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题名	铌酸锂非挥发全息优化记录及集成模块化器件的研究
作者	董前民
学位类别	博士
答辩日期	2004
授予单位	中国科学院上海光学精密机械研究所
导师	刘立人
关键词	双掺杂铌酸锂 非挥发全息记录 光分插复用器 无阻塞光开关
其他题名	Optimization of Nonvolatile Holographic Recording in LiNbO3 Crystals and Their Applications in Integrated
中文摘要	铌酸锂晶体由于具有较大的光折变效应和优良的晶体光学特性，在全息数据存储、光折变三维微结构集成和光通讯等领域有重要的应用前景。然而，实际应用受到挥发性读出的限制。Buse等人提出的双掺杂LiNbO3：Fe：Mn晶体采用双色光实现非挥发全息数据存储具有易于实现、全光性、实时实地性等优点，因而成为一种非常实用化的全光学全息固定技术。本课题组发展了综合性能最好的LiNbO3：Ce：Cu双掺杂晶体。光固定技术为在单块结构铌酸锂晶体中实现光学器件的多功能三维集成提供了必要的技术支持。本论文对双掺杂LiNbO3：Ce：Cu晶体非挥发全息记录的机理和优化等问题进行了理论和实验研究，在此基础上设计了若干光通讯关键无源器件。主要内容包括：（1）首次在描述双掺杂铌酸锂晶体非挥发全息记录的理论模型中引入若干电荷迁移的特征长度，并用来描述光激发电荷载流子扩散迁移过程和不同的光生伏特迁移过程。用双中心带输运物质波方程模拟了光栅间距对任意电荷迁移长度下LiNbO3：Ce：Cu晶体非挥发全息记录的影响，并进行了相关的实验验证。在此基础上给出了优化的非挥发全息记录结构。在实际应用中，为了获得尽可能高的非挥发折射率调制度，应考虑采用透射式全息一记录结构，并选择合适的电荷迁移长度。（2）实验研究了掺杂组分比对LiNbO3：Ce：Cu晶体非挥发全息记录性能的影响，发现Cu和Ce的掺杂组分比越大，非挥发全息记录得到的记录灵敏度和固定衍射效率就越高。样品的透射谱分析表明，掺杂组分比影响了晶体的紫外光吸收特性，掺杂组分比越大，晶体对紫外光的吸收就越强。进一步的理论模拟验证了实验结果：掺杂组分比对非挥发全息记录性能的影响是通过改变晶体的紫外光吸收特性而实现的。在实际应用中，为了得到高性能的非挥发全息记录，应该考虑选择尽可能高的掺杂组分比。（3）提出一种基于双掺杂铌酸锂晶体体全息光栅和晶体光学原理的可动态重构的光分插复用器装置，该装置包括光波分解复用器和2＼2全内反射电光开关组两个基本的功能模块。给出了两种设计方案：基于若干块分立结构单一功能集成的铌酸锂晶体的光分插复用器和单块结构铌酸锂晶体多功能集成的光分插复用器。通过控制电光开关的状态，可以动态选择需要上、下路的波长信道，并可同时上、下路任意路波长信道。该装置具有结构紧凑，控制方便、插入损耗小、抗环境干扰等优点。（4）提出一种基于双掺杂铌酸锂晶体体全息光栅和电光调制的40×40波长无阻塞光开关，由四块结构相同的铌酸锂晶体构成，每块铌酸锂晶体上集成了一个1×10解复用器模块和一个10×4电光开关矩阵模块。该装置能够把任何一个输入光信号无阻塞地传送到任何一个输出端，实现了40个波长信道的无阻塞路由交换。该装置具有结构简单，运行可靠，抗环境干扰，插入损耗低，响应速度快等优点。适于大容量、高速度全光通讯网络发展的需要。
英文摘要	Lithium niobate crystals have promising applications in fields of holographic data storage, photorefractive 3-D integration and optical communications, due to their large photorefractive effects and other superior properties of optical crystallography. However, there remains a problem of volatile readout which affects the practical applications of lithium niobate crystals. Recently, Buse et al. have proposed a new technique to realize nonvolatile holographic data storage in lithium niobate crystals doubly doped with Fe and Mn. Our group developed the doublely doped LiNbO3:Ce:Cu crystals with the best synthetical performance. This technique not only realizes a real time, in-situ and all-optical recording/fixing processing in an easy way but also provides the necessary technical supports for integrating multifunctional devices in monolithic lithium niobate. In this dissertation, the mechanism and optimization of nonvolatile holographic recording in LiNbO3:Ce:Cu crystals are theoretically and experimentally investigated. Several key passive devices in optical communications are designed based on photorefractive volume holography. (1) Several characteristic charge transport lengths were introduced into the two-center band transport model in order to describe the different charge transport processes due to diffusion and the bulk photovoltaic effect. The effects of grating spacing on nonvolatile holographic recording in LiNbO3:Ce:Cu for arbitrary charge transport lengths were theoretically simulated by means of the two-center material equations. Relevant experimental verifications were also performed and the optimized holographic recording geometry was obtained. It shows that in practical applications the transmission geometry with large grating spacing and appropriate charge transport lengths should be adopted to obtain highest possible nonvolatile refractive index modulation. (2) The effects of dopant composition ratio on nonvolatile holographic recording in LiNbO3:Ce:Cu crystals were experimentally studied. The result shows that the larger the dopant composition ratio of Cu and Ce, the higher the recording sensitivity and the fixed diffraction efficiency. The optical transmission spectrum analyses indicate that the UV light absorption characteristics are related to the dopant composition ratio: larger dopant composition ratio leads to stronger UV absorption. Theoretical analyses further verified the experimental result that the dopant composition ratio affects the performance of nonvolatile holographic recording through altering the UV absorption characteristics of the crystal. It shows that in practical applications large dopant composition ratio should be a good choice to obtain nonvolatile holographic recording with high performance. (3) A dynamically configurable OADM device was proposed based on volume holographic gratings in doubly doped lithium niobate crystals and the principles of optical crystallography. The device consists of a wavelength demultiplexer module and an array of 2×2 electro-optic switches based on the internal reflection on the surface of the crystal. Two design schemes were presented: OADM based on discrete crystals with unifunctional integration and OADM based on monolithic crystal with multifunctional integration. This device can dynamically select signal channels that need to be added or dropped and simultaneously add/drop arbitrary signal channels. The suggested OADM has superior properties of simple and compact construction, convenient manipulation, lowered insertion losses and resistance to environmental perturbation. (4) A 40×40 wavelength nonblocking switch device was proposed based on volume holographic gratings in doubly doped lithium niobate crystals and electro optic modulation. The device consists of four lithium niobate crystals of the same construction, in each of which a 1×10 wavelength demultiplexer module and a 10×4 electro-optic switch matrix module were integrated. By means of the device, any input signal can be transmitted to arbitrary output port without any blocking and therefore forty signal channels can be freely exchanged inside the device. The device has merits of the simple and compact construction, reliable operation, persistence against environment, lowered insertion losses and rapid response. Therefore, the proposed switch device is well suitable for use in large scale, high speed and all-optical communication networks.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15439]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	董前民. 铌酸锂非挥发全息优化记录及集成模块化器件的研究[D]. 中国科学院上海光学精密机械研究所. 2004.

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