Researchers at Chalmers University of Technology, Gothenburg, Sweden, have demonstrated an optical amplifier which can amplify light with extremely low noise. The breakthrough enables a reach increase for optical fibre signals from e.g. 1000 km to 4000 km, paving way for increasing the capacity of data communications. The new amplifier could lead to better internet traffic and laser radar technology, and promote any applications where detection of very weak levels of light is essential, such as free-space communication.
Today’s flow of information demands increasing capacity. Optical amplifiers are crucial enablers of data communication, with the mission to increase data signals without first converting them to electrical signals. Not only the speed and capacity require improvements, but it has become increasingly important to maintain a high signal-to-noise ratio of the signal being transmitted.
The researchers at Chalmers University of Technology have, by using a so-called phase-sensitive fibre-optic parametric amplifier, PSA, reduced the noise figure to 1 dB. In traditional erbium-doped fibre amplifiers the noise figure is 3 dB at best, resulting in loss of signal integrity. 1 dB is the lowest noise ever reported in any kind of amplifier with reasonably large signal gain. This represents a breakthrough also because it is implemented in a practical way, making it potentially very attractive in various applications — most notably in high capacity optical communication systems.
“This is the ultimate optical amplifier. 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. In addition, the amplifier is compatible with any modulation format, with traditional laser transmitters and can be very broadband, making it compatible with many lasers at different wavelengths,” says Peter Andrekson, who has developed the low-noise amplifier together with his research group in fibre optics.
The research work at Chalmers University of Technology is funded by the European project PHASORS and the Swedish Research Council (VR). Participating partners in the EU project include University of Southampton, University College Cork, University of Athens, Eblana, OFS, One-Five Photonics and EXFO Sweden AB.