Ultrasmall optical logic gates based on silicon periodic dielectric waveguides

An ultrasmall silicon periodic dielectric waveguides-based multimode interference all-optical logic gate has been proposed. The device consists of three 205 nm wide single-mode input waveguides, a 1.1 μm wide and 5.5 μm long multimode interference waveguide, and three 205 nm wide single-mode output waveguides. The total length and width of the device are 13.7 μm and 3.2 μm, respectively. By changing the states of the input optical signals and/or control signals launched into the device, multifunctional logic functions including OR, NAND, NOR, and NOT gates are performed, and each logic function can be realized at a specific output waveguide in accordance with the launched control signals. The ultrasmall multifunctional logic device has potential applications in high density photonic integrated circuits.