Quantum teleportation is a crucial function in future quantum networks, transferring quantum states through prior-distributed entanglement. Photons, as "flying" qubits, are good carriers of quantum information to achieve long-distance quantum teleportation. The photonic quantum teleportation has been demonstrated over indoor fiber spools, metropolitan fiber cables and free space between satellite and ground. Quantum photonic circuits integrate multiple optical components onto a single chip to realize complicated quantum information functions, providing a promising way to simplify the implementation of photonic quantum teleportation. Although its feasibility has been shown in previous experiments over 10-meter optical fibers, more effort is required on enhancing performance of chip-to-chip quantum teleportation.

Recently, we have extended optical fiber transmission distance of chip-to-chip quantum teleportation by three orders of magnitude, over optical fibers of 12.3km. We designed and fabricated three quantum photonic circuits on a single silicon photonic chip, each serving specific functions: heralded single-photon generation at the user node, entangled photon pair generation and Bell state measurement (BSM) at the relay node, and projective measurement of the teleported photons at the central node. To achieve such an improvement on chip-to-chip quantum teleportation, careful designs were made on both quantum photonic circuit design and system implementation. The unbalanced Mach-Zehnder interferometers (UMZI) for time-bin encoding in these quantum photonic circuits are optimized to reduce insertion losses and suppress noise photons generated on the chip. We achieved the photonic quantum teleportation over optical fibers of 12.3km based on these quantum photonic circuits, with an average fidelity of 81%. In the experiment, we established an active feedback system in the experiment to suppress the impact of fiber length fluctuation between the circuits, achieving a stable quantum interference for the Bell state measurement in the relay node. This work shows that the technologies of silicon quantum photonic chip can significantly simplify the implementation of quantum teleportation, supporting the integration of crucial functionalities in future quantum networks.    

This work was published on Light: Science & Applications (https://doi.org/10.1038/s41377-025-01920-z) at 9 July 2025 with the title of " Chip-to-chip photonic quantum teleportation over optical fibers of 12.3 km ". Ph.D candidate Dongning Liu is thefirst author of this paper. Prof. Yidong Huang and Prof. Wei Zhang are the corresponding authors of this paper.