光在海上-水下自由空间信道中的纠缠性能

Entanglement Performance of Light in A Sea Surface-Underwater Free Space Channel

量子纠缠概念提出以来,纠缠传输在量子通信中得到了广泛应用。基于实际的无线光学传输链路建立了海上-水下自由空间信道模型,目的是研究纠缠态在海上-水下信道中传输的纠缠性能变化。基于该模型数值仿真了光子对经过海上-水下复杂信道传输后纠缠度的改变。仿真结果表明,大气消光效应、海面入射角、海水中叶绿素浓度等因素的加强均会导致纠缠度的恶化,大气或水下传输距离的增加同样造成纠缠度的削弱。实际应用中可选择利于通信的大气环境、海面入射角等优化通信。该研究对自由空间中量子纠缠传输有着重要意义。

Since the concept of quantum entanglement was proposed,entanglement transmission has been widely used in quantum communication.Based on the actual wireless optical transmission link,the sea surface-underwater free space channel model is established,aiming to research the performance of entanglement states in it.Based on the model,the entanglement of photon pairs through the composite channel of sea surface-underwater is simulated numerically.The simulation results show that the increase of atmospheric attenuation,the incidence angle of sea surface and the concentration of chlorophyll in seawater will lead to the deterioration of entanglement.The distance of transmission in atmosphere or underwater also results in a decrease in entanglement.In actual application,we could select the atmospheric environment and incident angle of sea surface to optimize communication.The research of this paper has momentous meaning to the transmission of quantum entanglement in free space.