It was in the late 1980s that the concept of code-division multiple-access (CDMA) techniques was proposed in optical communications. Since then we have witnessed rapid and dramatic advances in optical fibre technologies. To provide a comprehensive and up-to-date progress report of optical spreading codes, optical modulations and transceiver architectures, we have decided to publish this new book which in fact is a broad extension to the current state of optical CDMA (OCDMA). The main objective is that this new book should serve both as a textbook and a reference monograph. As a result, each chapter is designed to cover both physical understanding and engineering aspects of coding, modulations and system structure.
With the rapid growth and sophistication of digital technology and computers, communication systems have become more versatile and powerful. This has given a modern communication engineer two key problems to solve: (i) how to handle the ever-increasing demand for capacity and speed in communication systems and (ii) how to tackle the need to integrate a wide range of computers and data sources, so as to form highly integrated heterogeneous communication networks with a global coverage.
The foundations of communication theory show that by increasing the frequency of the carrier used in the system, both the speed and the capacity of the system can be enhanced. This is especially true for modern digital communication systems. As the speed of computers has increased ...