Quantum teleportation has been developed to simultaneously realize the Hertz rate and the 64-km distance through fiber channels, which is essential to real-world application of quantum network.
Quantum teleportation can transfer an unknown quantum state between distant quantum nodes, which holds great promise in enabling large-scale quantum networks. To advance the full potential of quantum teleportation, quantum states must be faithfully transferred at a high rate over long distance. Despite recent impressive advances, a high-rate quantum teleportation system across metropolitan fiber networks is extremely desired. Here, we demonstrate a quantum teleportation system which transfers quantum states carried by independent photons at a rate of 7.1 ± 0.4 Hz over 64-km-long fiber channel. An average single-photon fidelity of ≥90.6 ± 2.6% is achieved, which exceeds the maximum fidelity of 2/3 in classical regime. Our result marks an important milestone towards quantum networks and opens the door to exploring quantum entanglement based informatic applications for the future quantum internet.
A real time deterministic quantum teleportation over a single fiber channel was implemented experimentally by exploiting the generated EPR entanglement at 1550 nm. A 1342 nm laser beam was used to transfer the classical information in real time and also acted as a synchronous beam to realize the synchronization of the quantum and classical information. The dependence of the fidelity on the transmission distance of the fiber channel was studied experimentally with optimizing the transmission efficiency of the lossy channel that was established to manipulate the beam of the EPR entanglement in Alice's site. The maximum transmission distance of the deterministic quantum teleportation was 10 km with the fidelity of 0.51 ± 0.01, which is higher than the classical teleportation limit of 1/2. The work provides a feasible scheme to establish metropolitan quantum networks over fiber channels based on deterministic quantum teleportation.
Nowadays, a technological challenge is to integrate quantum key distribution (QKD) protocols in already present telecommunication fiber networks. Twin-field QKD is one of the most promising techniques on long distances, but requires stabilizing the optical length of the communication channels between parties. Adapting interferometry techniques derived from frequency metrology, we developed a solution for the simultaneous key sharing and channel length control, and we demonstrated it on a 206 km field-deployed fiber with 65 dB loss. Our method reduces the quantum-bit-error-rate contributed by channel length variations to <1%, representing an effective solution for real-world quantum communications.