High-dimensional quantum key distribution (HD-QKD) allows two parties to generate multiple secure bits of information per detected photon. In this work, we show that decoy state protocols can be practically implemented for HD-QKD using only one or two decoy states. HD-QKD with two decoy states, under realistic experimental constraints, can generate multiple secure bits per coincidence at distances over 200 km and at rates similar to those achieved by a protocol with infinite decoy states. Furthermore, HD-QKD with only one decoy state is practical at short distances, where it is almost as secure as a protocol with two decoy states. HD-QKD with only one or two decoy states can therefore be implemented to optimize the rate of secure quantum communications.
@article{arxiv.1411.1070,
title = {Practical high-dimensional quantum key distribution with decoy states},
author = {Darius Bunandar and Zheshen Zhang and Jeffrey H. Shapiro and Dirk R. Englund},
journal= {arXiv preprint arXiv:1411.1070},
year = {2015}
}