### Abstract

We explore the use of a switchable single-photon detector (SPD) array scheme to reduce the effect of a detector's deadtime for a multi-bit/photon quantum link. The case of data encoding using M possible orbital-angular-momentum (OAM) states is specifically studied in this paper. Our method uses N SPDs with a controllable M×N optical switch and we use a Monte Carlo-based method to simulate the quantum detection process. The simulation results show that with the use of the switchable SPD array, the detection system can allow a higher incident photon rate than what might otherwise be limited by detectors’ deadtime. For the case of M=4, N=20, a 50-ns deadtime for the individual SPDs, an average photon number per pulse of 0.1, and under the limit that at most 10 % of the photon-containing pulses are missed, the switchable SPD array will allow an incident photon rate of 2250 million counts/s (Mcts/s). This is 25 times the 90 Mcts/s incident photon rate that a non-switchable, 4-SPD array will allow. The increase in incident photon rate is more than the 5 times increase, which is the simple increase in the number of SPDs and the number of OAM encoding states (e.g., N∕M=20∕4).

Original language | English (US) |
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Pages (from-to) | 132-137 |

Number of pages | 6 |

Journal | Optics Communications |

Volume | 441 |

DOIs | |

State | Published - Jun 15 2019 |

Externally published | Yes |

### Keywords

- Orbital angular momentum
- Quantum communication
- Single photon detection

### ASJC Scopus subject areas

- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering

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## Cite this

*Optics Communications*,

*441*, 132-137. https://doi.org/10.1016/j.optcom.2019.01.081