Guest Editorial: Multi-Band Optical Networks

The papers in this special section focus on multi-band optical networks. The papers introduce the key challenges, trends, and innovations. Current deployed networks are reaching the saturation of their capacity with the continuous bandwidth demand increase. However, the installation of new infrastructures or fibers requires high investments from network operators. Thus, alternative solutions to cope with the enormous bandwidth demand are needed. Currently, single-mode fibers (SMF) are mainly used in the C band, where SMFs present the minimum attenuation. The exploitation of other bands (e.g., L, S, E and O) may be an effective solution for network upgrade while postponing the installation of new fibers. As L-band technologies are widely deployed today, there is a rising interest in considering other optical bands (e.g., S and E) in the following years to scale capacity. Multi-band (MB) optical networking is therefore feasible considering that many of the currently deployed fibers (e.g., G.652.D fibers) do not present the absorption peak (occurring mainly in the E band).