Ultra long distance submarine DWDM systems

In today's Internet age information flows across continents as easy as it flows across the office, thanks to undersea fiberoptic cable systems. The capacity of the next generation of undersea cables will far exceed 1 Tbit/s; a level once considered exclusively the realm of laboratory experiments. The capacity of WDM transmission systems based on digital regenerators is not infinite. This of course was due to the capacity bottleneck in the digital regenerator.