Future ultra-high capacity transoceanic submarine systems

After a short summary of the main physical phenomena involved in transoceanic amplified transmission, the main characteristics and basic limitations of the first generation of 5 Gbits/s amplified submarine systems (TAT 12/13) will be described. Before the next century, the optimisation of this technology will allow cost savings through increased amplifier spacing and use of WDM for network flexibility. A second generation of submarine amplified systems could be technically feasible around year 2000, with a capacity in the 40-100 Gbit/s range. Three solutions are envisioned that could achieve this goal, dense WDM of non return to zero (NRZ) channels, filtered soliton transmission, and in line modulation of solitons. The ´pros and cons´ of these three potential solution will be detailed, together with associated experimental and simulation results already published or recently obtained.