Submarine networks: evolution, not revolution

We have described in a previous issue of the Comptes Rendus Physique of January–February 2003 how the wavelength division multiplexing technique enabled us to increase drastically the transmission capacity per fiber over trans-Atlantic distances (from 1 × 5   Gbit / s in 1995 up to 42 × 10   Gbit / s in 2001). Then, the crash of the internet bubble reduced the need for higher capacity, but, recently, the demand in trans-Pacific links has lead to the deployment of new technologies such as the differential phase shift keying modulation format. This new modulation format also enables the upgrading of existing links beyond their design capacities. We illustrate the benefit of this new modulation format and also discuss the capabilities to increase the bit rate from 10 Gb/s to 40 Gb/s per wavelength. To cite this article: O. Gautheron, C. R. Physique 9 (2008).