Basic requirements and options for communication systems in scientific underwater cable networks

New innovative scientific underwater cable networks have been proposed and initiated in many locations around the world. These networks have become feasible due to recent evolution of underwater telecommunication cable technology. However, their communication systems are quite different from standard telecommunication cable systems. Differences between the characteristics of existing submarine telecommunication systems and the basic technical requirements of scientific underwater cable networks will first be described. Options for the use of existing technologies include optical gigabit Ethernet (GbE) over a separate DWDM optical transport, integrated CWDM GbE transceivers and DWDM with Raman modulators. These will be presented along with their advantages and disadvantages. The present status of NEPTUNE communication system and considerations on its reliability will also be presented.