This edited volume covers technological developments and current research trends in the field of photonics, plasmonics and optics focussing on photonic crystals, semiconductor optical devices, optical communications, optical sensors with an emphasis on practical sectors. It broadly contains the latest research domains contributed by the experts and researchers in the respective fields with a major focus on the basic physics. Works in the area of electromagnetic bandgap structure and metasurfaces are included for applications in different aspects of communications systems. Further, it covers research phenomena of microwave photonic devices to develop miniaturized high frequency devices.Features:Reviews non-linear optical phenomena related with materials and crystals, and plasmonic effects on device fabrications.Contains a detailed analysis on photonic crystal with its applications in making all-optical passive components.Focusses on nonlinear optics, more precisely on crystals and materials, and computational aspects on evaluating their properties from Maxwell’s equation.Presents in extensive study on physics of EBG structures for application in antenna and high-frequency communications.Includes metamaterials and metasurfaces for applications in photonics as well as in microwave engineering for high-frequency communication systems.This edited volume is aimed at researchers, professionals, graduate students in optical communication, silicon photonics, photonic crystals, semiconductor optical device, metamaterials and metasurfaces, microwave photonics.