Niels Bohr Institute Researchers Break Quantum Barrier with Coherent Photons for Existing Fiber Networks

Niels Bohr Institute scientists achieve a quantum internet breakthrough by sending coherent single photons through standard fiber-optic networks.

By: AXL Media

Published: May 1, 2026, 6:26 AM EDT

Source: Information for this report was sourced from EurekAlert!

A New Era for Secure Global Quantum Communication

The quest for a functional quantum internet has reached a pivotal milestone as researchers at the Niels Bohr Institute successfully bridged the gap between quantum emitters and existing telecommunications infrastructure. For years, the scientific community struggled with the fact that the most efficient quantum light sources only functioned at short wavelengths, making them incompatible with the long-distance optical fibers used in modern networks. By engineering a new type of quantum dot, the research team has managed to produce single photons that are both perfectly identical and compatible with standard fiber-optic systems. According to Leonardo Midolo, this development opens a broad range of applications that rely on the transmission of uncopyable and secure quantum information.

Overcoming the Persistent Challenge of Quantum Noise

The primary obstacle to achieving this breakthrough was the high level of noise typically associated with photons produced in the telecom band. In a quantum context, noise refers to the inability to generate a consistent stream of identical photons, which is a fundamental requirement for quantum coherence. Previous attempts to work directly at telecommunications wavelengths, starting at 1260 nm, resulted in incoherent light that was largely considered useless for practical quantum applications. However, the team in Copenhagen, collaborating with researchers in Bochum, Germany, optimized the growth of ultra-low-noise emitters to challenge this long-held technical assumption.

Synchronizing Quantum Emitters with Global Fiber Infrastructure

The newly developed quantum dots emit light at approximately 1300 nm, placing them directly within the original telecom band used by today’s internet providers. This alignment is critical because it removes the need for nonlinear frequency conversion, a complicated workaround that was previously necessary to shift quantum signals into a usable range. Marcus Albrechtsen, joint first author of the study, noted that the team utilizes advanced nanofabrication in cleanrooms to pattern these materials into photonic circuits. By probing these nanochips with lasers at low temperatures, the researchers confirmed the emission of highly coherent single photons that can navigate existing networks with minimal signal loss.