Prospects of time-bin quantum key distribution in turbulent free-space channels

Alfonso Tello Castillo, Catarina Novo, Ross Donaldson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Quantum key distribution is a quantum communication protocol which seeks to address potential vulnerabilities in data transmission and storage. One of the main challenges in the field is achieving high rates of secret key in lossy and turbulent free-space channels. In this scenario, most experimental demonstrations have used the polarization of photons as their qubit carriers, due to the relative robustness of polarization in free-space propagation. Time-bin or phase-based protocols are considered less practical due to the wave-front distortion caused by atmospheric turbulence. However, demonstrations of novel free-space interferometer designs are enabling interferometers to measure multimodal signals with high visibility. That means it is now viable to consider the prospects of implementing time-bin or phase-based protocols, which have demonstrated high key rates and long transmission distances in optical fiber. In this work, we present the possibilities of implementing time-bin protocols in turbulent free-space channels, using the coherent one-way protocol as the example. We present an analysis of the secret key rate and quantum bit error rate of the system, providing the errors due to noise counts, and the extinction ratio of the pulses. Finally, we developed a model to quantify the expected losses for a turbulence free-space channel, specifically for a free-space satellite-to-ground station channel.
Original languageEnglish
Title of host publicationEmerging Imaging and Sensing Technologies for Security and Defence V; and Advanced Manufacturing Technologies for Micro- and Nanosystems in Security and Defence III
ISBN (Electronic)9781510638945
ISBN (Print)9781510638938
Publication statusPublished - 20 Sept 2020
EventSPIE Security + Defence 2020 - Digital
Duration: 21 Sept 202025 Sept 2020

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE Security + Defence 2020
Internet address


  • Atmospheric turbulence
  • Free-space quantum key distribution
  • Quantum communication
  • Quantum technology
  • Singlephoton detection
  • Time-bin QKD

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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