Twisting Light To Boost Bandwidth
More people are using the Internet every day for all manner of personal and business needs. At the same time, smart machines from power plant turbines to the servers running global markets are sending volumes of data every second to each other to make the modern world work. With all this communication, the digital information constantly streaming around Earth is growing beyond the capabilities of current networks.
Now researchers have developed a new way to dramatically increase the capacity of these networks—by sending multiple twisting beams of laser light called optical vortices down a specially designed optical fiber. Their innovation could mean a transmission capacity of 1.6 terabits per second, or roughly eight Blu-Ray DVDs every second.
Harnessing a property of corkscrewing light waves called orbital angular momentum (OAM), the scientists created spatially distinct streams of data-transmitting channels in a single fiber to make the terabit-scale rate. Their work was published in the June 28 issue of the journal Science.
Boston University engineering professor Siddharth Ramachandran developed the novel fiber that could propagate the optical vortices.
“For several decades since optical fibers were deployed, the conventional assumption has been that OAM-carrying beams are inherently unstable in fibers,” Ramachandran said in a university release. “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.”
The development is very important—the growth of the industrial Internet and mobile phone Internet users are driving the transmission capacity of today’s networks to their max. Previous bandwidth expansions have relied on increasing the number of wavelengths in data-carrying laser light transmissions but that method is reaching its physical limits.
Ramachandran’s team is employing another approach with OAM—sending data down separate paths within the same fiber. This, they say, will allow an entirely new degree of freedom for future fiber networks.
Top Image: Gif of optical vortices in a donut-shaped laser light beam courtesy of Prof. Siddharth Ramachandran’s Nanostructured Fibers and Nonlinear Optics Lab at Boston University.