Recommendation ITU-T G.973 is concerned primarily with the system performance and interface requirements of repeaterless optical fibre submarine cable systems. It considers both single wavelength systems (SWS) , wavelength division multiplexing systems (WDMS) , and dense wavelength division multiplexing systems (DWDMS). It also covers the aspects related to the applications of discrete optical fibre amplifiers (OFAs) (power amplifiers, pre-amplifiers, remote optically pumped amplifiers) and/or distributed remotely pumped OFAs using Raman amplification. This edition of the Recommendation introduces a new power budget template for the implementation of coherent systems.