| Free space quantum communication has attracted wide attention in military and daily life because of its unconditional safety.At present,because of the limitation of the propagation path,the optical fiber quantum communication system is difficult to make further breakthroughs and progress.In order to realize the communication of the far distance,the free space quantum communication system becomes the inevitable choice to complete the construction of the ultra long distance quantum communication network.In the process of free space channel transmission,light quantum is inevitably disturbed by regional conditions and external environment,and with the continuous development of the society,environmental pollution is becoming more and more serious,and the intensity of atmospheric turbulence is also enhanced,causing great interference to the transmission of message pulses.The paper mainly studies the interference of different intensity atmospheric turbulence to the transmission of message pulse in the satellite earth link quantum channel.Firstly,this paper briefly introduces the background and significance of the topic,the historical process and development of free space quantum channel.Secondly,this paper introduces the theoretical basis of the support of this article.The main contents include the qubit and its main features,the key technologies of the satellite-ground link quantum communication system.Thirdly,under the background of atmospheric turbulence with different intensities,a transmission scheme of satellite ground link with single photon pulse is proposed.Based on this scheme,a single photon efficiency model for single photon transmission in a satellite-ground link quantum channel is proposed.The interference caused by the atmospheric turbulence of different intensity on the receiver single photon receiving efficiency is derived and simulated.Then the key technical support of single photon transmission in a free space quantum channel is introduced,and the influence of the receiving aperture and transmission distance on the single photon capture rate is analyzed.Fourth,based on the QKD transmission protocol without common reference frames,a quantum error rate calculation model adapted to this scheme was proposed,and the influence of the final key generation rate on the butt end of the atmospheric turbulence was analyzed in detail.Combined with the previous single photon receiving efficiency model,we analyzed the influence of atmospheric turbulence with different intensities on the single photon counting at the receiving end.Based on the utilization rate model of channel link in classical communication,the link utilization rate model of free space quantum channel is proposed.The influence of temperature,wind speed and relative humidity on the utilization rate of quantum channel link in atmospheric environment is analyzed.The results are analyzed and the results are discussed.In this paper,we determine the message transfer between the ground launch station and the satellite receiver by analyzing the single photon counting and the final key generation rate of the receiver.Finally,the full text is summarized and prospected,so as to provide reference for completing the construction of ultra long distance quantum communication network. |
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