频率一致纠缠光源的频谱特性研究

发布时间：2018-08-24 13:02

【摘要】：时间是一个基础物理量,也是目前测量精度最高的物理量。高精度的时间不仅在基础研究领域有着重要的作用，而且在应用研究、国防和国民经济建设中都有着普遍应用。精密时间的应用离不开高精度的时间同步技术。传统的时间同步精度最终会受限于经典测量的散粒噪声极限。为了使时间同步的精度突破传统散粒噪声极限的测量精度限制，量子时间同步的基本概念被提出来。光源在理想的光子数压缩和频率一致纠缠状态下，所测量的信号脉冲传播时延的准确度将达到量子力学的海森堡极限---亚皮秒甚至飞秒量级。量子时间同步广泛使用频率纠缠源作为其时间信号的载体，因此量子纠缠源的特性直接影响到最终的同步精度。我们有必要对纠缠源的量子纠缠特性进行完整描述，，通过产生高质量的频率纠缠源并对其特性进行深入研究，是提高量子时间同步的时间传递精度的重要手段之一。本文主要对自发参量下转换过程产生的频率一致纠缠光源的量子纠缠特性进行了分析。主要的研究内容和研究成果如下： (1)搭建纠缠光源频谱测量光路，设计自动化控制系统，测量了不同泵浦带宽条件下的频谱特性，完成了对频率一致纠缠光源的量子纠缠特性的表征。根据测量结果计算了纠缠度，为进一步分析纠缠光源所具备的频率纠缠度与量子时间同步可达到的时间同步精度之间的关系做准备。 (2)将实验结果与理论计算结果进行比对与分析,两者具有良好的一致性。验证了改变泵浦光带宽对频率一致纠缠光源的量子纠缠特性的影响。 (3)构建基于光纤链路的实验演示系统，在基于HOM干涉仪的量子时间同步协议中实现了远距离传输纠缠双光子；研究了相关控制方法，并在实验中实现了HOM干涉仪两臂等长锁定，保障了后续实验研究的顺利进行。
[Abstract]:Time is not only a basic physical quantity, but also the most accurate one. High precision time plays an important role not only in the field of basic research, but also in applied research, national defense and national economic construction. The application of precision time can not be separated from high precision time synchronization technology. The traditional time synchronization accuracy will be limited by the classical measurement of the particle noise limit. In order to make the precision of time synchronization break through the limit of measurement precision of traditional shot noise limit, the basic concept of quantum time synchronization has been put forward. In the ideal state of photon number compression and frequency consistent entanglement, the accuracy of the measured signal pulse propagation delay will reach the Heisenberg limit of quantum mechanics, subpicosecond or even femtosecond. The frequency entanglement source is widely used as the carrier of the time signal in quantum time synchronization, so the characteristics of the quantum entanglement source directly affect the final synchronization accuracy. It is necessary for us to describe the quantum entanglement characteristics of entangled source completely. It is one of the important methods to improve the time transfer accuracy of quantum time synchronization by generating high quality frequency entanglement source and deeply studying its characteristics. In this paper, the quantum entanglement characteristics of the frequency consistent entanglement source generated by the spontaneous parametric downconversion process are analyzed. The main research contents and results are as follows: (1) the spectrum measurement path of entangled light source is built and an automatic control system is designed to measure the spectrum characteristics under different pump bandwidth. The quantum entanglement properties of the frequency consistent entangled light source have been characterized. Based on the measurement results, the entanglement degree is calculated. In order to further analyze the relationship between the frequency entanglement degree of entangled light source and the time synchronization accuracy that quantum time synchronization can achieve. (2) compare and analyze the experimental results with the theoretical results. There is good consistency between the two. The effects of varying the pump bandwidth on the quantum entanglement characteristics of the frequency-consistent entangled light source are verified. (3) the experimental demonstration system based on fiber link is constructed. In the quantum time synchronization protocol based on HOM interferometer, the long distance transmission of entangled two-photon is realized, the correlation control method is studied, and the equal length locking of the two arms of the HOM interferometer is realized in the experiment, which ensures the smooth progress of the subsequent experimental research.
【学位授予单位】：中国科学院研究生院（国家授时中心）
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB939

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