High-fidelity entangled photon pairs from a quantum-dot-based single-photon source
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2026
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| _version_ | 1866915903311970304 |
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| author | Marczak, Malwina A. Johnson, Spencer J. Hogg, Mark R. Baltisberger, Timon L. Arnold, Nathan Nussbaum, Benjamin E. Pillot, Clotilde M. N. Valentin, Sascha R. Ludwig, Arne Kwiat, Paul G. Warburton, Richard J. |
| author_facet | Marczak, Malwina A. Johnson, Spencer J. Hogg, Mark R. Baltisberger, Timon L. Arnold, Nathan Nussbaum, Benjamin E. Pillot, Clotilde M. N. Valentin, Sascha R. Ludwig, Arne Kwiat, Paul G. Warburton, Richard J. |
| contents | Entangled photon pairs are a ubiquitous resource in quantum technologies, used in quantum key distribution and quantum networking as well as fundamental tests of non-locality. For scalable quantum networks, pairs that are indistinguishable in all unentangled degrees of freedom are essential, as they enable high-fidelity entanglement swapping across network nodes. To date the most-studied sources of "swappable" entangled photon pairs have been based on spontaneous parametric down-conversion (SPDC) in non-linear crystals. However, the probabilistic nature and unavoidable trade-off between brightness and unwanted multi-photon emission limits their performance in lossy channels. Here, we demonstrate a high-fidelity source of "swappable" entangled photon pairs using a semiconductor quantum dot (QD) coupled to a tunable microcavity. By actively modulating the QD emission between orthogonal polarisation states, delaying one path in a low-loss Herriott cell, and recombining the two on a balanced beam splitter, we generate entangled photon pairs with a fidelity of $96.1\pm0.5$ %. We identify and mitigate fidelity-limiting factors, achieving a maximum fidelity of $98.1\pm0.5$ % through time-resolved post-selection. The scheme suppresses residual multi-photon events concentrated near the excitation pulse and has only a modest impact on the rate. Furthermore, the photons are mutually indistinguishable, enabling efficient entanglement swapping. Our results establish semiconductor QDs as a viable platform for quantum network-compatible swappable entangled photon pair generation, with feasible entanglement generation rates exceeding 0.5 Gpairs/s. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2603_29971 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | High-fidelity entangled photon pairs from a quantum-dot-based single-photon source Marczak, Malwina A. Johnson, Spencer J. Hogg, Mark R. Baltisberger, Timon L. Arnold, Nathan Nussbaum, Benjamin E. Pillot, Clotilde M. N. Valentin, Sascha R. Ludwig, Arne Kwiat, Paul G. Warburton, Richard J. Quantum Physics Entangled photon pairs are a ubiquitous resource in quantum technologies, used in quantum key distribution and quantum networking as well as fundamental tests of non-locality. For scalable quantum networks, pairs that are indistinguishable in all unentangled degrees of freedom are essential, as they enable high-fidelity entanglement swapping across network nodes. To date the most-studied sources of "swappable" entangled photon pairs have been based on spontaneous parametric down-conversion (SPDC) in non-linear crystals. However, the probabilistic nature and unavoidable trade-off between brightness and unwanted multi-photon emission limits their performance in lossy channels. Here, we demonstrate a high-fidelity source of "swappable" entangled photon pairs using a semiconductor quantum dot (QD) coupled to a tunable microcavity. By actively modulating the QD emission between orthogonal polarisation states, delaying one path in a low-loss Herriott cell, and recombining the two on a balanced beam splitter, we generate entangled photon pairs with a fidelity of $96.1\pm0.5$ %. We identify and mitigate fidelity-limiting factors, achieving a maximum fidelity of $98.1\pm0.5$ % through time-resolved post-selection. The scheme suppresses residual multi-photon events concentrated near the excitation pulse and has only a modest impact on the rate. Furthermore, the photons are mutually indistinguishable, enabling efficient entanglement swapping. Our results establish semiconductor QDs as a viable platform for quantum network-compatible swappable entangled photon pair generation, with feasible entanglement generation rates exceeding 0.5 Gpairs/s. |
| title | High-fidelity entangled photon pairs from a quantum-dot-based single-photon source |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2603.29971 |