New Optical Medium Could Make Internet Thousand Times Faster: Study

The world is clinging onto every word of the net neutrality debate. The United States government chose to repeal net neutrality laws and this will give companies power to provide higher speeds to internet content they like and slowing down content they don’t. This move hasn’t been perceived as positive by most.

Amid this battle to “save the internet,” breakthrough research from the University of Texas at Arlington and the University of Vermont could cause a dramatic reduction in the cost and energy consumption of high-speed internet connections, making it much more accessible, cheap and super-fast.

According to the team, using nonlinear-optical effects, such as intensity-dependent refractive index, data can be transmitted and processed thousands of times faster than we know it now. Electronic means of data transfer and processing are chunky and have to counter a lot of resistance compared to optical data transfer.

So far, the only limitation for this technology has been that optical beams can only be operated one at a time because the nonlinear-optical effects also cause unwanted inter-beam interaction, or crosstalk, when multiple light beams are present.

According to a press release on the University of Texas, Arlington website, “Currently, to eliminate the noise accumulated during light propagation in optical communication links, telecom carriers must resort to frequent optoelectronic regeneration, where they convert optical signals to electrical via fast photodetectors, process them with silicon-based circuitry, and then convert the electrical signals back to optical, using lasers followed by electro-optic modulators. Since each optical fiber can carry over a hundred different signals at various wavelengths, known as wavelength-division multiplexing (WDM), such an optoelectronic regeneration needs to be done separately for each wavelength, making regenerators large, expensive and inefficient consumers of power.”

Now the team designed a method where this signal can be processed directly, without converting it to electrical and back.

The speed of light propagating in a medium can be manipulated by changing the intensity of the light source. In a transparent medium, this is a manifestation of a nonlinear-optical effect known as "self-phase modulation" or SPM.

If the light contains both signal and noise, the SPM will help filter the signal from noise by helping scatter only the sound energy into regions outside the signal band. Here, a filter is placed to remove the noise altogether.

This is known as "all-optical regeneration," which can result in optical auto-correction of the signals several times faster than conventional methods.

Till now all-optical regeneration could not be used with WDM because of frequent clashes between signals. But now, the team demonstrated a group-delay-managed nonlinear-optical medium, where strong SPM effect is achieved without such inter-channel interference.

By creating channels or splits in the optical fiber and introducing periodic-group-delay, filters helped give the team maximum yields in a medium where all frequency components of the same WDM channel travel with the same speed, ensuring strong SPM.

"Our new nonlinear medium has allowed us to demonstrate simultaneous all-optical regeneration of 16 WDM channels by a single device, and this number has only been limited by the logistical constraints of our laboratory," Vasilyev said in the report. "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."

The study was published in journal Nature Communication on Oct. 12 .