Nature Nanotechnology (2026). DOI: 10.1038/s41565-026-02156-7"> Telecom QDs in a gated photonic crystal waveguide. Credit: Nature Nanotechnology (2026). DOI: 10.1038/s41565-026-02156-7

Researchers at the Niels Bohr Institute have broken a longstanding barrier by managing to send single photons—that can't be copied or split and thus are secure—in the network of optical fibers we already have. This opens up a broad range of applications relying on secure quantum information. The research is published in the journal Nature Nanotechnology .

Signal loss in optical fibers

Quantum dots are unsurpassed in their ability to generate coherent single photons—single particles of light which cannot be split or copied and therefore are secure for quantum communication. So far, the problem was that the best quantum dots only worked around 930 nm wavelengths, which is far short of the telecommunication-compatible wavelengths starting at 1260 nm.…