The book presents the detailed study of optoelectronic gyroscopes, especially Ring Laser Gyroscopes (RLGs) and Fiber Optic Gyroscopes (FOGs). It discusses their design in detail to optimize their performance, besides explaining the related concepts and the new developments. Other topics covered in this book are double ion beam sputtering for fabricating RLG mirrors on the high quality optical substrates, optical testing, and thin films characterization techniques. The book will be useful for the researchers, professionals, and engineers working in the areas of optical gyroscopes and the related technologies.