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เนื้อหาย่อ : The last two decades have seen a phenomenal increase in the transmission of electronic information--a trend that is now, thanks to the Internet, growing exponentially. Traditional communication links are incapable of satisfying the demand for this information, due to the limitations imposed by their bandwidth constraints. Data transmission limitations of tra- ditional links have been overcome since the introduction of optical fiber networks. Studies have demonstrated that the information carrying capacity of optical fiber networks has increased 50% per year over the last decade. Current and projected demands for high capacity links and their antici- pated economic benefits have triggered a flurry of activity among researchers. It is the purpose of this text to present a comprehensive account of both the theoretical and the prac- tical aspects of optical communications. This volume is intended for several different audiences. It can be used by undergraduates beginning their study of fiber optics communications and also by advanced graduate stu- dents. It can also be used as a convenient reference source for academics and practicing engineers. The text covers a broad range of integrated materials relevant to optical fiber commu- nications and can be used systematically or, because each chapter has been written independently, selectively. The text is organized into four main parts: Introduc- tory Concepts, Electro-optics, Optics, and Systems. The fundamentals of optics are presented in Chapters 1-4. In Chapter 1, the elements of geometric, physical, and quantum optics are introduced as preparation for the more advanced topics in subsequent chapters. Chapter 2 in- troduces the basic concepts of atomic and semiconductor theory. Because the key devices of optical fiber systems are based on semiconductors, it is essential that topics such as energy bands, Fermi-Dirac distribution, nondegen- erative and highly degenerative semiconductor materials, the PN-junction, and biasing techniques be discussed in depth. The theory and operating characteristics of two types of optical sources, those of the LED and laser diodes, are discussed in Chapter 3. The structure and performance characteristics of edge emitting and surface emitting LEDs are also discussed. The chapter concludes with a detailed discussion of Fabry-Perot lasers, distributive feedback lasers, and multi-quantum well vertical cavity service emitting lasers. Chapter 4 is primarily devoted to a discus- sion of the photodetection process and the examination of the theory and performance characteristics of PIN and avalanche photodiodes. The structure and operating char- acteristics of advanced photodetecters, including reso- nance cavity enhanced heterojunction are also presented in this chapter. The concept of optical amplification and its imple- mentation is presented in Chapter 5. This chapter is devoted to the theory and performance characteristics of available bandwidth, dynamic range, and signal to noise ratios of semiconductor amplifiers and erbium doped fiber amplifiers. Optical transmitters and the fundamental building blocks are presented in some detail. Several types of transmitters developed by leading manufacturers, design philosophy, operating characteristics, and intended applications are discussed, along with a brief description of Lucent Technologies' uncooled laser transmitter. Chapter 7 begins with a description of basic data patterns and their differences and similarities, and continues with description of the role of optical receivers in a fiber communications system. The classification of optical re- ceivers is also discussed, followed by the presentation of several transimpedance preamplifiers and postamplifiers developed by industry as essential blocks of optical amp- lifiers. The function within a fiber optics link, the building blocks, and operating characteristics of optical trans- receivers is the topic of Chapter 8. Classification of opti- cal transreceivers in terms of their optical source discussed, followed by a discussion of a number of LED and laser based transreceivers from several manufacturers. The theory, fabrication, and operating characteristics of optical fibers are the subjects of Chapter 9. Fundamental laws governing the transmission of light through fibers and the classification of fibers as single-mode or multimode fibers are presented. Limitations of standard fiber trans- mission capabilities are identified, and the incentives for the development of advanced fibers such as non-zero dis- persion shifted and large area fibers are discussed. The chapter concludes with a detailed description of the adverse effects of four wave mixing, cross phase modula- tion, and self phase modulation in dense wavelength divi- sion multiplexing systems. Chapter 10 presents the theory and operating charac- teristics of external modulators, an essential element of high speed optical communications systems. The chapter