This book is a detailed description of all the aspects of ultrahigh speed optical transmission technology. Ultrahigh-speed optical transmission technology is a key technology for increasing communication capacity. The devices developed for ultrahigh-speed optical transmission are not limited to communication applications only. They are key devices for high-speed optical signal processing, i.e. monitoring, measurement and control, and will thus give a wide technological basis for innovative science and technology. All these aspects of ultrahigh-speed optical transmission technology are described in detail in this book.