Submarine optical networks: How to make them greener

Submarine optical networks play a major part in international telecommunication networks, with over 95% of all transcontinental communications traffic being carried by submarine cables. This makes submarine optical networks highly important, both from economical, as well as the legal point of view. Due to their small size, underwater fiber-optic cables generally have negligible impact on the marine environment. However, activities associated with their design, laying, repairs and maintenance may cause pollution and sometimes even long-lasting changes in ecologically and biologically highly sensitive marine areas. This paper analyses those activities and evaluates their impact on the marine environment, also addressing possible threats to submarine cables from human activities and natural hazards. The paper provides guidelines for improving the installation of cables and their security, regarding technical and legal aspects. Sustainable use and conservation of coastal and high sea areas ensure better availability and resilience of optical submarine networks, hence making them truly green communications channels.