Recommendation ITU-T G.977.1 provides physical layer specifications for dense wavelength division multiplexing (DWDM) applications on dispersion-unmanaged repeatered optical fibre submarine cable systems. Transverse compatible applications for DWDM applications for repeatered optical fibre submarine cable systems are described for point-to-point, multichannel line systems with optically pumped amplifiers. The primary purpose is to enable multiple vendors to design DWDM transmission equipment for submarine fibre links that are compliant with this Recommendation.