"Paradigms of 40/100 Gbps deployments on France Telecom long-haul transport network: Overcoming transmission impairments while adapting network architecture and analyzing economical impact"

While 40 Gbps deployments are massively starting on the carriers' transport infrastructure equipment suppliers are working hardly on the next generation of WDM transmission systems able to carry 100 Gbps per wavelength. Equipment manufacturers have converged very rapidly at 100 Gbps towards the optimal technique based on coherent DP-QPSK, owing to the experience accumulated on 40 Gbps. Nonetheless, even if 100 Gbps coherent DP-QPSK is very resilient to both PMD and CD, its future deployment raises some questions around price points, transmission reach and impacts to coexistence in the same WDM system of 10, 40 and 100 Gbps channels. These questions as well as the need to find the optimum combination in future ultra high bit-rate networks of the electrical and optical network elements' functionality balancing cost, performance, flexibility, simplicity, energy efficiency wil be discussed in this presentation.