Coherent lightwave communications systems incorporate the major advantages of both lightwave and radio communications, providing more powerful system capabilities such as higher receiver sensitivity and larger transmission capacity. This resource describes in detail the engineering aspects of coherent lightwave communications systems, from fundamental principles through to future prospects. It presents recent research and development data, and gives a detailed look at the devices, problems, applications, and field trials of this rapidly advancing technology. "Coherent Lightwave Communications Systems" includes systematic coverage of all the key research and applications issues, including: modulation/demodulation schemes and bit-error-rate expressions in coherent systems; lasers and receivers for coherent systems; application of optical amplifiers to coherent systems; the effects of optical nonlinearities on coherent systems; comparisons between coherent and intensity-modulation/direct-detection (IM-DD) systems; and historical progress and future prospects of coherent systems. The book also includes a complete list of coherent field trials to date and describes the latest application of the technology to optical measurement systems. More than 235 equations are presented, along with 132 informative figures and over 300 references to the literature.