{
  "abstract": "Practical deployment of entanglement-based quantum key distribution (QKD) networks requires photon sources that simultaneously address fiber transmission loss, detector performance, and system cost–constraints that are individually well-understood but collectively unresolved in current source designs. Here we present a detector-optimized, wavelength-hybrid entangled photon source (EPS) that resolves this trilemma by design and show its performance in a QKD system. The source uses type-0 spontaneous parametric down-conversion in a crossed-crystal periodically poled KTiOPO $$_4$$ (ppKTP) configuration pumped at 473 nm, generating polarization-entangled photon pairs at 680 nm and 1550 nm. This highly nondegenerate wavelength combination is engineered to route the 680 nm photon to a high-efficiency, low-cost Si-SPAD detector while transmitting the 1550 nm photon through standard telecom fiber with minimum attenuation. The source achieves a spectral brightness of (1.9 × 10 ³ )s ⁻¹ mW ⁻¹ GHz ⁻¹ pairs over a 300 GHz phase-matching bandwidth, with polarization entanglement visibilities of (97.3 ± 1.0)% and (94.9 ± 1.6)% in the H/V and D/A bases, corresponding to a state fidelity of $$\\ge $$ (96.1 ± 1.3)%. These results establish the wavelength-hybrid approach as a scalable and cost-effective building block for deployed entanglement-based QKD nodes and future quantum network infrastructure.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "name": "Vasile-Laurenţiu Dosan"
    },
    {
      "name": "Alek Lagarrigue"
    },
    {
      "name": "Alessandro Zannotti"
    },
    {
      "name": "Tushar Parab"
    },
    {
      "name": "Yannick Folwill"
    },
    {
      "name": "Fabian Steinlechner"
    },
    {
      "name": "Oliver de Vries"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1c0ynnd72jncb.bib",
  "cited_by": 0,
  "doi": "10.1038/s41598-026-78321-8",
  "fulltext_url": "https://doi.org/10.1038/s41598-026-78321-8",
  "id": "1c0ynnd72jncb",
  "issns": [
    "2045-2322"
  ],
  "landing_url": "https://www.nature.com/articles/s41598-026-78321-8",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0",
  "metadata_licence": null,
  "native_subjects": [
    [
      "lcc",
      "Q"
    ],
    [
      "lcc",
      "R"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.nature.com/articles/s41598-026-78321-8.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": "Springer Science and Business Media LLC",
  "ris": "https://research.draconitic.com/paper/1c0ynnd72jncb.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T00:20:51Z",
      "native_id": "10.1038/s41598-026-78321-8",
      "source": "crossref",
      "url": "https://www.nature.com/articles/s41598-026-78321-8"
    },
    {
      "first_seen": "2026-11-08T14:20:57Z",
      "native_id": "06cfe53626eb4c59a0a25c01ebefc45a",
      "source": "doaj",
      "url": "https://doi.org/10.1038/s41598-026-78321-8"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "lcc:R",
      "subfield": "general"
    }
  ],
  "title": "Detector-optimized wavelength-hybrid entangled photon source for scalable fiber quantum key distribution",
  "title_text": "Detector-optimized wavelength-hybrid entangled photon source for scalable fiber quantum key distribution",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T14:21:17Z",
  "url": "https://research.draconitic.com/paper/1c0ynnd72jncb",
  "venue": "Scientific Reports",
  "versions": []
}