Design of ultra compact all-optical XOR and AND logic gates with low power consumption

We propose a novel ultra-compact all-optical XOR and AND logic gates without using nonlinear optics. In order to realize these devices, we adopt photonic crystal waveguides (PCWs) based on multi-mode interference devices. Numerical results show that the operating bandwidth of the ON to OFF logic-level contrast ratio of not less than 6.79 dB is 35 nm for XOR logic gate and 9 nm for AND logic gate. Proposed logic gates have the potential to be key components for an optical packet switching system due to their small feature sizes and low power consumption.

Research highlights
► We design ultra compact all-optical XOR and AND logic gates.
► We adopt photonic crystal waveguides based on the multi-mode interference.
► We bring in the genetic algorithm to improve transmission characteristics.
► For XOR logic gate, the useful operating bandwidth is 35 nm.
► For AND logic gate, the useful operation bandwidth is 9 nm.