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Internet bandwidth could be increased by twisting

Internet bandwidth could be increased by twisting

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News & Events - Engineering News

July 2, 2013

For millions of people, the speed of connection to the World Wide Web is one of the most important things in their lives. In what seems like a remarkably short space of time, humanity has gone from being satisfied with watching a digital picture appear on a computer screen over a period of minutes to demanding that movies, videos and news events are available at the exact moment that they want them.

In terms of how communication has evolved in the last 20 years, it is probably fair to assume that increased connectivity is one of the defining traits of society, and internet providers have devoted enormous amounts of engineering resources to satisfying consumer demand while maintaining bandwidth integrity. As the need for speed becomes a marketing tool, fiber-optic cables have often struggled to cope with the amount of data that is required, with users accessing the Web through a number of mobile devices and media channels.

However, the days of internet congestion and web pages that take more than 60 seconds to load could soon be numbered.

Twisted light
Collaborative engineering research conducted by scientists at Boston University and the University of Southern California has produced a means of transmitting data though fiber-optic cables by using a "twisted light" technique, in other words adapting the flow from a conventional straight line into a spinning stream that resembles a tornado or a corkscrew.

The research, which has been published in the journal Science, relies on the fact that photons - the basic units of light - have two forms of movement; spin angular momentum or polarization and orbital angular momentum. In terms of how this applies to internet bandwidth, scientists have considered just how data is transmitted through the cables, with the theory being that sending these data-carrying light beams down a fiber-optic cable should not be restricted to pre-determined paths but instead could rely on multiple modes of transmission known as optical vortices.

"For several decades since optical fibers were deployed, the conventional assumption has been that OAM-carrying beams are inherently unstable in fibers," said Siddarth Ramachandran, a professor of engineering at BU. "Our discovery, of design classes in which they are stable, has profound implications for a variety of scientific and technological fields that have exploited the unique properties of OAM-carrying light, including the use of such beams for enhancing data capacity in fibers."

According to the BBC, the research could prove to be an important step forward in terms of how high quality data - such as demanded by consumers in terms of streaming - can be transmitted. With millions of miles of fiber-optic cable already installed underground and under the global oceans, the experimental technique, which has been funded by the U.S. Defense Advanced Research Projects Agency, is already being seen as one way in which bandwidth could be boosted.

Data transmission rates
It should be noted that while the process is still in the early stages of development, specially-designed fibers may need to be developed. The research team is currently able to demonstrate data transmission rates of 400 gigabytes per second with a single light color and four levels of "twist," and 1.6 terabytes per second with 10 colors and 2 twists - the equivalent  of sending eight Blu-Ray DVDs every second.

"It was a nice collaboration between a fiber expert and a systems communications group, to demonstrate that not only is orbital angular momentum able to propagate, but that the data contained within it would be of high quality," said professor Alan Willner, of the University of Southern California, in an interview with the BBC. "There may be certain areas where there are more or less closed systems where you need more bandwidth. If you have a Google data center, say, where you need terabits between servers, you envision that might be where newer types of fibers might find a place."

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