All-Optical Logic Gates Based on Phase Difference between Beams in Two-Dimensional Photonic Crystal Waveguides

We have proposed an all-optical switch for logic gates application using two-dimensional Photonic Crystal (PC) waveguide based on phase difference between incident beams that is created by point defect. A PC with triangular lattice made using Si dielectric rods in the air is used as the main structure of the device. Our proposed devices are XOR and OR logic gates. We have shown if initial phase difference between two inputs is π then they interfere destructively to realize the logical functions. This optical gate has many advantages than electrical logic gates such as low power consumption, high speed about light velocity and simple structure. This device is applicable in frequency range 0.44-0.46 (a/λ), but we use frequency a/λ=0.452 for low dispersion and set the lambda to 1.55 µm. The plane wave expansion method (PWE) is used to photonic band gap (PBG) calculation, and finite-difference time-domain method (FDTD) is used to compute the electrical field distribution in the photonic devices. The designed gates can be used in the photonic integrated circuits (PIC).