Experimental Long-Distance Decoy-State Quantum Key Distribution Based on Polarization Encoding

TLDR

The experiment employs three intensity levels (0, 0.2, 0.6) and an active polarization compensation system to mitigate mode dispersion over long‑distance fiber. The one‑way decoy‑state QKD protocol achieved 102 km polarization‑encoded transmission and 75 km with a single detector, providing unconditionally secure keys while eliminating detector‑efficiency loopholes.

Abstract

We demonstrate the decoy-state quantum key distribution (QKD) with one-way quantum communication in polarization space over 102 km. Further, we simplify the experimental setup and use only one detector to implement the one-way decoy-state QKD over 75 km, with the advantage to overcome the security loopholes due to the efficiency mismatch of detectors. Our experimental implementation can really offer the unconditionally secure final keys. We use 3 different intensities of 0, 0.2, and 0.6 for the light sources in our experiment. In order to eliminate the influences of polarization mode dispersion in the long-distance single-mode optical fiber, an automatic polarization compensation system is utilized to implement the active compensation.