【摘要】 在自由空间量子密钥分配中,单光子源采用具有泊松分布的高度衰减激光脉冲,量子密码术协议采用BB84和B92协议。通过引入量子信道传输率、单光子捕获概率、测量因子和数据筛选因子,建立了量子误码率理论模型,给出了量子误码率的表达式。对于自由空间量子信道,引起量子误码率的主要因素是光学元件、探测器暗噪声和空间光学环境,并对这些因素进行了分析。针对低轨卫星_地面站间链路,进行了量子误码率的数值仿真研究。结果表明,在低轨卫星_地面站间进行量子密钥分配是可行的,限制自由空间量子密钥分配链路距离的主要因素是探测器暗噪声和空间光学环境。更多还原

【Abstract】 Highly attenuated laser pulses with Poisson distribution are used as single-photon sources and the BB84 and B92 protocols are used for free-space quantum key distribution.By introducing the quantum channel transmission,the single-photon acquisition probability,the measuring factor and the sifting factor,the theoretical model of the quantum bit error rate was established and the expressions of the quantum bit error rate were given.The main factors that cause the quantum bit error rate are the optical elements,the detector dark noise and the space optical environment and these factors were analyzed.The quantum bit error rate was analyzed in the numerical simulation for the laser links between a ground station and a satellite in a low earth orbit.The results show that it is feasible to implement quantum key distribution between a ground station and a satellite in a low earth orbit and that it is the detector dark noise and the space optical environment that limit the link distance for free-space quantum key distribution.更多还原