Newswise – Researchers at Chalmers University of Technology, Sweden, present a unique optical amplifier that is expected to revolutionize both space communication and fiber communication. The new amplifier offers high performance, is compact enough to fit into a chip of just a few millimeters and, above all, does not generate excess noise.

“It could be compared to switching from an old dial-up Internet to modern broadband, with high speed and quality,” says Professor Peter Andrekson, director of the photonics laboratory. at the Department of Microtechnology and Nanosciences at Chalmers.

Optical communication allows information to be sent over very long distances. The technology is useful in a range of applications, such as space communications and fiber optic cables for Internet traffic.

With communication based on light, rather than radio waves, we could, for example, quickly send high-resolution images from Mars. The information, carried by laser beams, could be sent at high speed from a transmitter on the planet to a receiver on Earth or on the Moon. Optical communication also allows us to use the Internet around the world, whether the signal is transferred through fiber-optic cables under the seabed or transmitted wirelessly.

Because light – carrying information between two distant points – loses power along the way, a large number of optical amplifiers are needed. Without amplifiers, up to 99% of a fiber optic cable’s signal would disappear within 100 kilometers.

A constant struggle against excessive noise

A well-known problem in optical communication, however, is that these amplifiers add excessive noise which drastically impairs the quality of the signal you wish to send or receive. Today, Chalmers researchers present a hugely promising solution to a barrier that has existed for decades.

“We have developed the world’s first optical amplifier that dramatically improves the range, sensitivity and performance of optical communication, does not generate excessive noise – and is also compact enough to be useful in practice,” says Ping. Zhao, postdoctoral fellow at the Chalmers Photonics Laboratory and one of the principal authors of the scientific article, now published in Science Advances.

The amplification of light in the project is based on a principle known as the Kerr effect, which so far is the only known approach that amplifies light without causing significant excess noise. The principle has already been demonstrated, but never in such a compact format – previous versions were too large to be useful.

The new amplifier fits into a small chip only a few millimeters in size, compared to previous amplifiers which were several thousand times larger.

Tiny, quiet and with high performance

In addition, the new amplifiers offer a sufficiently high level of performance that they can be placed more sparingly, making them a more cost effective option. They also operate in continuous wave (CW) mode rather than pulsed only mode.

“What we are demonstrating here represents the first CW operation with extremely low noise in a compact integrated chip. This provides a realistic opportunity for practical use in a variety of applications. As it is possible to integrate the amplifier in very small modules, you can get cheaper solutions with much better performance, which makes it very interesting for long-term commercial players ”, explains Peter Andrekson, Head of the research.

The new results also open the door to entirely new technological and scientific applications, explains Peter Andrekson.

“This amplifier displays unprecedented performance. We consider this to be an important step towards practical use, not only in communication, but in areas such as quantum computers, various sensor systems and in metrology when making atmospheric measurements from satellites for monitoring the Earth.

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Learn more about the research:

• The scientific article “Overcoming the quantum limit of optical amplification in monolithic waveguides” was published in Scientists progress. The study was conducted by Zhichao Ye, Ping Zhao, Krishna Twayana, Magnus Karlsson, Victor Torres-Company and Peter Andrekson. The researchers work in the Department of Microtechnology and Nanoscience at Chalmers University of Technology.
• Chalmers researchers present the first compact monolithic CW pumped parametric amplifier and further demonstrated noise performance well below the conventional quantum limit. The results were made possible by the lowest loss ever achieved in a platform of dispersion-designed integrated waveguide silicon nitride material.
• The research project was funded by the Swedish Research Council (Grant VR-2015-00535 and VR-2020-00453), the Knut and Alice Wallenberg Foundation and Horizon 2020 Marie SkÅ‚odowska-Curie Innovative Training Network Microcomb (GA 812818) .
• Read more: Find the previous press release from Peter Andrekson’s research group.