Environmental Impact of Coherent Point-to-Multipoint Pluggables in Metro Aggregation Optical Networks

The environmental impact of telecommunications is becoming increasingly relevant in our society as more data are transmitted every day. On the one hand, telecommunication networks help, for example, by reducing the number of travels and visits; on the other hand, the energy consumed by the network elements and devices is reaching unprecedented levels as a consequence of the growing bandwidth demand needed by novel applications and services. In this contribution, we analyze key metrics to estimate the energy efficiency, in building an optical network, of several types of optical transceivers when employed in the most common topologies of metro aggregation networks, i.e., horseshoes, rings, and hub-and-spoke. We considered three different types of coherent pluggable modules: (i) 400G ZR point-to-point (P2P); (ii) 400G ZR+ P2P; and (iii) 100G/400G point-to-multipoint (P2MP) which can be enabled by digital subcarrier multiplexing (DSCM). We show that the P2MP approach needs—due to its inherent flexibility and the ability to simplify network design—the lowest number of devices, and consequently the lowest amount of CO 2 emissions among the three considered metro aggregation network scenarios.