Modular Quantum Key Distribution Setup for Research and Development Applications

Quantum key distribution (QKD), ensuring the unconditional security of information, attracts a significant deal of interest. An important task is to design QKD systems as a platform for education as well as for research and development applications and fast prototyping new QKD protocols. Here, we present a modular QKD setup driven by National Instruments (NI) cards with open source LabView code, open source Python code for post-processing procedures, and open source protocol for external applications. An important feature of the apparatus developed is its flexibility offering the possibility to modify optical schemes, as well as prototype, and verify novel QKD protocols. The other distinctive feature of the setup developed is the implementation of the decoy-state protocol, which is a standard tool for secure long-distance quantum communications. By testing the plug-and-play scheme realizing BB84 and decoy-state BB84 QKD protocols, we show that the developed QKD setup shows a high degree of robustness beyond laboratory conditions. We demonstrate the results of the use of the developed modular setup for QKD experiments in the urban environment.