Low-cost high-speed internet in the offing

In an advance that may dramatically reduce cost and energy consumption of high-speed internet communication, researchers have developed an optical medium in which multiple beams of light can autocorrect their their own shapes without affecting other beams.

Nonlinear-optical effects can process data thousands of times faster than what electrically could be achieved, researchers said.

Such processing has worked only for one optical beam at a time because in the presence of multiple light beams, the nonlinear-optical effects also cause unnecessary inter-beam interaction, or crosstalk.

Researchers from University of Texas at Arlington (UTA) in the US and the University of Vermont (UVM) in Canada enabled simultaneous nonlinear-optical processing of multiple light beams by a single device without converting them to electrical form, opening the way for this technology to reach its full potential.
 

"Our new nonlinear medium has allowed us to demonstrate simultaneous all-optical regeneration of 16 wavelength- division multiplexing (WDM) channels by a single device, and this number has only been limited by the logistical constraints of our laboratory," said Michael Vasilyev, professor at UTA.

"This experiment opens the opportunities to scale the number of channels to over a hundred without increasing the cost, all in a book-sized device," said Vasilyev, who led the study published in the journal Nature Communications.

Currently to eliminate the noise accumulated during light propagation in optical communication links, telecom carriers must resort to frequent optoelectronic regeneration.

This converts optical signals to electrical via fast photo-detectors, process them with silicon-based circuitry, and then convert the electrical signals back to optical, using lasers followed by electro-optic modulators.

Each optical fiber can carry over a hundred different signals at various wavelengths, known as wavelength-division multiplexing (WDM), researchers said.

Such an opto-electronic regeneration needs to be done separately for each wavelength, making regenerators large, expensive and inefficient consumers of power, they said.