{
  "abstract": "Free-space quantum key distribution (QKD) provides crucial advantages, including mobility and deployment exibility, for securing next-generation communication networks. However, atmospheric turbulence and beam wander severely degrade single-photon coupling effciency and link stability over outdoor channels. In this work, we experimentally demonstrate a free-space decoy-state BB84 QKD system operating at 803 nm with a 100 MHz repetition rate over a 2 km outdoor link. By employing an active beam-wander correction based on fast-steering mirrors (FSMs) and position sensitive detectors (PSDs) with a 500 Hz control loop, we enhance the ?ber coupling effciency and achieve an average ?nite-key secure key rate of 110 kbps with an average quantum bit error rate (QBER) of 3.28 %, representing a 2.5 times secure key rate enhancement under an active beam stabilization. This work demonstrates the indispensability of active beam stabilization and provides an operational reference for robust, long-range free-space quantum communication.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.24118",
  "author_total": 7,
  "authors": [
    {
      "name": "Kyungdeuk Park"
    },
    {
      "name": "Dongkyu Kim"
    },
    {
      "name": "Dong-Gil Im"
    },
    {
      "name": "Yonggi Jo"
    },
    {
      "name": "Jisu Kim"
    },
    {
      "name": "Jonguk Choi"
    },
    {
      "name": "Yong Sup Ihn"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c2knvc37n524d.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.24118",
  "fulltext_url": null,
  "id": "c2knvc37n524d",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.24118",
  "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",
      "quant-ph"
    ],
    [
      "openalex",
      "1702|Quantum Information and Cryptography"
    ]
  ],
  "openalex": "W7171485468",
  "pdf_url": "https://arxiv.org/pdf/2607.24118",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c2knvc37n524d.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:32Z",
      "native_id": "2607.24118",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.24118"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Quantum key distribution over a 2 km free-space channel with a high secure key rate",
  "title_text": "Quantum key distribution over a 2 km free-space channel with a high secure key rate",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:28Z",
  "url": "https://research.draconitic.com/paper/c2knvc37n524d",
  "venue": "arXiv",
  "versions": []
}