Fig. 3. Observation of high-rate and secure QKD.

(A) Experimentally achievable secret key rates as a function of the channel loss for the case when the number of signals transmitted by Alice is N = 6.25 × 10¹⁰ (100-s-duration communication session). The orange solid line is the simulated secret key rate. For the simulation, we set the probabilities of sending signal, decoy, and vacuum intensities to 0.8, 0.1, and 0.1, respectively. The intrinsic error rate in the time and phase basis is set to 0.03 and 0.025, respectively. (B) Experimentally observed quantum bit error rate in temporal and phase basis signal states as a function of channel loss.