Introduction

Optical microresonators have demonstrated great promise as fundamental building blocks for a variety of applications in photonics. They can be implemented for such diverse applications such as lasers, amplifiers, sensors, optical channel dropping filters (OCDFs), optical add/drop (de)multiplexers (OADMs), switches, routers, logic gates, and artificial media. For brevity and in keeping with their current usage in the literature of this field, we specialize the term “microresonators” and generalize the term “microring resonators.” We use these terms interchangeably in this book to refer to any of a number of compact geometries that support cyclically propagating modes that close on themselves in a ring-like geometry.