Full-Photonic Quantum Teleportation Achieved at Telecom Wavelengths

18 Nov 2025 – In a breakthrough for quantum communication, a research team led by Tim Strobel has demonstrated quantum teleportation between two remote quantum dot systems at standard fiber-optic (1550 nm) telecommunications wavelengthsquantumzeitgeist.com. The experiment, published in Nature Communications on Nov 17, is the first full-photonic quantum teleportation using distinct solid-state photon sources. In simpler terms, the researchers transferred the quantum state of a photon from one quantum dot to another, without the two ever directly interacting, by leveraging entanglement and a Bell-state measurement.

Why is this significant? Quantum teleportation is a fundamental building block for quantum networks and a future “quantum internet.” It allows quantum information (qubits) to be sent between distant nodes instantly (in practice, via previously shared entanglement and classical communication) without the qubit traveling through the intervening space. Teleportation has been done before in various forms, but usually between photons from the same source or in lab setups not compatible with real-world telecom infrastructure. Here, telecom-wavelength photons from two different semiconductor quantum dots – essentially tiny “artificial atoms” on chips – were made to interfere and achieve teleportation with high fidelity. This bridges a big gap between quantum communication research and practical deployment over today’s fiber networks.

How they did it: The team used two remote indium gallium arsenide (GaAs) quantum dots as photon emitters. One quantum dot was tuned to emit pairs of entangled photons (signal and idler), while the other quantum dot emitted single photons whose quantum state (polarization) would be teleported. Because the two quantum dot sources naturally emit at slightly different wavelengths, the researchers employed polarization-preserving quantum frequency converters to shift the photons into the same telecom band (1550 nm) without losing their quantum coherence.

They then performed a Bell-state measurement on an entangled photon from the first source and the single photon from the second source when those two photons arrived at a beamsplitter. A successful joint measurement (detecting a specific two-photon interference pattern) projects the distant single photon’s state onto the remaining partner photon of the entangled pair, completing the teleportation. Thanks to the frequency conversion, the two photons could interfere despite coming from different sources.

The results: The team reported an interference visibility of ~30% at telecom wavelengths between photons from the separate quantum dots – a sign that quantum interference was achieved despite the independent sources (visibility >0 indicates two-photon indistinguishability). More importantly, the teleportation fidelity (a measure of how faithfully the quantum state was transferred) reached about 0.72 (72%) in a post-selected subset of trials. This is well above the 2/3 (66.7%) theoretical “classical” limit (the maximum fidelity achievable by any strategy without entanglement). Surpassing that threshold confirms genuine quantum teleportation was achieved, not just a trivial copying.

While 72% fidelity, with post-selection, indicates there’s room for improvement (a perfect teleportation would yield fidelity 1.0), this is a major proof-of-principle. It demonstrates that solid-state quantum node devices (quantum dots) can be entangled and used for quantum teleportation in the same band used by existing fiber optics. In the past, experiments often used bulk optics or atoms at visible wavelengths; here it’s semiconductor chips at infrared fiber wavelengths, which is much more practical for scaling up quantum networks.

Why it matters for the future: A global quantum internet will require sources of entangled photons, quantum memory nodes, and the ability to reliably teleport states over long distances (since direct transmission of qubits is lossy over distance). By showing that distinct chip-based sources can teleport qubits to each other over telecom fiber (in principle, the experiment could be extended with fiber spools or real distance), this work paves the way for modular quantum networks. One can imagine quantum dot-based repeaters or nodes in different cities generating entanglement and teleporting quantum information across a fiber backbone. Because the photons are at 1550 nm, they can travel long distances in standard fiber with minimal loss, especially if augmented by emerging quantum repeater technology.

The use of semiconductor quantum dots is also notable because they are a promising platform for quantum hardware: they can be manufactured with techniques similar to classical semiconductor chips, potentially allowing mass production of quantum light sources. Each quantum dot can emit single photons on demand and, as shown here, entangled photon pairs as well, all in a device the size of a transistor.

In summary, this is the first time anyone has teleported a qubit between light emitted by two separate solid-state devices at telecom wavelength. It’s a key step toward real-world quantum communications that interface smoothly with today’s telecom infrastructure. The community is excited because it brings quantum repeaters and long-distance secure quantum communication (like quantum key distribution networks) closer to reality. As one more bridge between lab results and deployable tech, it underscores that the quantum internet vision – connecting quantum processors and sensors across the globe – is steadily materializing.