基于偏振编码的水下光量子通信的理论与实验研究

发布时间：2018-04-25 21:36

本文选题：量子密钥分配 + Mie散射　；参考：《中国海洋大学》2014年硕士论文

【摘要】：近年来，建立在量子力学原理基础上的量子信息受到了人们极大的关注。作为量子信息中最接近实用化的重要分支，量子密钥分配克服了经典密码术的安全隐患，其绝对安全性在理论上已经被证明。近年来水下无线通信技术发展迅速，水下量子通信可以为其提供绝对安全的保密通信技术，研究水下量子通信不仅对推动量子信息技术的发展有重要意义，并且在海洋、军事方面有重要的应用前景。基于以上背景，研究携带密钥信息的偏振光子在海水信道中的传输特性是十分必要的。此外研究水下量子通信的实验系统中，由于光学器件存在制作工艺上的缺陷，必然会对光子的偏振态产生影响，进而影响到量子通信的误码率，因而为了确保量子通信的绝对安全性，通过实验研究偏振器件以及水信道对光子偏振态的影响也是本论文研究水下量子通信的重要内容之一。基于以上背景，本论文进行了以下两个方面的研究：1)研究偏振光子在海水信道中的传输特性；2)研究光学器件以及水信道对偏振态的影响。理论研究中，根据Mie散射理论，以Monte Carlo方法作为主要手段，结合海水信道的光学性质和量子力学的原理，对偏振光子在海水信道中的传输过程进行了数值模拟。首先，，建立一合理的海水信道模型，研究了偏振光子的多次散射矢量传输模型，然后通过编程模拟，得出了光子在海水信道中传输接收到光子的光子数、Stokes矢量、光子坐标等数据，通过分析数据研究了光子在海水信道中的衰减情况、散射光子的退偏特性、不同天气情况下的量子误码率等。我们的研究结果表明，在最清澈的海水中理论上可实现传输距离为百米量级的水下量子密钥分配。实验工作中，我们在水下量子密钥分配实验平台的基础上研究了量子密钥分配实验系统中光学元器件对偏振光子的偏振态影响情况。实验中设计了合理的实验方案分别研究了偏振无关分束器对透射光和反射光的影响，并且研究了在水信道中传输光子的偏振态变化情况；通过单光子计数器数据获得不同偏振状态的光子数，对数据进行分析得出光学器件和水信道对光子偏振态的影响。
[Abstract]:In recent years, quantum information based on the principle of quantum mechanics has attracted great attention. As the most practical branch of quantum information, quantum key distribution overcomes the hidden dangers of classical cryptography, and its absolute security has been proved theoretically. In recent years, the underwater wireless communication technology has developed rapidly, and the underwater quantum communication can provide it with absolute security secure communication technology. The study of underwater quantum communication is not only of great significance to promote the development of quantum information technology, but also in the ocean. There are important prospects for military applications. Based on the above background, it is necessary to study the transmission characteristics of the polaron carrying key information in seawater channel. In addition, in the experimental system of underwater quantum communication, due to the defects in the fabrication process of optical devices, the polarization state of photons is bound to be affected, and the bit error rate of quantum communication is also affected. Therefore, in order to ensure the absolute security of quantum communication, the influence of polarization devices and water channel on photon polarization state is also one of the important contents of this thesis. Based on the above background, in this thesis, we study the propagation characteristics of polaron in seawater channel in the following two aspects: 1) study the influence of optical devices and water channel on the polarization state. In theoretical research, according to Mie scattering theory, the Monte Carlo method is used as the main means, combining the optical properties of seawater channel and the principle of quantum mechanics, the propagation process of polaron in seawater channel is numerically simulated. Firstly, a reasonable seawater channel model is established, and the multiple scattering vector transmission model of polaron is studied. Then, the number of photons transmitted and received in seawater channel is obtained by programming simulation. The attenuation of photons in seawater channel, the depolarization characteristics of scattered photons and the quantum bit error rate in different weather conditions are studied by analyzing the data of photon coordinates. Our results show that underwater quantum key distribution with a transmission distance of 100 meters can be theoretically realized in the clearest seawater. In the experimental work, we study the influence of optical elements on the polarization state of polaron in the quantum key distribution experimental system based on the experimental platform of underwater quantum key distribution (QKD). A reasonable experimental scheme is designed to study the effect of polarization independent beam splitter on transmitted light and reflected light, and the change of polarization state of photons transmitted in water channel is studied. The number of photons in different polarization states is obtained from single photon counter data, and the influence of optical devices and water channels on the polarization states of photons is obtained by analyzing the data.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：O413;TN918

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