Photonic crystal logic gates: an overview

Photonic crystals are considered as the suitable structures for creating all-optical processors because of low loss and high capability in guiding and controlling the light. This paper contains a comprehensive review of the principles, different types of designing methods and operational improvements of optical logic gates. The presented designs are investigated and categorized into three groups of all-optical photonic crystal logic gates based on interference waveguides, resonator structures and self-collimation phenomenon. Two former structures can be designed by utilizing linear or nonlinear materials while the later one performs just in linear regime and is independent from the input beam intensity. In general, the main purpose of previously accomplished studies has been presenting the designs to be resulted in broad operational bandwidth, low power consumption, high switching speed, high contrast ratio and excellent integration capability by trading off between different parameters. Also a comprehensive study has been done on the advantages and disadvantages of different design methods.