GIGA-5 - A 5 GBIT/S TRANSOCEANIC SUBMARINE TRANSMISSION-SYSTEM

This article presents the main features of the Alcatel submarine system at 5 Gbit/s. The characteristics of optical amplifiers with Erbium doped fiber are firstly described. Then the impact, on propagation, of both the non regeneration due to optical amplification and the high bit rate, is discussed. Five points are of importance : optical noise, chromatic dispersion, polarisation dispersion, optical non linearities of the fiber, spectral width of the optical signal. The use of error correcting codes allows error-free transmissions to be obtained, even if the propagation conditions are poor. The architecture of the terminal equipment is presented, including : multiplexing equipment, 5 Gbit/s transmitter and receiver, redundancy and line monitoring equipment. The main characteristics of the repeater and its components are given. The possible evolutions of submarine systems are briefly approached to conclude.