【作者】 毕慧宁；

【导师】 马晶；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2009， 硕士

【摘要】 卫星光通信是卫星通信技术中一个新的发展方向。它是指利用激光光束作为信息载体在卫星-地面站和卫星间建立光通信链路。量子密码术,更确切地说是量子密钥分配,它是最近二十年发展起来的一种新的通信技术,它利用量子特性来得到或提高通信的保密性。采用单光子通信技术的量子密码通信,是最有可能首先得到实际应用的量子通信技术。将量子密码术与卫星光通信相结合,进行卫星光通信中的量子密钥分配技术研究,是一项非常有意义的研究工作。单光子捕获技术是自由空间量子密钥分配的关键技术。对于单光子捕获,一个重要问题就是单光子捕获概率问题。本论文以卫星光通信为背景,对星地量子光通信单光子捕获概率进行研究。主要包括以下几方面:进一步建立基于厄米-高斯光束处于TEM₂₀、TEM₀₂、TEM₃₀、TEM（03）及TEM₁₁模式下的单光子捕获概率理论模型,通过数值仿真给出厄米-高斯光束处于不同模式下单光子捕获概率的大小,为最佳模式选择提供理论依据。给出时间滤波的具体物理模型,将该模型与数值仿真结果相结合,分析在进行单光子捕获时需淘汰的模式及最佳模式,以及其它各种模式的实际应用价值。另外,结合时间滤波的物理模型分析基于拉盖尔-高斯光束各模式下的单光子捕获概率。对于星地激光链路,还需要考虑大气因素对单光子捕获概率的影响。本文主要研究了大气衰减效应对单光子捕获概率的影响,对已建立的单光子捕获概率理论模型进行了修正,基于修正后的理论模型进行了相应的仿真分析,得出经大气衰减后单光子捕获概率的量级为10^-410^-6。最后对大气衰减效应对单光子捕获概率影响的补偿办法进行了探讨,并结合实际情况给出光束远场发散角、接收机天线孔径的最佳参数。更多还原

【Abstract】 Intersatellite optical communications can be considered as a new evolution of satellite communication technology. It uses laser as the carrier of information transmission to establish the optical communication links between the satellite and the ground station or satellites. Quantum cryptography, or more accurately, quantum key distribution, a new communication technology developed in last twenty years, is to obtain or improve communication secrecy by quantum characteristics. Quantum cryptography communication using the single-photon is the quantum communication technology that is most possible firstly to put into practice. The quantum key distribution technique in intersatellite optical communications, which combines the quantum cryptography and intersatellite optical communications, is extremely significative.Single-photon acquisition is the key technology of free-space quantum key distribution. Single-photon acquisition probability is very important. In this paper,based on intersatellite optical communications, single-photon acquisition probability in satellite-ground quantum optical communication is studied. As follows:This paper ulteriorly establishes theoretical model of single-photon acquisition probability based Hermite-Gaussian beams in TEM20、TEM₀₂、TEM₃₀、TEM₀₃ and TEM₁₁, and shows the probability in different modes by numerical emulation, which can be considered as the theoretic foundation to select the optimal mode. What’s more, this paper shows the physical model of time filtering, analyzes which mode is limited, which mode is optimal, and the practical value of other modes. In addition, single-photon acquisition probability based on Laguerre-Gaussian beam is analysed according to physical model of time filtering.For laser satellite-ground links, effects of atmosphere on single-photon acquisition probability also need be considered. In this paper, the effects of atmospheric attenuation on single-photon acquisition probability are studied, the single-photon acquisition probability theoretical model established is amended, the emulational analysis is carried out based revised theoretical model, and a conclusion that the order of single-photon acquisition probability after attenuation is 10^-410^-6. Finally, some compensation methods of effects of atmospheric attenuation on single-photon acquisition probability are discussed, and the optimal parameters of far-field beam divergence angle and receiver antenna aperture according to practice are shown.更多还原