Research project to crack the code of quantum light sources and quantum networks

Quantum technology enables unbreakable encryption and entirely new types of computers, which can solve problems that today’s computers cannot handle. Even the biggest supercomputers must give up when it comes to detailed calculations of, e.g., chemical reactions.

There is now a race between different platforms for quantum technologies, and one of the most promising is photonics, which stores quantum information in states of light in optical quantum networks. Unfortunately, a central building block is missing, namely a new type of quantum light source, which does not exist today. A new research and innovation project aims to change that.

The technological vision is based on combining nanophotonic chips from DTU with unique technologies in materials, nanoelectromechanics, nanolithography, and quantum systems.

"It is a really difficult task, but we have also set a really strong team. One of the toughest goals is to integrate quantum light sources with quantum memories. This seemed unrealistic just a few years ago, but now we see a path forward," says Søren Stobbe, professor at DTU.

There are many different types of quantum light sources today, but either they do not work with quantum memories or they are incompatible with optical fibers.

There is actually only one viable option: the element erbium. However, erbium interacts too weakly with light. The interaction needs to be significantly enhanced, and this is now possible thanks to new nanophotonic technology developed at DTU.

The project requires not only advanced nanophotonics but also quantum technology, integrated pho-tonics with extremely low power consumption, and new nanofabrication methods—all of which hold great potential. To take just one example, the same photonic chips that the project will develop for quantum technologies are also of direct relevance for data centers, where more photonic chips are used.

The researchers will combine DTU’s expertise in nanophotonics with erbium technology from Helmholtz-Zentrum Dresden-Rossendorf, quantum networks from Humboldt University in Berlin, nanotechnology from Beamfox Technologies ApS, and integrated photonics from Lizard Photonics ApS.