Pull-up network inspired all-optical logic gates based on photonic crystals

In this work we propose what is believed to be a novel concept of implementing all-optical logic gates based on the design principle of pull-up network of electronic logic circuits. The proposed concept relies on the linear interference property of light in photonic crystals, and does not require any non-linear optical medium. Based on this concept, we present conceptual descriptions of all-optical universal logic gates (NAND and NOR) and the XOR gate, and explain how the theoretical framework applies for implementing other logic gates. As a proof of concept, we designed logic gates employing silicon nanorod-in-air based periodic structures and performed electromagnetic simulations based on finite-difference time domain technique to evaluate their figure of merits (FoMs) in terms of contrast ratio, footprint and bit error rate. We have shown that the proposed technique offers a generalized approach of realizing all-optical logic gates having reasonably small footprint, high contrast ratio, and enhanced scalability.