Energy efficient optical access and metro networks

A common consensus is that the utilization of communication networks in place of human travel, if possible, is one of the means of reducing GreenHouse Gas (GHG) emissions. Therefore a more efficient energy utilization in communication networks would have the double effect of not only lowering the energy consumption of the Information and Communications Technology (ICT) sector itself but also to lower the carbon footprint of many human activities. The deployment of optical networks in place of electronic networks is foreseen as a means for reducing communications network energy consumption. However even the energy consumption of optical networks can be optimized. In this paper current initiatives in optimizing energy utilization in optical networks are surveyed. Then two use cases are presented. The first one shows that allowing Optical Network Units (ONU) to switch to sleep-mode (i.e., stand-by), through hardware and control protocol, sensibly reduces optical access network energy consumption. The second one shows that a careful combination of optical and electronic devices during the design and the deployment of metro networks can lead to an optimal energy consumption.