Unmanned Aerial Vehicles (UAVs) are used in numerous applications ranging from environmental monitoring, disaster recovery, aerial photography, delivering consumer packages, defense, and law enforcement. Securing wireless communication between drones in-flight is critical to ensure safe operation during flight and avoid multiple types of attacks, e.g., eavesdropping, spoofing, jamming, etc. Quantum key distribution (QKD) systems provide a method for two users to exchange a provably secure key for cryptography. Here, we present progress towards demonstrating a prepare-and-measure BB84 polarization-based decoy state QKD between two drones in flight. A significant challenge includes achieving system performance under compact size, weight, and power constraints of the drone vehicle. We introduce and evaluate critical subsystems including the QKD source, which is based on three separate resonant-cavity light emitting diodes) controlled by a field-programmable gate array (FPGA). We additionally discuss the methods for achieving a 93.6% indistinguishably between the sources. The pointing, acquisition and tracking system is comprised of several cascading subsystems, which provide course alignment based on Infrared beacons/cameras with gimbals, and fine alignment using fast steering mirrors and a position-sensitive detectors. We discuss both transmit and receive optics including custom designed optical benches. Finally, we introduce single-photon detectors, FPGA-based time-tagger, and a novel statistical post-processing synchronization algorithm. Establishing a quantum communications link between drones in-flight is an important prerequisite for future drone-based quantum applications such as entanglement distribution, distributed quantum sensing, and quantum positional verification.

This is joint work with Roderick D. Cochran (Co-Author) and Daniel J. Gauthier (Principal Investigator) at The Ohio State University (OSU). This is joint work with Andrew Corad, Samantha Isaac, Timur Javid, and Paul Kwiat (Principal Investigator) at the University of Illinois at Urbana-Champaign (UIUC)