Mirror image fiber infrastructure could bring faster, more reliable Internet

Researchers have developed a technique that uses mirror image fiber signals to dramatically increase the speed and reliability of data transmission across the Internet. News of the development was first reported in the magazine Nature Photonics.

The technique works like noise-canceling headphones that monitor the nearby environment with a microphone and generate the inverse signal of what they hear, preventing the noise from being audible. When the Internet signals are recombined on the receiving end, the noise that the signals gather in the fiber cancels out.

The BBC reported that paired beams can travel four times farther than a single one. The research 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 fiber, farther than even the longest transoceanic fiber link.

What limits the distance a light signal can travel go is how much power is in the beam, the BBC said. But the higher the power, the more the light actually interacts with the material of the fiber, rather than merely passing through it. That adds “noise” to the beam that limits the fidelity with which data can be transmitted.

To get ride of this noise comes the technique knows as “phase conjugation.”

Dr. Xiang Liu of Bell Laboratories in New Jersey and leader of the research team working on the project, suggested creating a pair of phase-conjugate beams, each carrying the same data. The noise that each gathers is equally a mirror image of that on the other, Liu told the BBC.

“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.

“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.”