Atmospheric effects on continuous-variable quantum key distribution

Compared to fiber continuous-variable quantum key distribution (CVQKD), atmospheric link offers the possibility of a broader geographical coverage and more flexible transmission. However, there are many negative features of the atmospheric channel that will reduce the achievable secret key rate, suc...

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Bibliographic Details
Published in:New journal of physics 2018-08, Vol.20 (8), p.83037
Main Authors: Wang, Shiyu, Huang, Peng, Wang, Tao, Zeng, Guihua
Format: Article
Language:English
Subjects:
Atmospheric effects
Boundary layers
Continuous fibers
continuous variable
Performance degradation
Physics
Quantum cryptography
quantum key distribution
secret key rate
Transmittance
Turbulence effects
Variation
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Summary:Compared to fiber continuous-variable quantum key distribution (CVQKD), atmospheric link offers the possibility of a broader geographical coverage and more flexible transmission. However, there are many negative features of the atmospheric channel that will reduce the achievable secret key rate, such as beam extinction and a variety of turbulence effects. Here we show how these factors affect performance of CVQKD, by considering our newly derived key rate formulas for fading channels, which involves detection imperfections, thus form a transmission model for CVQKD. This model can help evaluate the feasibility of experiment scheme in practical applications. We found that performance deterioration of horizontal link within the boundary layer is primarily caused by transmittance fluctuations (including beam wandering, broadening, deformation, and scintillation), while transmittance change due to pulse broadening under weak turbulence is negligible. Besides, we also found that communication interruptions can also cause a perceptible key rate reduction when the transmission distance is longer, while phase excess noise due to arrival time fluctuations requires new compensation techniques to reduce it to a negligible level. Furthermore, it is found that performing homodyne detection enables longer transmission distances, whereas heterodyne allows higher achievable key rate over short distances.
ISSN:1367-2630
1367-2630
DOI:10.1088/1367-2630/aad9c4