This paper reviews the evolution of undersea cable technology from the telegraph cables of the mid-nineteenth century to the optical undersea cables of today. Future systems will use optical fiber amplifiers which offer significant technical and economic advantages. Consequently, emphasis is placed on problems associated with the accumulation of small, second-order effects in long lengths of optical fiber and, specifically, their impact on the 5-Gb/s optically amplified transoceanic undersea systems scheduled to be deployed in 1995. Technology options for achieving further capacity increases, among them the use of optical solitons, and trends toward networked undersea cable systems with automatic restoration features are described.>

After a brief review of the economical advantages of fiberoptic techniques in submarine links, the main characteristics of the first French submarine optical system, the S280, are discussed with special attention given to its supervisory system. Fibers, cables, and repeaters are described, notably concerning the technological choices and the performances. After two experimental links without and with submerged repeaters, the first commercial link will be provided between the mainland and Corsica, before participation in the TATS project, in 1988.

Submarine optical telecommunication cables must satisfy a large number of specific items. To comply with specifications, CDL has developed a cable structure based on high-performance optical fibers placed with slack in the grooves of a plastic rod put in the center of a very strong cable. The deep-sea cable is the basic structure for armored cables or land cables. Armor transitions are designed to minimize cable twist. The couplings are designed to give a good optical electrical and mechanical continuity between the cable and the repeaters. The deep-sea repair is designed to be achievable on a cable ship. The cables, repairs, and couplings have successfully sustained several sea trials and two experimental links are now operating. No increase of the attenuation of the optical fibers in the cable have been noticed on the 19-month old first link. The development of the S 280 cable is proceeding on the right track.