【作者】 杨秦岭；

【导师】 柯熙政；

【作者基本信息】 西安理工大学 ， 电路与系统， 2010， 硕士

【摘要】 近年来,对具有轨道角动量的光束研究是光通信领域的一大热点,此种光束含有相位因子exp(ilθ)。本文论述了不同大气湍流条件下,光子轨道角动量探测概率受低阶大气湍流像差的影响情况,文章在已经很成熟的光束轨道角动量编码理论的基础上,提出了一种应用单光子轨道角动量态进行编码的光通信方案。从调制子系统、解调子系统等方面阐述了其基本原理、组成结构及关键技术。本文主要工作包括：1.调制子系统的设计及其实现。对具有轨道角动量光束的产生原理及其特性进行了详细的分析,选择了计算机生成相位全息图来实现它,并对具有轨道角动量的单光子产生原理进行了简要说明。2.解调子系统的设计及其实现。包括高灵敏度的光电探测器件的选择,光束旋转器对光信号的处理部分,还对一些辅助器件略作了介绍。3.该通信系统的工作原理。从单光子轨道角动量态的产生到应用于通信编码,主要给出了公式推导,最后还对此系统的安全性和优点进行了简要说明。理论分析表明,与利用偏振态编码相比,此系统能够提高通信容量,并能提高信息密度。因此,对多组正交的单光子轨道角动量态编码的推广,是很有意义的,它可极大的提高码元生成效率,改善信息的传输速率。最后对全文提出的理论进行了总结,指出了在今后研究工作中有待于完善的问题。更多还原

【Abstract】 In recent years,the research for the beam of spiral wave-front that with phase factor exp(ilθ) is a hot topic in the field of optical communication. In this paper, provides an overview of some orbital angular momentum with the beam characteristics and corresponding the size of single-photon orbital angular momentum.Photon orbital angular momentum’s probability of detection was influenced on low level atmospheric turbulence aberration within different conditions of atmospheric turbulence, made a optical communications program that apply of single-photon orbital angular momentum states encode. The key technique, system architecture and basis principle of the equipment are demonstrated from the modulation subsystem and demodulation subsystem. This thesis carried through the following aspects of study:1. Design and implement of modulation subsystem.The principle of arising and characteristics of the beam that have the orbital angular momentum were carried out a detailed analysis, chosen the computer-generated hologram to achieve it, for a brief description that the single-photon with orbital angular momentum generated.2. Design and implement of demodulation subsystem. Including the chose of the photoelectric detector that is high sensitivity, beam rotator and composite phase grating for the part of optical signal processing. Also assisted on some devices introduced slightly.3. The working principle of communication systems. From the single-photon orbital angular momentum states have applied to the communication code, the main given is the formula for the course of their work at a glance, Finally, have a brief description for the security of this system.The oretical analysis shows that this system have a high reliability, and compared with the use of polarization encoding,this system can improve the communication capacity. Therefore, the promotion of state encoding with multiple sets of orthogonal single-photon orbital angular momentum is of great significance, it can greatly improve the efficiency of code generated and improve information transfer rate. Finally, the author put forward a summary for the theory of the full text, pointed out the question that to be perfect by the research work in the future.更多还原