Large-alphabet encoding for higher-rate quantum key distribution

Catherine Lee, Darius Bunandar, Zheshen Zhang, Gregory R. Steinbrecher, P. Ben Dixon, Franco N.C. Wong, Jeffrey H. Shapiro, Scott A. Hamilton, Dirk Englund

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The manipulation of high-dimensional degrees of freedom provides new opportunities for more efficient quantum information processing. It has recently been shown that high-dimensional encoded states can provide significant advantages over binary quantum states in applications of quantum computation and quantum communication. In particular, high-dimensional quantum key distribution enables higher secret-key generation rates under practical limitations of detectors or light sources, as well as greater error tolerance. Here, we demonstrate high-dimensional quantum key distribution capabilities both in the laboratory and over a deployed fiber, using photons encoded in a high-dimensional alphabet to increase the secure information yield per detected photon. By adjusting the alphabet size, it is possible to mitigate the effects of receiver bottlenecks and optimize the secret-key rates for different channel losses. This work presents a strategy for achieving higher secret-key rates in receiver-limited scenarios and marks an important step toward high-dimensional quantum communication in deployed fiber networks.

Original languageEnglish (US)
Pages (from-to)17539-17549
Number of pages11
JournalOptics Express
Issue number13
StatePublished - 2019

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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