Wednesday, 8 July 2015

New Research Hopes to Extend Fibre-Optic Data Transmissions

Optical fibre is currently the material of choice for manufacturing high-speed data cables used for broadband internet access and commercial networking.  As good as fibre-optic cabling is, it does have its drawbacks.  Among those drawbacks is something known as 'crosstalk'.  The crosstalk phenomenon is holding back our ability to scale up fibre-optic distances by distorting signals to the extent that receivers cannot decipher them.  However, all this may be on the verge of changing, thanks to research being carried out in the US.

Researchers from the University of California, San Diego (UCSD) claim they have figured out a way to increase the distance of fibre optic data communications, without sacrificing speed, by boosting the maximum power sent through the cable network at its origin.  This runs counter to everything we currently know about fibre-optic transmissions.

A major concern with current technology is that data signals are distorted once the amount of power being sent through a cable reaches a certain threshold.  This distortion - or crosstalk - can only be handled by limiting the power at the origin of the signal and using amplifiers and repeaters along the way.

As an example, data service providers currently extend fibre-optic distances using repeaters at strategic points in a network to boost signals incrementally without introducing distortion.  Unfortunately, this system hampers overall speed.  The UCSD researchers have apparently found a way to increase power past the established threshold without encountering the same crosstalk issues.  This offers the potential for increasing signal distance while maintaining speed and signal integrity.

The researchers explain what they did in a recently released paper, saying in part:

“Our approach removes this power limit, which in turn extends how far signals can travel in optical fibre without needing a repeater.”

How They Did It:

At the heart of the research team's experiments was the prediction of crosstalk parameters based on something the team referred to as ‘frequency combs’.  By being able to effectively predict crosstalk, the team was able to deploy receivers capable of correctly deciphering signals without any loss of data.  They were able to successfully power a signal across 12km of fibre-optic cable with no additional repeaters.

The team says they were able to predict crosstalk parameters because the phenomenon follows a known set of ‘fixed physical laws’ that researchers were able to observe and document.  Success was then a matter of manipulating data streams within those laws to produce the desired outcome.

What this means:

Expect infrastructure and network design to change rapidly if the US research proves fruitful on a large scale.  The first organisation that can harness greater fibre-optic distance and speed will be in an excellent position moving forward, as evidenced by companies such as BT and Sky.  BT is already working on a network it hopes will bring speeds of 500 Mbps to good portion of the UK in the next few years; Sky is hoping to reach 1 Gbps for its residential and commercial customers in the near future.

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