Decoy-state quantum key distribution with practical light source

The performance of active decoy-state quantum key distribution (QKD) system with a practical light source is compared with that of passive decoy-state QKD. The effect of statistical fluctuation due to a finite data size on final secret key rate is analyzed. This procedure is based on the standard error analysis on the assumption that all the variables measured in the experiment fluctuate around their asymptotic values. The relation between key generation rate and secure transmission distance is shown with exchanged quantum efficiency of threshold detector ( η d =1 and η d =0.4) under the condition of active decoy-state (or passive decoy-state ) QKD which we pick the data size to be N =6.0×10 9 . This analysis will provide important parameters for practical QKD experiment.