Optical Majority Gate Designed Using Nonlinear Cavities

Optical logic gates are very important for all-optical communication systems. An all-optical majority gate will be proposed and designed in this paper. The proposed structure will be designed based on photonic crystal structures. The proposed structure works based on optical threshold switching which is realized using nonlinear resonant cavities. The nonlinear resonant cavities are created by adding a nonlinear defect made of doped glass that has a high Kerr coefficient. The proposed structure is simulated using Rsoft photonics CAD. The simulations are done using the finite difference time domain method. The proposed majority gate has 3 input ports and only one output port. The output port is ON, when at least two of the input ports are ON. The working wavelength of the proposed structure is 1550 nm. For the proposed all optical majority gate the ON/OFF contrast ratio and the bit rate are 19.5 dB and 500 GS/s respectively.