Bell Labs Transmits 100 Petabits per Second

Scientists from Alcatel-Lucents research arm, Bell Labs, set an amazing optical transmission record of more than 100 Petabits per second.kilometer (equivalent to 100 million Gigabits per second.kilometer), which bodes well for the future health of the Internet backbone. The transmission is the equivalent of 400 DVDs per second being sent over 7,000 kilometers, about the distance between Paris and Chicago, a speed exceeding todays most advanced commercial undersea cables by a factor of ten.

Researchers made use of new detection techniques and an array of technologies in modulation, transmission, and signal processing A Bell Labs facility in Villarceaux, France used 155 lasers, each operating at a different frequency and carrying 100 Gigabits of data per second, to enhance the performance of standard Wavelength Division Multiplexing (WDM) technology.

"There is no question that this record breaking transmission is a milestone in achieving the network capacity and speeds and a key step forward in satisfying the ongoing explosion in demand", said Gee Rittenhouse of Bell Labs Research. "This is a prime example of Bell Labs preeminent research and demonstrates the ability of our researchers to solve complex problems", he said.

The speed figure was derived by multiplying the number of lasers by their 100 Gigabit per second transmission rate and then multiplying the aggregate 15.5 Terabit per second result by the 7000 kilometer distance achieved. The network featured repeaters, devices used to sustain optical signal strength over long distances, spaced 90 kilometers apart, 20% further than that commonly used in such networks. The challenge of maintaining transmission over these distances was appreciably greater in these experiments because of the noise perturbation of signals that is introduced as transmission speeds increase.

The researchers also increased capacity by interfacing advanced digital signal processors with coherent detection, a new technology that makes it possible to acquire details for a greater number of properties of light than the direct detection method commonly applied in todays systems. Using this technique the researchers were able to effectively increase capacity by increasing the number of light sources introduced into a single fiber yet still separate the light into its constituent colors when it reached its destination.