Quantum key distribution by a free-space MIMO system

Motti Gabay, Shlomi Arnon

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Quantum key distribution (QKD) systems for use in future free-space optical communication links restrict communication to a low bit rate. In this paper, increasing the QKD bit rate using a communication system that includes a multiple-input-multiple-output quantum key distribution (MQKD) is proposed. Such a system can enable a number of receivers to communicate simultaneously with a number of transmitter elements, which consequently increases the overall QKD bit rate. However, due to scattering and turbulence in the atmospheric channel, this method may introduce interference effects when a photon transmitted from one transmitter element reaches the wrong detector element in the receiver. These interference effects reduce the system bit rate and increase the quantum bit error rate. A novel mathematical model for analyzing the effect of crosstalk and interference on the MQKD system performance is derived. The results of the analysis indicate that atmospheric effects impair performance. In order to mitigate the atmospheric effect, using several wavelengths simultaneously is suggested. Criteria to define the number of wavelengths that are required to achieve a given performance are also provided.

Original languageEnglish
Pages (from-to)3114-3120
Number of pages7
JournalJournal of Lightwave Technology
Issue number8
StatePublished - 1 Aug 2006


  • Multiple-input-multiple-output (MIMO)
  • Optical wireless communication
  • Quantum key distribution (QKD)
  • Turbulence

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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