Gigahertz measurement-device-independent quantum key distribution using directly modulated lasers
Lo, Y. S.
Paraïso, T. K.
Shields, A. J.
npj Quantum Information
Nature Publishing Group UK
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Woodward, R. I., Lo, Y. S., Pittaluga, M., Minder, M., Paraïso, T. K., Lucamarini, M., Yuan, Z. L., & et al. (2021). Gigahertz measurement-device-independent quantum key distribution using directly modulated lasers. npj Quantum Information, 7 (1)https://doi.org/10.1038/s41534-021-00394-2
Abstract: Measurement-device-independent quantum key distribution (MDI-QKD) is a technique for quantum-secured communication that eliminates all detector side-channels, although is currently limited by implementation complexity and low secure key rates. Here, we introduce a simple and compact MDI-QKD system design at gigahertz clock rates with enhanced resilience to laser fluctuations—thus enabling free-running semiconductor laser sources to be employed without spectral or phase feedback. This is achieved using direct laser modulation, carefully exploiting gain-switching and injection-locking laser dynamics to encode phase-modulated time-bin bits. Our design enables secure key rates that improve upon the state of the art by an order of magnitude, up to 8 bps at 54 dB channel loss and 2 kbps in the finite-size regime for 30 dB channel loss. This greatly simplified MDI-QKD system design and proof-of-principle demonstration shows that MDI-QKD is a practical, high-performance solution for future quantum communication networks.
Article, /639/766/483/481, /639/624/1075/187, article
External DOI: https://doi.org/10.1038/s41534-021-00394-2
This record's URL: https://www.repository.cam.ac.uk/handle/1810/319582