{
  "abstract": "Twin-field (TF) quantum key distribution (QKD) offers a promising approach to long-distance QKD networks due to its superior performance over large channel losses. Due to specialized hardware requirements, nearly all long-distance TFQKD demonstrations have only two users exchanging keys, rather than a network with three or more users. In this work, we experimentally demonstrate a proof-of-principle three-user-pair Sagnac TFQKD network spanning 127-km using single-photon avalanche detectors without any active phase stabilization or postcompensation. We implement efficient procedures for maintaining polarization stability and circumventing Rayleigh backscattering noise to achieve a stable Sagnac interference visibility of $93\\pm1$% over one hour. A secure key rate of $1.398\\times10^{-5}$ bits per pulse is achieved over an asymmetric communication channel with 102-km fiber and 45-dB overall loss. To our knowledge, this is the first TFQKD network without active phase stabilization or postcompensation achieved over long fibers. Our results represent a highly practical and cost-effective approach to long-distance QKD networks.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.04447",
  "author_total": 5,
  "authors": [
    {
      "name": "Reem Mandil"
    },
    {
      "name": "Yen-An Shih"
    },
    {
      "name": "Abhay Verma"
    },
    {
      "name": "Li Qian"
    },
    {
      "name": "Hoi-Kwong Lo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e9khrntxz05a5.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.04447",
  "fulltext_url": null,
  "id": "e9khrntxz05a5",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.04447",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.app-ph"
    ],
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "arxiv",
      "quant-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.04447",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e9khrntxz05a5.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:26:03Z",
      "native_id": "2609.04447",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.04447"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.app-ph",
      "subfield": "applied-instrumentation"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    },
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Proof-of-principle long-distance Sagnac twin-field quantum key distribution network",
  "title_text": "Proof-of-principle long-distance Sagnac twin-field quantum key distribution network",
  "type": "preprint",
  "updated_at": "2026-10-30T12:26:03Z",
  "url": "https://research.draconitic.com/paper/e9khrntxz05a5",
  "venue": "arXiv",
  "versions": []
}