Textbook in PDF format This book will provide an overview of the recent developments in all-optical communication technology, relevant and critical materials, and recent and emerging applications in various domains. It focuses on all-optical communication technology and applications in the most critical domains: microwaves, meta surface, optoelectronics, and photonic fibers. It provides insight for readers about all-optical technology advancements, fabrication, challenges, applications, and future perspectives for all-optics communication in real-time applications. It also discusses the use of photonic crystals in different all-optical communication applications