TABLE OF CONTENTS The preceding chapters have presented the fundamental characteristics of individual building blocks of an optical fiber communication link and various concepts, such as WDM, for implementing links. This chapter describes how these individual parts can be put together to form complete optical fiber transmission links. The main emphasis is on digital systems.
First Sec. 16.1 looks at the design criteria for a point-to-point link. This includes examining the components that are available for a particular application and seeing how they relate to the system performance criteria (such as bit error rate and dispersion). Section 16.2 then shows that for a given set of components and a specified set of system requirements, one can carry out a power budget analysis to determine whether the designed fiber optic link meets the allowed attenuation across the link or if amplifiers are needed periodically to boost the power level. Next Sec. 16.3 describes how to perform a system rise-time analysis to verify that the overall bandwidth requirements are met.
Section 16.4 addresses line-coding schemes that are suitable for digital data transmission over optical fibers. These coding schemes are used to introduce randomness and redundancy into the digital information stream to ensure efficient timing recovery and to facilitate error monitoring at the receiver.
To increase the end-to-end fidelity of an optical transmission line, forward error correction (FEC) can be used if the bit error rate is limited by optical noise and dispersion. This is the topic of Sec. 16.5.
Owing to the complexity of...
