A novel design of high contrast ratio quantum C2NOT (Toffoli) gate based on photonic crystals

In this paper, a novel C2NOT optical gate by using a hexagonal two-dimensional photonic crystal lattice has been introduced and analyzed. The presented structure consists of five waveguides with three inputs and three outputs. The input and output are connected by six ring resonators. By creating defects in the structure and removing the rod, ring resonators and waveguides have been created. The design was analyzed using both the finite difference time domain (FDTD) and the plane wave expansion (PWE) method. The PWE method was employed to determine the photonic band gap of the structure, while the FDTD method was used to analyze the behavior of electromagnetic fields within the photonic crystal lattice. The main advantage of this design is the high contrast ratio (contrast ratio of 13.1 dB in switching mode) and low footprint. Also, other advantages include the use of silicon with a refractive index of 3.46 in the background air, as well as increasing the maximum output power in the case of equal to one and reducing the minimum output power in the case of equal to zero presentation and design in the form of a hexagonal lattice, the use of linear materials and the use of linear defects, low delay and reduction of footprint compared to previous designs and the ability to be used in integrated circuits.