Optical amplifier could quadruple the range of fiber optic signals
By Ben Coxworth
June 23, 2011
As the amount of information being electronically shuttled around the planet continues to grow, so does the need for effective means of relaying it. The use of optical fibers has definitely helped in that regard, although thanks to a recent breakthrough at Sweden's Chalmers University of Technology, optical fiber signals may soon be able to travel four times farther than they are presently able to. Researchers there have created an optical amplifier, capable of amplifying light while maintaining a relatively noise-free signal.
There is currently not a lot in the way of details available as to how the amplifier works, although it is said to take advantage of "the fact that the refractive index of glass is not constant, but dependent on light intensity in the fiber." The abstract for a paper on the research goes on to state that the setup consists of "a phase-insensitive parametric copier followed by a phase-sensitive amplifier."
Whatever the case, it is said to dramatically boost the strength of optical fiber signals, potentially allowing a signal that could previously travel about 1,000 kilometers to now travel 4,000. Unlike previous erbium-doped fiber amplifiers, which created a signal with at least 3 decibels-worth of accompanying noise, the new amplifier only creates around 1 dB, which could theoretically be reduced to zero.
"This is the ultimate optical amplifier," said Chalmers' Prof. Peter Andrekson. "It enables connecting cities, countries and continents more efficiently by placing the amplification hubs at much greater intervals. The signal can also be modulated more effectively ... The entire optical telecom industry is our market. But the technology is generic, and scalable to other wavelengths like visible or infrared light, which makes it attractive in areas such as measurements, spectroscopy, laser radar technology and any applications where detection of very weak levels of light is essential."
The paper, "Towards ultrasensitive optical links enabled by low-noise phase-sensitive amplifiers," was recently published in the journal Nature Photonics.