19. Energy Efficiency in Optical Networks

Energy efficiency is important for optical networks in terms of scalability, low-cost operation, and sustainability. At the same time, optical networks play an important role in enabling energy efficiency for the Internet as a whole and for information and communication technologies more generally. Understanding energy in the context of optical networks begins with an understanding of the constituent components and equipment that make up an optical network and how their energy use is evolving over time. The network architecture, describing how these parts are put together and operated, will also have a considerable impact on the energy efficiency of optical networks. This impact can be modeled and understood in different ways. Perhaps the largest energy impact, however, comes from including optical networks in cross-layer design and survivability strategies. These aspects of energy-efficient optical network design are examined, along with issues related to mobile and optical network convergence, nonlinear optics and optical processing, and computer and optical network cross-optimization. An introduction to resources for recommendations and guidance from standards bodies and other organizations on the energy efficiency of optical networks is also provided.