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Deutsche Telekom says it has set a new data transfer speed record over a long distance and outside a laboratory. The German firm says it achieved a usable bit rate of 400Gbps (gigabits per second) over a single channel of its fibre optic network. That is more than double the 186Gbps record set by researchers in the US and Canada last year. The company says it now plans to roll out the technology to ensure users can enjoy an "unclogged" service. The experiment was carried out by sending data along the company's network between Berlin and Hanover and back again - a total distance of 734km (456 miles).
The experiment delivered a maximum 512Gbps down each channel, of which 400Gbps was usable data - the spare capacity is used to provide error correction. That is the equivalent of being able to transmit 77 music CDs simultaneously within a second. Each optical fibre is thinner than a human hair but can carry a total of 48 channels - making the total potential throughput up to 24.6Tbps (terabits per second) - or the equivalent of 3,696 CDs per second.
Software upgrade
The firm says the feat was achieved by working with Alcatel Lucent to create new technologies which were installed in its terminal stations at either end of the fibre. Much of the speed gain was delivered through improvements to the software used for forward error correction - a technique that encodes and then decodes the data, allowing a limited amount of corrupted bits to be corrected without the need for the information to be resent.
"You can imagine it as squeezing and tilting the entire set-up around to get more capacity out," Deutsche Telekom's T-Labs manager Heinrich Arnold told the BBC. "It means improvements can be carried out without digging up the existing fibre, without massive hardware replacement - that's actually the charm of the thing. "Whenever we can do something where the biggest part of the infrastructure remains untouched, it means great progress becomes possible." Rather than faster broadband speeds, the firm says the key benefit for home users will be be that they notice an "available, open network" that appears to work more efficiently than at present.
BBC News - Deutsche Telekom claims record data transfer record
Todays electronic computers are built around vast numbers of transistors, etched into silicon wafers. A transistor is basically a switch used to control the electrical current flowing through a wire. It can amplify the signal strength or turn it on or off. Drew Endy and his Stanford colleagues have created what they call the transcriptor. Instead of electrical current, the device controls the flow of an enzyme - called R-N-A polymerase - along the DNA in a cell. If you imagine a DNA molecule like a wire, with this enzyme flowing along, what were going to do is were going to come in with a third signal, just like a transistor, and switch the DNA, such that the flow of the enzyme can either pass through the transcriptor or it gets blocked. And thats it, said Endy.
New places for computing
By using more than one transcriptor, the researchers were able to issue logical instructions, using concepts like and and or - concepts basic to silicon-based computers. If biological computing has a future, Endy doesnt see it embedded in your laptop or smart phone. We arent trying to replace silicon computers or mechanical computers, because they probably arent going to be as fast. Theyre not going to be as raw-powerful. But theyre going to work in places that the existing computers we have dont work. So its computing in a new space or a new place, he said. One place could be in agriculture. Endy gave an example of spirulina algae being grown in Thailand. It could be bio-engineered to change color if the water had heavy metals or other pollutants in it. And youd get a warning saying, 'you know that batch of food youre making isnt safe for people to eat.'
Food with computer apps
Applications involving human health may be further in the future, because of the need for careful safety testing. Endy said he could imagine foods with computing power that could diagnose the status of the digestive tract. [You] could have microorganisms of a sort-of biotic, coming from yogurt or something else, that would have a little bit of genetic sensing and logic and could be used to detect the disease state of your alimentary canal, your gut. Researchers also are looking at engineering human immune cells to give them a boost in the battle against cancer. The research paper by Drew Endy and his colleagues is published online by the journal Science.
Source
Researchers reporting in Nature Photonics suggest putting not one beam of light down a fibre, but a pair, each a kind of mirror image of the other. When recombined on the receiving end, the noise that the signals gather in the fibre cancels out. These paired beams can travel four times farther than a single one. The team used the technique to send a signal of 400Gb/s - four times faster than the best commercially available speeds - down 12,800km of optical fibre, farther than even the longest trans-oceanic fibre link.
What limits the distance a given light signal can go is how much power is in the beam. But the higher the power, the more the light actually interacts with the material of the fibre, rather than merely passing through it. That adds "noise" to the beam that limits the fidelity with which data can be transmitted. What is needed is a way to undo this noise, and one idea is known as phase conjugation.
Optical fibres carry huge amounts of data for their size, but data appetites grow ever more voracious
Conjugate visit
Light waves, just as sound waves and waves on the sea, consist of a pattern of peaks and troughs that can be manipulated to represent data. The "phase conjugate" of a beam is, in a sense, simply one in which every peak becomes a trough and vice versa. This is effectively the same thing that noise-cancelling headphones do: generating the inverse of incoming sound so that the two cancel out. Ideas exist to make use of phase conjugation to "undo" the noise that fibre links add, but they involve adding devices midway along the links' length - sometimes, in the middle of an ocean floor. "Sometimes you may send data from London to New York, sometimes you may send it from London to Paris. The links are changing and you cannot keep sending people to the middle of the link," said lead author on the new research Xiang Liu of Bell Laboratories in New Jersey, US. What Dr Liu and colleagues instead suggest is creating a pair of phase-conjugate beams, each carrying the same data.
And as Dr Liu explained to BBC News, the noise that each gathers is equally a mirror image of that on the other. "At the receiver, if you superimpose the two waves, then all the distortions will magically cancel each other out, so you obtain the original signal back," he said. "This concept, looking back, is quite easy to understand, but surprisingly, nobody did this before." If the noise on the beams can be undone, the power can be ramped up - making data go literally further. But since fidelity can be maintained, there can be less of the repetition of information in a given beam that is used for error correction. So the phase conjugation method is also a way to get higher data speeds. "Nowadays everybody is consuming more and more bandwidth - demanding more and more communication," Dr Liu said. "We need to solve some of the fundamental problems to sustain the capacity growth."
BBC News - Light-beam 'twins' take data farther
