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.
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BibTeX (Download)
@unpublished{Woodward2021,
title = {Gigahertz measurement-device-independent quantum key distribution using directly modulated lasers},
author = {R. I. Woodward and Y. S. Lo and M. Pittaluga and M. Minder and T. K. Paraïso and M. Lucamarini and Z. L. Yuan and A. J. Shields},
url = {https://www.riwoodward.com/publication_files/woodward_2021_mdi.pdf},
doi = {10.1038/s41534-021-00394-2},
year = {2021},
date = {2021-04-08},
journal = {npj Quantum Information},
volume = {7},
pages = {58},
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.},
keywords = {qkd},
pubstate = {forthcoming},
tppubtype = {unpublished}
}