Reconfigurable all-optical NOT, XOR, and NOR logic gates based on two dimensional photonic crystals

Photonic crystals can be considered as one of the most important basis for designing optical devices. In this research, using two-dimensional photonic crystals with triangular lattices, ultra-compact logic gates are designed and simulated. The intended structure has the capability to be used as three logical gates (NOT, XOR, and NOR). The designed structures not only have characteristics of small dimensions which make them suitable for integrated optical circuits, but also exhibit very low power transfer delay which makes it possible to design high speed gates. On comparison with the previous works, our simulations show that at a wavelength of 1.55μm, the gates indicate a time delay of about 0.1 ps and the contrast ratio for the XOR gate is about 30 dB, i.e., the proposed structures are more applicable in designing low error optical logic gates.