Monday, September 26, 2011

#OPTICS: "World's First Nanoscale Optical Fibers'

Photonic chips that compute with light instead of electricity--the holy grail of optics--will enable a faster, more sustainable Internet, by virtue of lowering its power consumption with the world's smallest optical fibers.

Researchers have created nanowires generated by direct laser writing, here stacked to form a three-dimensional woodpile photonic crystal with a pronounced stop gap.

At its current rate of growth, the Internet is on track to consume half the world's energy in the next decade, according to professor Min Gu, the Director of the Centre for Micro-Photonics at Swinburne University of Technology. To head off the debacle, Gu's research group has created the world's smallest optical fibers, which he claims will enable not only a faster, but a more sustainable Internet, by virtue of reduced energy consumption.
"The Internet has become a major energy consumer," said Gu. "In the next decade the Internet will account for half of the world’s energy usage--so making it more efficient will make a huge difference to our carbon footprint."

Researchers have created nanowires generated by direct laser writing, here stacked to form a three-dimensional woodpile photonic crystal with a pronounced stop gap.
His research team, which was recently ranked among the top 100 universities for physics research in the Academic Ranking of World Universities published annually by the Shanghai Ranking Consultancy, is working with the six university, Australian government funded, effort to stem Internet power consumption at the Centre for Ultrahigh bandwidth Devices for Optical Systems. The aim of CUDOS is to create an all-photonics Internet that drastically cuts energy consumption by computing with light instead of electricity.
Photonics encodes the binary ones and zeros of Internet communications on pulses of light instead of electronic charge packets. Electricity must overcome the resistance of the wires through which it travels, which causes them to heat up, wasting much of the energy required for communications signals. As a result, all long-haul Internet communications today are performed with optical fibers which carry signals between metropolitan areas faster and without all the heat.
However, once the signals reach their target city, they are translated into electrical signals with expensive, power hungry converters which receive the weightless photons of light from the long-haul fibers and translate them into electrical signals that travel down a cable- or digital-subscriber link (DSL) to the user's computer. Likewise, between distant metropolitan areas "repeaters" must periodically translate the optical signals into electrical ones, then use high powered lasers to re-encode the electrical signals as light pulses that continue down fibers to the next repeater.
The holy grail of photonics is to eliminate the need for repeaters, cable, DSL and even the wires between the chips inside your computer with nanoscale optical fibers that perform all computing with light, eliminating the need to ever translate weightless, energy conserving photons into heavy, energy wasting electrons. With optical fibers small enough, even the communications signals on the processor inside your computer could be made optical, saving energy for computers, routers, and other communications equipment as well as extending the battery life of the mobile device themselves.
In its most recent step toward realizing the dream of all-optical computing, doctoral candidate Elisa Nicoletti working on a CUDOS project in Gu's lab, created the world's smallest optical fibers. Measuring just 68 nanometers in diameter, the new optical fibers are small enough to be used inside all-optical routers, switches and other future photonic microchips. Measuring just one-twelfth the wavelength of the light being transmitted through them, the nanofibers were directly written with a laser onto microchips using a nonlinear material called a chalcogenide.
Other groups have created nano wires out of plastic, which is a passive material that merely passes the signal. But by using chalcogenide, Gu's group was able to demonstrate nanowires constructed into a three-dimensional "woodpile" photonic crystal with a pronounced stop gap. Such structures can work with laser-powered light pumps to perform all the functions performed today with power-hungry electrical routers and switches.
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