Experimental Synchronization of a Quantum Communication System

Abstract: The article considers an algorithm for detecting an optical signal pulse during the clock synchronization of a quantum key distri-bution system. Several methods for synchronizing quantum communication equipment are reviewed and it is shown that the distinctive characteristics are reduced to the values of the proba-bility of correctly detecting a signal time interval containing an optical pulse and the average time of entering synchronization. The scheme of the experimental setup is described and the re-sults of full-scale studies of the autocompensation quantum key distribution system are presented. The results show the parame-ters of the energy model of the clock synchro-nization process in the presence of destabilizing factors in the quantum channel. An experiment was conducted to introduce optical couplers with an atmospheric path into the quantum channel. The possi-bility of diverting part of the optical radiation from the commu-nication channel during clock synchronization is demonstrated, which can be used by an intruder to interfere with the operation of the quantum key distribution system. The possible data leak-age channels in the general structure of quantum cryptographic networks are described.

Keywords: trusted nodes, detec-tion probability, photon pulse, quantum key, quantum communications