{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T15:18:54Z","timestamp":1773155934846,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2023,11,22]],"date-time":"2023-11-22T00:00:00Z","timestamp":1700611200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000266","name":"Engineering and Physical Sciences Research Council","doi-asserted-by":"publisher","award":["EP\/T001011\/1"],"award-info":[{"award-number":["EP\/T001011\/1"]}],"id":[{"id":"10.13039\/501100000266","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>The future quantum internet will leverage existing communication infrastructures, including deployed optical fibre networks, to enable novel applications that outperform current information technology. In this scenario, we perform a feasibility study of quantum communications over an industrial 224 km submarine optical fibre link deployed between Southport in the United Kingdom (UK) and Portrane in the Republic of Ireland (IE). With a characterisation of phase drift, polarisation stability and the arrival time of entangled photons, we demonstrate the suitability of the link to enable international UK\u2013IE quantum communications for the first time.<\/jats:p>","DOI":"10.3390\/e25121572","type":"journal-article","created":{"date-parts":[[2023,11,22]],"date-time":"2023-11-22T08:47:43Z","timestamp":1700642863000},"page":"1572","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Quantum Communications Feasibility Tests over a UK-Ireland 224 km Undersea Link"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5723-0881","authenticated-orcid":false,"given":"Ben","family":"Amies-King","sequence":"first","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5861-2574","authenticated-orcid":false,"given":"Karolina P.","family":"Schatz","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5953-5227","authenticated-orcid":false,"given":"Haofan","family":"Duan","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7500-145X","authenticated-orcid":false,"given":"Ayan","family":"Biswas","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"given":"Jack","family":"Bailey","sequence":"additional","affiliation":[{"name":"euNetworks Fiber UK Limited, 5 Churchill Place, London E14 5HU, UK"}]},{"given":"Adrian","family":"Felvinti","sequence":"additional","affiliation":[{"name":"euNetworks Fiber UK Limited, 5 Churchill Place, London E14 5HU, UK"}]},{"given":"Jaimes","family":"Winward","sequence":"additional","affiliation":[{"name":"euNetworks Fiber UK Limited, 5 Churchill Place, London E14 5HU, UK"}]},{"given":"Mike","family":"Dixon","sequence":"additional","affiliation":[{"name":"euNetworks Fiber UK Limited, 5 Churchill Place, London E14 5HU, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5922-9529","authenticated-orcid":false,"given":"Mariella","family":"Minder","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"},{"name":"Department of Electrical Engineering, Computer Engineering and Informatics, Cyprus University of Technology, Limassol 3036, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6813-6401","authenticated-orcid":false,"given":"Rupesh","family":"Kumar","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8324-4358","authenticated-orcid":false,"given":"Sophie","family":"Albosh","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7351-4622","authenticated-orcid":false,"given":"Marco","family":"Lucamarini","sequence":"additional","affiliation":[{"name":"School of Physics, Engineering & Technology and York Centre for Quantum Technologies, Institute for Safe Autonomy, University of York, York YO10 5FT, UK"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.tcs.2014.05.025","article-title":"Quantum cryptography: Public key distribution and coin tossing","volume":"560","author":"Bennett","year":"2014","journal-title":"Theor. Comp. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1103\/RevModPhys.74.145","article-title":"Quantum cryptography","volume":"74","author":"Gisin","year":"2002","journal-title":"Rev. Mod. Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"025002","DOI":"10.1103\/RevModPhys.92.025002","article-title":"Secure quantum key distribution with realistic devices","volume":"92","author":"Xu","year":"2020","journal-title":"Rev. Mod. Phys."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1012","DOI":"10.1364\/AOP.361502","article-title":"Advances in quantum cryptography","volume":"12","author":"Pirandola","year":"2020","journal-title":"Adv. Opt. Photonics"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/BF00191318","article-title":"Experimental quantum cryptography","volume":"5","author":"Bennett","year":"1992","journal-title":"J. Cryptol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3121","DOI":"10.1103\/PhysRevLett.68.3121","article-title":"Quantum cryptography using any two nonorthogonal states","volume":"68","author":"Bennett","year":"1992","journal-title":"Phys. Rev. Lett."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2398","DOI":"10.1364\/OL.44.002398","article-title":"All-fiber self-compensating polarization encoder for quantum key distribution","volume":"44","author":"Agnesi","year":"2019","journal-title":"Opt. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"4706","DOI":"10.1364\/OL.396412","article-title":"Stable, low-error, and calibration-free polarization encoder for free-space quantum communication","volume":"45","author":"Avesani","year":"2020","journal-title":"Opt. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"220801","DOI":"10.1103\/PhysRevLett.130.220801","article-title":"Fully Passive Quantum Key Distribution","volume":"130","author":"Wang","year":"2023","journal-title":"Phys. Rev. Lett."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1038\/s41586-018-0066-6","article-title":"Overcoming the rate-distance limit of quantum key distribution without quantum repeaters","volume":"557","author":"Lucamarini","year":"2018","journal-title":"Nature"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1038\/s41566-019-0377-7","article-title":"Experimental quantum key distribution beyond the repeaterless secret key capacity","volume":"13","author":"Minder","year":"2019","journal-title":"Nat. Photonics"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"530","DOI":"10.1038\/s41566-021-00811-0","article-title":"600-km repeater-like quantum communications with dual-band stabilization","volume":"15","author":"Pittaluga","year":"2021","journal-title":"Nat. Photonics"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1038\/s41566-021-00928-2","article-title":"Twin-field quantum key distribution over 830-km fibre","volume":"16","author":"Wang","year":"2022","journal-title":"Nat. Photonics"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"210801","DOI":"10.1103\/PhysRevLett.130.210801","article-title":"Experimental Twin-Field Quantum Key Distribution over 1000 km Fiber Distance","volume":"130","author":"Liu","year":"2023","journal-title":"Phys. Rev. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"15043","DOI":"10.1038\/ncomms15043","article-title":"Fundamental Limits of Repeaterless Quantum Communications","volume":"8","author":"Pirandola","year":"2017","journal-title":"Nat. Commun."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1103\/PhysRevLett.67.661","article-title":"Quantum cryptography based on Bell\u2019s theorem","volume":"67","author":"Ekert","year":"1991","journal-title":"Phys. Rev. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1103\/PhysRevLett.68.557","article-title":"Quantum cryptography without Bell\u2019s theorem","volume":"68","author":"Bennett","year":"1992","journal-title":"Phys. Rev. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1895","DOI":"10.1103\/PhysRevLett.70.1895","article-title":"Teleporting an unknown quantum state via dual classical and Einstein\u2013Podolsky-Rosen channels","volume":"70","author":"Bennett","year":"1993","journal-title":"Phys. Rev. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1038\/37539","article-title":"Experimental quantum teleportation","volume":"390","author":"Bouwmeester","year":"1997","journal-title":"Nature"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1121","DOI":"10.1103\/PhysRevLett.80.1121","article-title":"Experimental Realization of Teleporting an Unknown Pure Quantum State via Dual Classical and Einstein\u2013Podolsky-Rosen Channels","volume":"80","author":"Boschi","year":"1998","journal-title":"Phys. Rev. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"075001","DOI":"10.1088\/1367-2630\/11\/7\/075001","article-title":"The SECOQC quantum key distribution network in Vienna","volume":"11","author":"Peev","year":"2009","journal-title":"New J. Phys."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"10387","DOI":"10.1364\/OE.19.010387","article-title":"Field test of quantum key distribution in the Tokyo QKD Network","volume":"19","author":"Sasaki","year":"2011","journal-title":"Opt. Express"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1038\/s41534-019-0221-4","article-title":"Cambridge quantum network","volume":"5","author":"Dynes","year":"2019","journal-title":"NPJ Quantum Inf."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"eaba0959","DOI":"10.1126\/sciadv.aba0959","article-title":"A trusted node\u2013free eight-user metropolitan quantum communication network","volume":"6","author":"Joshi","year":"2020","journal-title":"Sci. Adv."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2848","DOI":"10.1364\/OL.422890","article-title":"Resource-effective quantum key distribution: A field trial in Padua city center","volume":"46","author":"Avesani","year":"2021","journal-title":"Opt. Lett."},{"key":"ref_26","unstructured":"Glick, M., Srivastava, A.K., and Akasaka, Y. (2021). Metro and Data Center Optical Networks and Short-Reach Links IV, SPIE."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2200061","DOI":"10.1002\/qute.202200061","article-title":"Deploying an Inter-European Quantum Network","volume":"6","author":"Ribezzo","year":"2023","journal-title":"Adv. Quantum Technol."},{"key":"ref_28","unstructured":"Bersin, E., Grein, M., Sutula, M., Murphy, R., Huan, Y.Q., Stevens, M., Suleymanzade, A., Lee, C., Riedinger, R., and Starling, D.J. (2023). Development of a Boston-area 50-Km Fiber Quantum Network Testbed. arXiv."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"6134","DOI":"10.1038\/s41467-022-33919-0","article-title":"Continuous entanglement distribution over a transnational 248-km fiber link","volume":"13","author":"Neumann","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"6684","DOI":"10.1073\/pnas.1818752116","article-title":"Entanglement distribution over a 96-km-long submarine optical fiber","volume":"116","author":"Wengerowsky","year":"2019","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1038\/s41534-019-0238-8","article-title":"Passively stable distribution of polarisation entanglement over 192 km of deployed optical fibre","volume":"6","author":"Wengerowsky","year":"2020","journal-title":"NPJ Quantum Inf."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Ribezzo, D., Zahidy, M., Lemmi, G., Petitjean, A., De Lazzari, C., Vagniluca, I., Conca, E., Tosi, A., Occhipinti, T., and Oxenl\u00f8we, L.K. (2023). Quantum Key Distribution over 100 Km Underwater Optical Fiber Assisted by a Fast-Gated Single-Photon Detector. arXiv.","DOI":"10.1103\/PhysRevApplied.20.044052"},{"key":"ref_33","unstructured":"(2023, September 25). euNetworks. Available online: https:\/\/eunetworks.com\/."},{"key":"ref_34","unstructured":"Clivati, C., Marra, G., Levi, F., Mura, A., Xuereb, A., and Calonico, D. (2020). Proceedings of the Conference on Lasers and Electro-Optics (2020), Optica Publishing Group. Paper SM2N.1."},{"key":"ref_35","unstructured":"(2023, September 25). Polarization Entangled Photon Sources|OZ Optics Ltd. Available online: https:\/\/www.ozoptics.com\/products\/polarization-entangled-photon-sources.html."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1364\/OPTICA.4.000163","article-title":"Long-distance quantum key distribution secure against coherent attacks","volume":"4","author":"Lucamarini","year":"2017","journal-title":"Optica"},{"key":"ref_37","unstructured":"(2023, September 25). ID281 Superconducting Nanowire Series|IDQuantique. Available online: https:\/\/www.idquantique.com\/quantum-sensing\/products\/id281-snspd-series\/."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"057901","DOI":"10.1103\/PhysRevLett.91.057901","article-title":"Quantum key distribution with high loss: Toward global secure communication","volume":"91","author":"Hwang","year":"2003","journal-title":"Phys. Rev. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"230503","DOI":"10.1103\/PhysRevLett.94.230503","article-title":"Beating the Photon-Number-Splitting Attack in Practical Quantum Cryptography","volume":"94","author":"Wang","year":"2005","journal-title":"Phys. Rev. Lett."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"230504","DOI":"10.1103\/PhysRevLett.94.230504","article-title":"Decoy State Quantum Key Distribution","volume":"94","author":"Lo","year":"2005","journal-title":"Phys. Rev. Lett."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"17369","DOI":"10.1364\/OE.27.017369","article-title":"Auto-balancing and robust interferometer designs for polarization entangled photon sources","volume":"27","author":"Horn","year":"2019","journal-title":"Opt. Express"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"250802","DOI":"10.1103\/PhysRevLett.130.250802","article-title":"Twin-Field Quantum Key Distribution without Phase Locking","volume":"130","author":"Li","year":"2023","journal-title":"Phys. Rev. Lett."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1038\/s41467-021-27808-1","article-title":"Coherent phase transfer for real-world twin-field quantum key distribution","volume":"13","author":"Clivati","year":"2022","journal-title":"Nat. Commun."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"012326","DOI":"10.1103\/PhysRevA.72.012326","article-title":"Practical decoy state for quantum key distribution","volume":"72","author":"Ma","year":"2005","journal-title":"Phys. Rev. A"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"23241","DOI":"10.1364\/OE.21.023241","article-title":"Entanglement distribution over 300 km of fiber","volume":"21","author":"Inagaki","year":"2013","journal-title":"Opt. Express"}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/12\/1572\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:27:09Z","timestamp":1760131629000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/12\/1572"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,11,22]]},"references-count":45,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2023,12]]}},"alternative-id":["e25121572"],"URL":"https:\/\/doi.org\/10.3390\/e25121572","relation":{},"ISSN":["1099-4300"],"issn-type":[{"value":"1099-4300","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,11,22]]}}}