New fibre optic technology to boost internet bandwidth
Scientists have devised a new fibre optic technology that
promises to increase internet bandwidth dramatically.
WASHINGTON:
In a breakthrough, scientists -- including one of Indian origin -- have devised
a new fibre
optic technology that promises to increase bandwidth dramatically, easing internet
congestion and video streaming.
The technology centers on donut-shaped laser light beams called optical
vortices, in which the light twists like a tornado as it moves along the beam
path, rather than in a straight line.
Widely studied in molecular biology, atomic
physics and quantum optics, optical vortices (also known as orbital angular
momentum, or OAM, beams) were thought to be unstable in fibre, until Boston
University engineering professor Siddharth Ramachandran recently designed
an optical fibre that can propagate them.
In a paper in journal Science, he and Alan Willner of University of Southern
California, demonstrated the stability of the beams in optical fibre and also
their potential to boost internet bandwidth.
"For several decades since optical fibres were deployed, the conventional
assumption has been that OAM-carrying beams are inherently unstable in
fibres," said Ramachandran.
"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 fibres," he said.
Ramachandran and Willner collaborated with OFS-Fitel, a fibre optics company in
Denmark, and Tel Aviv University.
Traditionally, bandwidth has been enhanced by increasing the number of colours,
or wavelengths of data-carrying laser signals -- essentially streams of 1s and
0s -- sent down an optical fibre, where the signals are processed according to
colour.
An emerging strategy to boost bandwidth is to send the light through a fibre
along distinctive paths, or modes, each carrying a cache of data from one end
of the fibre to the other.
Unlike the colours, however, data streams of 1s and 0s from different modes mix
together; determining which data stream came from which source requires
computationally intensive and energy-hungry digital signal processing
algorithms.
Ramachandran and Willner's approach combines both strategies, packing several
colours into each mode, and using multiple modes.
In experiments in the study, researchers created an OAM fibre with four modes
(an optical fibre typically has two), and showed that for each OAM mode, they
could send data through a 1km fibre in 10 different colours, resulting in a
transmission capacity of 1.6 terabits per second.
A robot that views maps in 3D
Researchers have developed humanoid robots in the world that
maps reference relative to its surroundings.
LONDON:
Researchers have developed one of the most
advanced humanoid robots in the world that maps reference relative to its
surroundings and is able to "remember" where it has been before.
Computer vision algorithms enable the latest humanoid robot, Roboray, developed
by researchers from the University of Bristol, to build real-time 3D visual
maps to move around more efficiently.
The ability to build visual maps quickly and anywhere by using cameras is
essential for autonomous robot navigation, in particular when the robot gets
into places that have no global positioning system (GPS) signals or other
references.
Roboray is one
of the most advanced humanoid robots in the world, with a height of 140cm and a
weight of 50kg. It has a stereo camera on its head and 53 different actuators
including six for each leg and 12 for each hand, researchers said.
The robot features a range of novel technologies. In particular it walks in a
more human-like manner by using what is known as dynamic
walking. This means that the robot is falling at every step, using gravity to
carry it forward without much energy use.
This is the way humans walk and is in contrast to most other humanoid robots
that "bend their knees to keep the centre of mass low and stable."
This way of walking is also more challenging for the computer vision algorithms
as objects in images move more quickly.
"A humanoid robot has an ideal shape to use the same tools and spaces
designed for people, as well as a good test bed to develop machine intelligence
designed for human interaction," Dr Walterio Mayol-Cuevas, deputy director
of the Bristol
Robotics Lab, said.
"Robots that close the gap with human behaviours, such as by featuring dynamic walking, will not only allow more energy efficiency
but be better accepted by people as they move in a more natural manner,"
said Mayol-Cuevas.
The technology of rapid 3D visual
mapping is internationally renowned because of its ability to robustly
track and recover from rapid motions and occlusions, which is essential for
when the humanoid moves and turns at normal walking speeds, researchers said.
The study was published in the journal Advanced Robotics.
