Abstract

This tutorial will review the leading architectures for future lightwave transmission systems, networks and local access, in particular, the wavelength-division multiplexing (WDM) to be employed as a key technology. We will examine the various functionality and performance requirements for the active components. For transmission systems, accurately wavelength-selected WDM sources with low chirp and matched wavelength multiplexers and demultiplexers are required. One such important source is the integrated electroabsorption modulated laser (EML) capable of operating up to 10Gb/s while maintaining extremely small chirp. For next generation transmission and networking, a stable tunable EML with programmable wavelength will be particularly versatile and important. For access, WDM technology is also becoming very attractive. Here, the requirement is a larger number of channels, lower bit rates and, most important of all, very low cost. A very attractive source is the fiber-chirped source. More traditionally, low­cost nonhermetic packaging will be the key to low-cost lasers. For data link applications, “zero” threshold laser arrays and vertical surface emitting lasers are the leading candidates. For analog transmissions, the requirements on laser linearity and power are progressing rapidly that some breakthrough in analog source design may be needed. Center to the recent and future revolutions in lightwave systems is the advent of the fiber amplifiers. High-power 980 nm and 1480 nm pump lasers will continue to be key devices, in particular, the development of next generation 980 nm pump lasers. Recently, diode-pumped fiber lasers at 1480 nm with several watts have been demonstrated. The availability of all these high-power pump sources has enabled larger passive split fiber architectures, long-distance repeaterless spans especially in remotely pumped undersea systems and new nonlinear fiber devices.

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