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arXiv · 2511.16350

On-chip Time-bin to Path Qubit Encoding Converter via Thin Film Lithium Niobate Photonics Chip

Xiaosong Ren·Zhanping Jin·Xiaotong Zou·Xiaole Zhang·Xue Feng·Fang Liu·Kaiyu Cui·Yidong Huang·Wei Zhang
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Abstract

The development of quantum internet demands on-chip quantum processor nodes and interconnection between the nodes. Path-encoded photonic qubits are suitable for on-chip quantum information processors, while time-bin encoded ones are good at long-distance communication. It is necessary to develop an on-chip converter between the two encodings to satisfy the needs of the quantum internet. In this work, a quantum photonic circuit is proposed to convert time-bin-encoded photonic qubits to path-encoded ones via a thin-film lithium niobate high-speed optical switch and low-loss matched optical delay lines. The performance of the encoding converter is demonstrated by the experiment of time-bin to path encoding conversion on the fabricated sample chip. The converted path qubits have an average fidelity higher than 97%. The potential of the encoding converter on applications in quantum networks is demonstrated by the experiments of entanglement distribution and quantum key distribution. The results show that the on-chip encoding converter can serve as a foundational component in the future quantum internet, bridging the gap between quantum information transmission and on-chip processing based on photons.

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Xiaosong Ren, Zhanping Jin, Xiaotong Zou, Xiaole Zhang, Xue Feng, Fang Liu, Kaiyu Cui, Yidong Huang, Wei Zhang. 2025-11-20. On-chip Time-bin to Path Qubit Encoding Converter via Thin Film Lithium Niobate Photonics Chip. https://arxiv.org/abs/2511.16350

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