{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:02:41Z","timestamp":1760058161390,"version":"build-2065373602"},"reference-count":31,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,3,14]],"date-time":"2025-03-14T00:00:00Z","timestamp":1741910400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["2023.01100.BD.","GA 101017733","GA 101091730"],"award-info":[{"award-number":["2023.01100.BD.","GA 101017733","GA 101091730"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"EU QuantERA program","award":["2023.01100.BD.","GA 101017733","GA 101091730"],"award-info":[{"award-number":["2023.01100.BD.","GA 101017733","GA 101091730"]}]},{"name":"EU DIGITAL-2021-QCI-01 Programme","award":["2023.01100.BD.","GA 101017733","GA 101091730"],"award-info":[{"award-number":["2023.01100.BD.","GA 101017733","GA 101091730"]}]},{"name":"project PTQCI","award":["2023.01100.BD.","GA 101017733","GA 101091730"],"award-info":[{"award-number":["2023.01100.BD.","GA 101017733","GA 101091730"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Photonics"],"abstract":"<jats:p>We present a framework to optimize the voltage range of electro-optic polarization controllers (EPC) in polarization-based quantum key distribution (QKD) subsystems. In this study, we consider an EPC capable of modifying both the phase difference between its fast and slow axes and the orientation of the fast axis. This capability allows it to transform any input state of polarization (SOP) into any desired output SOP on the Poincar\u00e9 sphere using a single wave-plate. When multiple wave-plates are available, properly distributing the required polarization modulation across them effectively reduces the electronic demands, lowers the implementation costs, and enhances the polarization modulation speeds. This optimization is achieved through the application of multi-objective optimization (MOO) and wave-plate splitting techniques. Within a simulation model, using the calibration parameters from a commercially available six-wave-plate EPC, we determined the optimized voltage ranges required to achieve the six, four, and three SOPs typically used in polarization-based QKD protocols. Two voltage reference points are considered in our study: bias voltage points, which result in zero birefringence, and zero voltage points. For optimization procedures centered around the bias voltage points, we observe a significant reduction in the voltage range, from \u00b137 V, for a single wave-plate, to approximately \u00b16 V, for six wave-plates. Furthermore, using wave-plate splitting techniques, we conclude that only two independent wave-plates (four variables) need to be considered in our model to achieve optimized results, which contributes to the efficient design of polarization-based QKD subsystems by minimizing voltage transitions while ensuring precise SOP control, ultimately enabling cost-effective and high-speed polarization modulation.<\/jats:p>","DOI":"10.3390\/photonics12030267","type":"journal-article","created":{"date-parts":[[2025,3,14]],"date-time":"2025-03-14T08:46:46Z","timestamp":1741942006000},"page":"267","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Optimization of Voltage Requirements in Electro-Optic Polarization Controllers for High-Speed QKD Systems"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9815-5582","authenticated-orcid":false,"given":"Hugo Filipe","family":"Costa","sequence":"first","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"},{"name":"Department of Electronics, Telecommunications and Informatics, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2101-5896","authenticated-orcid":false,"given":"Armando Nolasco","family":"Pinto","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"},{"name":"Department of Electronics, Telecommunications and Informatics, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4412-8025","authenticated-orcid":false,"given":"Nelson Jesus","family":"Muga","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"},{"name":"Department of Electronics, Telecommunications and Informatics, University of Aveiro, Campus Universit\u00e1rio de Santiago, 3810-193 Aveiro, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1109\/MSEC.2022.3141918","article-title":"The State of the Art in Integer Factoring and Breaking Public-Key Cryptography","volume":"20","author":"Boudot","year":"2022","journal-title":"IEEE Secur. 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