Dense Wavelength Division Multiplexing Networks: Principles and Applications

The very broad bandwidth of low-loss optical transmission in a single-mode fiber and the recent improvements in single-frequency tunable lasers have stimulated significant advances in dense wavelength division multiplexed optical networks. This technology, including wavelength-sensitive optical switching and routing elements and passive optical elements, has made it possible to consider the use of wavelength as another dimension, in addition to time and space, in network and switch design. The independence of optical signals at different wavelengths makes this a natural choice for multiple-access networks, for applications which benefit from shared transmission media, and for networks in which very large throughputs are required. In this paper, we review recent progress on multiwavelength networks, some of the limitations which affect the performance of such networks, and present examples of several network and switch proposals based on these ideas. We also discuss the critical technologies that are essential to progress in this field.