Optical amplifier offers record low noise, says Chalmers researchers

Researchers at Chalmers University of Technology in Sweden say they have demonstrated an extremely low noise optical amplifier that can extend signal reach by 4X. The phase-sensitive fiber-optic parametric amplifier (PSA) offers a noise figure of 1.1 dB, 3X less than that of conventional EDFAs. If the amplifier can be commercialized – and Chalmers described the technology behind the PSA as “practical” – it could significantly improve the performance of optical communications networks by lessening the amount of interference signals would encounter.

“This is the ultimate optical amplifier,” asserts Professor Peter Andrekson, who led the research group who developed the low-noise 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.”

An article published in Nature Photonics describes a demonstration of the technology. The non-degenerate PSA link consisted of a phase-insensitive parametric copier followed by a phase-sensitive amplifier that provided broadband amplification, signal modulation-format independence, and nearly 6-dB link noise-figure improvement over conventional links that leverage EDFAs, according to the article description. The group suggests the PSA’s noise level has a theoretical minimum of 0 dB.

Chalmers researchers say their next step is to focus on applications. In addition to wireline optical communications, the amplifier could have ramifications for free-space communications, laser radar, spectroscopy, and measurement.

The research was funded by the European Union as part of project PHASORS and by the Swedish Research Council (VR). Participating partners in the EU project include University of Southampton, University College Cork, University of Athens, Eblana, OFS, OneFive Photonics, and EXFO Sweden AB.