"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 1:55 mm, 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."