Abstract:

A long distance peer to peer quantum key distribution experimental system of polarization encoding was built based on BB84 protocol. With the help
of this experimental platform, quantum key distribution experiment with 5,10,15 km three different transmission distances was completed and the main parameters of the system  was collected in real time for data analysis. The experimental results show that with the increase of quantum fiber channel distance from sending end to receiving end, the system bit generation rate and the amount of key generated by the system would drop, the bit error rate of signal state and decoy state would increase within statistical time. The experimental results have theoretical and practical value for practical development of the longrange security quantum key distribution system.

Key words: quantum key distribution, BB84 protocol, decoy state; signal state, bit error rate