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The Analysis of Intensity Correlation in Laser Transceiving Systems for Formation of a Cryptographic Key


The potentials for and limitations to the use of intensity fluctuations of laser beams propagating through a turbulent atmosphere for generating random data when keying in confidential optical communication systems are analyzed. The technique is based on the reciprocity theorem for optical fields. Light propagation in a system of two transceivers directed at each other, the signals from which are distorted by an atmospheric channel, is numerically simulated. An experimental setup is created; the generation of random correlated signals in this system is experimentally studied. A need for low-pass filtration of signals received is experimentally ascertained. The efficiency of this filtration is estimated. The dependences of the correlation coefficient on the geometrical parameters of the system and turbulent conditions along the propagation path are derived from the numerical simulation in a wide range of distances, aperture radii, and turbulence strength values. Theoretical results are shown to be in a good agreement with the results of laboratory experiments.

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The work was financially supported by the Russian Science Foundation in the part of theoretical and experimental studies of the possibilities of using the reciprocity principle for optical communication lines in a turbulent medium (project no. 18-19-00437) and by the Russian Foundation for Basic Research in the part of the study of statistics of beam energy parameters (project no. 18-29-20 115\18). The numerical simulation techniques and algorithms for laser beam propagation in the atmosphere were developed within program of fundamental research of the Russian Academy of Sciences no. AAAA-A17-117021310143-2.

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Correspondence to V. P. Aksenov, V. V. Dudorov or V. V. Kolosov.

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The authors declare that they have no conflicts of interest.

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Translated by O. Ponomareva

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Aksenov, V.P., Dudorov, V.V., Kolosov, V.V. et al. The Analysis of Intensity Correlation in Laser Transceiving Systems for Formation of a Cryptographic Key. Atmos Ocean Opt 33, 571–577 (2020).

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  • laser radiation
  • confidential optical communication
  • cryptography
  • atmospheric turbulence
  • intensity fluctuations
  • reciprocity theorem