Photon-efficient quantum cryptography with pulse-position modulation

Tian Zhong; Feihu Xu; Zheshen Zhang; Hongchao Zhou; Alessandro Restelli; Joshua C. Bienfang; Ligong Wang; Gregory W. Wornell; Jeffrey H. Shapiro; Franco N. C. Wong

arXiv · 1510.06126

Photon-efficient quantum cryptography with pulse-position modulation

Tian Zhong·Feihu Xu·Zheshen Zhang·Hongchao Zhou·Alessandro Restelli·Joshua C. Bienfang·Ligong Wang·Gregory W. Wornell·Jeffrey H. Shapiro·Franco N. C. Wong

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Abstract

The binary (one-bit-per-photon) encoding that most existing quantum key distribution (QKD) protocols employ puts a fundamental limit on their achievable key rates, especially under high channel loss conditions associated with long-distance fiber-optic or satellite-to-ground links. Inspired by the pulse-position-modulation (PPM) approach to photon-starved classical communications, we design and demonstrate the first PPM-QKD, whose security against collective attacks is established through continuous-variable entanglement measurements that also enable a novel decoy-state protocol performed conveniently in post processing. We achieve a throughput of 8.0 Mbit/s (2.5 Mbit/s for loss equivalent to 25 km of fiber) and secret-key capacity up to 4.0 bits per detected photon, thus demonstrating the significant enhancement afforded by high-dimensional encoding. These results point to a new avenue for realizing high-throughput satellite-based or long-haul fiber-optic quantum communications beyond their photon-reception-rate limits.

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BibTeX RIS

Tian Zhong, Feihu Xu, Zheshen Zhang, Hongchao Zhou, Alessandro Restelli, Joshua C. Bienfang, Ligong Wang, Gregory W. Wornell, Jeffrey H. Shapiro, Franco N. C. Wong. 2015-10-21. Photon-efficient quantum cryptography with pulse-position modulation. https://arxiv.org/abs/1510.06126

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