Quantum key distribution over a 2 km free-space channel with a high secure key rate
This work experimentally demonstrated a free-space decoy-state BB84 Quantum Key Distribution (QKD) system over a 2 km outdoor channel at 100 MHz. By implementing an active beam-wander correction system using fast-steering mirrors and position-sensitive detectors, the secure key rate was significantly boosted from 103 kbps to 164.8 kbps under atmospheric turbulence, proving active stabilization is crucial for reliable long-distance quantum communication.