Research On And Realization Of Qualntum Key Distribution

Quantum key distribution is the first commercial application of quantuminformation technology. It has attracted much attentions and got very fast developmentin the last decade. In this paper we focus on quantum key distribution in both theory andexperiments.First, we will briefly introduce the concept, background, progress and some relatedtechnologies of quantum key distribution.Secondly, an experiment system based on single SPD, polarization-encoding andB92 scheme is built. Alice sends 0? or 45? polarized quasi single photon pulserandomly. When they arrive at Bob, the pulses with different polarizations enter theSPD in different time divisions, so only one SPD is needed to detect severalpolarizations. Because of the modification of optical path and electrical circuits, theoptical attenuation is reduced and the remote synchronization is more stable. As a result,the performance of whole system is remarkably improved.Thirdly, we suggest some improvement schemes of BB84: Alice could announcethe basis partly in advance to improve the efficiency ; A modified error-test method issuggested to improve the security; A new method is suggested to simplify theerror-correction.Finally, we review the paper and give some suggestion for future works.