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, the research team of Professor Wei Zhang from the Department of Electronic Engineering, Tsinghua University has extended optical fiber transmission distance of chip-to-chip quantum teleportation by three orders of magnitude, over optical fibers of 12.3km. They 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. They 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, they 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.
On 9 July 2025, this work was published online in Light: Science & Applications under the title " Chip-to-chip photonic quantum teleportation over optical fibers of 12.3 km." Mr. Dongning Liu, a PhD candidate from the Department of Electronic Engineering, Tsinghua University, is the first author of the paper. Prof. Wei Zhang and Prof. Yidong Huang are the corresponding authors. It was supported by the Beijing Academy of Quantum Information Sciences, the National Natural Science Foundation of China and National Key research and development program of China.
Figure Principle and chip design of the chip-to-chip quantum teleportation.
(a) Scenario of a star-topology quantum network. (b) Functions of the photonic quantum teleportation involving the user node, relay node and central node. (c)-(e) Designs of the silicon photonic circuits for the user, relay, and central nodes, implementing the main functions required for quantum teleportation. (f) Photograph of the fabricated silicon photonic chip, which integrated all the three quantum photonic circuits.
