Once again we
get to switch out the box and increase capacity tenfold. Yet the end may even be in sight and perhaps
it is time to think out another capacity building binge. After all, the advent of the holodec will
demand a massive increase in capacity in about twenty years at most.
The build out
will likely wait until that need is apparent of course as it is difficult to
imagine any other consumer need not already falling inside our capacity
parameters. We have big screen and we
have Netflix and we have cloud access for everything.
Thus this
advance could well keep the industry well over built for some time.
Pointy pulses
improve optical fiber throughput by a factor of 10
December 5, 2013
As the volume of data carried around the world via
optical fibers continues to increase, researchers at the Swiss Federal
Institute of Technology in Lausanne (EPFL) have found a way to increase data
throughput capacity by ten times. Because it is based on changing the shape of
light pulses to reduce the space between, the breakthrough would work on
existing optical fiber infrastructure.
"Since it appeared in the 1970s, the data
capacity of fiber optics has increased by a factor of ten every four years,
driven by a constant stream of new technologies," says Camille Brès, of the EPFL's Photonics Systems
Laboratory (PHOSL). "But for the last few years we've hit a sort of
ceiling, and scientists all over the world are trying to break
through."
While others have attempted to solve the problem by
altering the properties of the fibers themselves, Brès and fellow EPFL
scientist Luc Thévenaz claim to have broken through the current throughput
ceiling by focusing on the pulses of light that travel through them.
Data is transmitted through optical fibers as a
series of light pulses that form codes. Simply put, a transmitter at one end
sends an "on" pulse to signify a 1, and an "off" pulse to
signify a 0, with the pulses decoded at the receiving end of the fiber. The
limiting factor has been that there needs to be some space between the pulses
so they don't interfere with each other, ensuring the data can be reliably
decoded at the receiver.
After noticing that the changes in the shape of
the pulses could limit the interference, Brès and Thévenaz were able to
produce long-sought-after "Nyquist sinc pulses" that fit together more closely.
"These pulses have a shape that's more pointed,
making it possible to fit them together, a little bit like the pieces of a
jigsaw puzzle lock together," says Brès. "There is of course some
interference, but not at the locations where we actually read the data."
The researchers were able to generate a pulse that
is more than 99 percent perfect using a simple laser and modulator, but believe
the technology could fit on a simple chip. This, coupled with the fact that
existing optical fiber networks wouldn't need to be replaced, should make it
attractive to many in the telecommunications industry.
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