Impact of Optical Connectors on QKD Transmission

ABSTRACTThis paper describes the effect of different optical connector polishing techniques on the quantum channel of a quantum key distribution (QKD) Clavis3 system. First, the basic differences among these types of connector polishing are briefly described. Second, the paper focuses on the design of a simple optical route to measure the effect of APC/UPC (angled physical contact/ultra physical contact) connectors on the quantum channel functionality, which is attributed to the slightly different characteristics of the two types of connectors. However, both types of connectors are commonly employed in real networks. For this reason, two series of measurements are made, one measurement for APC connectors and one measurement for UPC connectors. In each series, the number of connectors is gradually increased by up to 12 connectors per route for a given type. Finally, the results of the measurements, which mainly comprise changes in the three main parameters, are presented. In particular, the key rate, interferometric visibility and QBER (quantum bit error rate) were monitored.KEYWORDS: APC/UPC connectorsAttenuationCOWIDQKey rateQBERQKDReflectionand visibility Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by the Ministry of the interior of the Czech Republic.Notes on contributorsO. KlíčníkOndrej Klicnik was born in Brno (Czech Republic), in 1998. Currently he is a doctoral student in the field of Information Security at the Faculty of Electrical Engineering and Communication at Brno University of Technology. In his bachelor and master thesis he was conducting research in the field of security of optical networks, especially quantum key distribution.P. MünsterPetr Munster was born in 1984, in Zlin (Czech Republic). He received his PhD at the Brno University of Technology, Department of Telecommunications in 2014 on the thesis entitled Parameters of the FTTx networks. His current research themes focus on fiber-optic sensors, especially distributed fiber-optic sensors, and on fiber-optic telecommunications. He has had approximately 50 scientific publications in journals and conferences in the last 5 years.T. HorváthTomas Horvath was born in Havirov, Czech Republic in 1989. He is a young researcher at Brno University of Technology and a researcher at CESNET. He received his PhD degree in communications and informatics from Brno University of Technology in 2017. His record shows more than 40 peer reviewed proceedings and journal papers. His current research interests include optical networking, passive optical networks, and sensing.