Last week, Nature Communications published a paper on a new device that promises to effectively utilize fiber optics in order to dramatically influence the future of the Internet, making Internet speeds 100x faster than today. Australia’s RMIT university of technology and design announced its innovation: the world’s first nanophotonic device to use a form of ‘twisted’ light to encode more data and process it incredibly quickly.
Twisted Light and the Speed of the Internet
The device is the work of a research team led by Dr Haoran Ren from RMIT’s School of Science and Dr Zengji Yue, Associate Research Fellow at the University of Wollongong.
Today’s broadband fiber optics transmit information on pulses of light through optical fibers. The way in which the light is encoded at one end and processed at the other affects the speed of transmission, so they only use a fraction of light’s actual capacity.
The nanophotonic device from RMIT, however, is capable of reading twisted light using the oscillation of light waves to encode data. This allows it to unlock a great deal more of light’s actual data-carrying capacity than merely the color spectrum accessed by today’s broadband technologies. The data being carried on light waves are twisted into a spiral, a state the researchers refer to as “orbital angular momentum (OAM)”.
OAM is best explained in relation to the Earth-Sun system: our planet spins on its axis in spin angular momentum, however, the orbital angular momentum is witnessed in the earth’s revolution around the sun. “Twisted light” approaches use the same kind of OAM.
Previous Advances in the Field
In 2016, the same group of researchers from RMIT’s Laboratory of Artificial-Intelligence Nanophotonics (LAIN) published a research paper in Science Journal describing their ability to decode a small range of twisted light on a nanophotonic chip.
In 2011, Dr. Siddharth Ramachandran of Boston University partnered with fiber company OFS Fitel to produce a fibers-within-fibers design, adding chemicals to each concentric ring that altered the speed of light in each concentric circle. These new fibes provide different paths for different beam twists. He joined forces with Allan Wilner of USC who led the team in an “over-the-air” demonstration in 2012.
“It was a nice collaboration between a fibre 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 Prof Willner.
By showing that the “twisted light” idea could work in optical fibres. The light is corkscrew-shaped, allowing more data to be encoded within the differently twisted beams. A team reporting in Science revealed data rates of 1.6 terabits per second using 10 different colors, each with two levels of twist, over 1km of optical fibre. Impressive proof that the technique could be used with fibres in data centers.
“There may be certain areas where there are more or less closed systems where you need more bandwidth,” Prof Willner said. “If you have a Google data centre, say, where you need terabits between servers, you envision that might be where newer types of fibres might find a place.”
In 2014, scientists obtained speeds of 2.56 terabits per second (2, 2560 gigabits per second) using light-wave signals that were spun into the shape of a corkscrew. After an unwieldy open-air experiment, the group tried the same technique in the medium of radio where they obtained speeds of 32 gigabits per second.
Radical Breakthrough for Industrial Applications
However, technology to detect a wide range of OAM light for optical communications was still not viable, until now.
“Our OAM nano-electronic detector is like an ‘eye’ that can ‘see’ information carried by twisted light and decode it to be understood by electronics,” said Min Gu, the Associate Deputy Vice-Chancellor for Research Innovation and Entrepreneurship at RMIT. At its most fundamental level, the device is constructed to differentiate between different types of OAM light state in a continuous order to extract the data they carry.
Until now, this was not believed to be possible. “To do this previously would require a machine the size of a table, which is completely impractical for telecommunications. By using ultrathin topological nanosheets measuring a fraction of a millimeter, our invention does this job better and fits on the end of an optical fiber,” explained Ren.
The reason for the breakthrough is indeed that the RMIT group has miniaturized the equipment. The experiments of previous academic teams have all involved larger transmission and decoding equipment, which would have been impractical for current telco environments, according to RMIT.
Its promise for industrial scaling is significant as the device’s materials are compatible with popular silicon-based options. “This technology’s high performance, low cost and tiny size makes it a viable application for the next generation of broadband optical communications,” Gu said.
A Fix to Capacity Challenges?
Scientists say that the research can be implemented to upgrade existing networks and dramatically boost efficiency in a straightforward way.
“Present-day optical communications are heading towards a ‘capacity crunch’ as they fail to keep up with the ever-increasing demands of Big Data,” said Ren. “What we’ve managed to do is accurately transmit data via light at its highest capacity in a way that will allow us to massively increase our bandwidth.”
Welcome news in the era of the rise of the Internet of Things, AI and ever increasing amounts of big data.