【作者】 师瑞娟；

【导师】 陈南；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2008， 硕士

【摘要】 自从1984年Bennet和Brassard联合提出了国际上第一个量子密钥分发方案BB84协议以来,世界各国都围绕着如何实现更加高效和安全的量子密钥分发方案做出了一系列的研究。本文针对量子通信系统网络的构建做出了相关的研究。本文在讨论量子比特性质的基础上,将传统的量子密钥分发协议与纠缠光子对的纠缠特性相结合,讨论了一种改进的BB84协议——基于纠缠的BB84协议。为了考察该协议的可行性,利用量子计算语言分别针对协议的正确性和安全性进行了仿真验证,并进一步考察衰落信道对协议工作的影响。仿真结果表明,基于纠缠的BB84协议也是绝对安全可靠、切实可行的量子密钥分发协议。为了满足实际构建量子通信网络的需要,设计实现了一种利用激光二极管制备准单光子源的方案,重点实现了激光二极管驱动电路和高速窄脉冲生成电路的设计。高速窄脉冲生成电路的生成脉冲的脉宽可以达到纳秒级,从而保证了激励产生的脉冲激光持续时间极短;而脉冲激光输出功率的稳定可由驱动电路保证。因此,在经过选取一定的衰减器对输出脉冲激光进行衰减之后可以得到良好的准单光子源,为以后的量子通信系统的搭建提供了基础。更多还原

【Abstract】 Since Bennet and Brassard united to bring forward the first quantum key distribution BB84 protocol in 1984, a series of study on how to realize the more effective and more secure quantum key distribution has been done in many countries. The work on building the quantum communication system network is done in the paper.The traditional quantum key distribution protocol was combined with the entanglement of the entangled photon pairs, and an improved BB84 protocol, the entangled photon pairs-based BB84 protocol, was discussed, after the qubit specialty is discussed. In order to examine feasibility of the improved protocol, we simulated its validity and security, using the quantum computation language (QCL).And the affect of channel attenuation to the protocol was taken into account. The result of the simulation shows that: entangled photon pairs-based BB84 protocol is an utterly secure and feasible quantum key distribution protocol.In order to fill the need in building the quantum communication network, an approximate-single-photon source preparation project which used the laser-diode is designed. The laser-diode drive circuit and the high-speed narrow pulses generation are chiefly implemented. The pulse width generated can achieve the ns level, so that the duration of the pulse-laser is terribly short. And the output power of the pulse-laser is stable by the driver circuit. Therefore, after the definite attenuation, the pulse-laser output would be a well approximate-single-photon source. It affords a base to build the quantum communication system next.更多还原