{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,6,17]],"date-time":"2025-06-17T05:28:10Z","timestamp":1750138090952},"reference-count":55,"publisher":"Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften","license":[{"start":{"date-parts":[[2024,8,8]],"date-time":"2024-08-08T00:00:00Z","timestamp":1723075200000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["quantum-journal.org"],"crossmark-restriction":false},"short-container-title":["Quantum"],"abstract":"<jats:p>Measurement-device-independent quantum key distribution (MDI-QKD) closes all the security loopholes in the detection system and is a promising solution for secret key sharing. Polarization encoding is the most common QKD encoding scheme, as it is straightforward to prepare and measure. However, implementing polarization encoding in MDI QKD imposes extra challenges, as polarization alignment must be maintained over both mutually unbiased bases and be maintained for both paths (Alice-Charlie and Bob-Charlie). Polarization alignment is usually done by interrupting the QKD process (reducing overall key generation rates) or using additional classical laser sources multiplexed with quantum channels for polarization alignment. Since low key rates and cost are the two most pressing challenges preventing wide adoption of QKD systems, using additional resources or reducing key rates runs contrary to making QKD commercially viable. Therefore, we propose and implement a novel polarization compensation scheme in the MDI-QKD system that avoids the aforementioned drawbacks by recycling part of discarded detection events. Our scheme evaluates the polarization drift in real-time based on single measurements corresponding to decoy intensities. Our fully automated experimental demonstration maintains the average polarization drift below 0.13 rad over 40 km of spooled fibre (without an insulating jacket) for at least four hours. The average quantum bit error rate is 3.8<mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi mathvariant=\"normal\">&amp;#x0025;<\/mml:mi><\/mml:math>, and we achieved an average key rate of <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mn>7.45<\/mml:mn><mml:mo>&amp;#x00D7;<\/mml:mo><mml:msup><mml:mn>10<\/mml:mn><mml:mrow class=\"MJX-TeXAtom-ORD\"><mml:mo>&amp;#x2212;<\/mml:mo><mml:mn>6<\/mml:mn><\/mml:mrow><\/mml:msup><\/mml:math> bits per pulse.<\/jats:p>","DOI":"10.22331\/q-2024-08-08-1435","type":"journal-article","created":{"date-parts":[[2024,8,8]],"date-time":"2024-08-08T14:44:32Z","timestamp":1723128272000},"page":"1435","update-policy":"http:\/\/dx.doi.org\/10.22331\/q-crossmark-policy-page","source":"Crossref","is-referenced-by-count":2,"title":["Resource-Efficient Real-Time Polarization Compensation for MDI-QKD with Rejected Data"],"prefix":"10.22331","volume":"8","author":[{"given":"Olinka","family":"Bedroya","sequence":"first","affiliation":[{"name":"Centre for Quantum Information and Quantum Control, Dept. of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada"}]},{"given":"Chenyang","family":"Li","sequence":"additional","affiliation":[{"name":"Centre for Quantum Information and Quantum Control, Dept. of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada"},{"name":"Department of Physics, University of Hong Kong, Pokfulam, Hong Kong"}]},{"given":"Wenyuan","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Hong Kong, Pokfulam, Hong Kong"}]},{"given":"Jianyong","family":"Hu","sequence":"additional","affiliation":[{"name":"Centre for Quantum Information and Quantum Control, Dept. of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada"}]},{"given":"Hoi-Kwong","family":"Lo","sequence":"additional","affiliation":[{"name":"Centre for Quantum Information and Quantum Control, Dept. of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, Canada"},{"name":"Centre for Quantum Information and Quantum Control, Dept. of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada"},{"name":"Quantum Bridge Technolgies, Inc., (QBT), 100 College St, Toronto, ON M5G 1L5, Canada."}]},{"given":"Li","family":"Qian","sequence":"additional","affiliation":[{"name":"Centre for Quantum Information and Quantum Control, Dept. of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, M5S 3G4, Canada"}]}],"member":"9598","published-online":{"date-parts":[[2024,8,8]]},"reference":[{"key":"0","doi-asserted-by":"publisher","unstructured":"Bennett, C. 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Lett. 76, 4656 (1996).","DOI":"10.1103\/PhysRevLett.76.4656"},{"key":"52","doi-asserted-by":"publisher","unstructured":"Curty, Marcos, et al. \"Finite-key analysis for measurement-device-independent quantum key distribution.\" Nat. Commun. 5.1 (2014): 3732.","DOI":"10.1038\/ncomms4732"},{"key":"53","doi-asserted-by":"publisher","unstructured":"Motwani, Rajeev, and Prabhakar Raghavan. Randomized algorithms. Cambridge university press, 1995.","DOI":"10.1017\/CBO9780511814075"},{"key":"54","doi-asserted-by":"publisher","unstructured":"Bourassa, J. Eli, et al. \"Loss-tolerant quantum key distribution with mixed signal states.\" Phys. Rev. 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