NAND and NOR logic gates have been optimized for performance in both TE and TM modes using FDTD software MEEP. The NAND logic gate exhibits a contrast ratio of 34.79 dB with a modulation depth of 97.11% for TE mode and 38.42 dB with a modulation depth of 97.11% for TM mode. The NOR logic gate exhibits a contrast ratio of 40.91 dB with a modulation depth of 98.34% for TE mode and 38.42 dB with a modulation depth of 98.60% for TM mode. The designed universal logic gates exhibit high-speed performance, with propagation delay times measured in femtoseconds. The proposed gates exhibit higher performance metrics significantly outperforming existing optical logic gate designs.