In this study, the authors propose a novel design for all-optical logic gates based on
the interference effect methodology of constructing two-dimensional "photonic crystals". The
gates consist of ellipse-shaped rods with a 45˚ orientation arranged in a square lattice. These
rods are air-filled holes drilled in a Silicon substrate. The suggested structure is engineered to
operate with Transverse Magnetic (TM) waves, which are defined such that the Transverse
Magnetic polarization of light is parallel to the rods of the design while propagating. Numerical
simulations demonstrate that the gates successfully meet their targeted truth tables at the
communication wavelength of 1550 nm (the commonly used wavelength in optical
communication). The design has ultra-small device dimensions of 4x4 µm2
, which provides the
advantage of high device speed (60~110 fs). Furthermore, our design operates with TM waves,
which are challenging to manipulate.