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.
Keywords: Photonic crystals – 'all-Optical' logic gates– TM–ultra-small devices- compact design