铌酸锂调制器核心区域的电学特性研究及仿真

发布时间：2018-01-04 18:22

本文关键词：铌酸锂调制器核心区域的电学特性研究及仿真　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：高性能的电光调制器是光通信和光信号处理领域中十分重要的部件。电光调制的原理是电光效应,即光在波导中传播时受到了电信号的调制,它的一些性质因之发生了改变。折射率的改变就是其中之一,充分利用折射率改变量中与电场相关的线性部分,就可以实现线性电光调制。以铌酸锂晶体为主要材料的调制器,是目前调制器中的主流。本文的核心是研究铌酸锂调制器核心区域的电学特性,包括区域内的电场分布研究,电学参数的提取,以及电极-波导网络的频率响应等。本文首先介绍了铌酸锂晶体的一些物理特性。铌酸锂的各向异性决定了它的物理性质是与方向有关的,在众多物理性质中重点研究了铌酸锂的电光效应,阐述了铌酸锂晶体作为调制器主要材料的合理性。然后简述了相位调制器和马赫-曾德型强度调制器的结构,工作原理和它们的输入输出特性。紧接着探讨了调制器中发生的短期直流漂移和长期直流漂移。这两种现象都会影响调制器的正常工作,必须想办法消除或者尽量减小。通过建立合理的电学模型,从模型中找出影响直流漂移的关键参数,并提出了改善直流漂移的方法。电极间的电场影响着调制器的工作,因此电极周围的电场分布是我们非常感兴趣的地方。第四章重点研究了核心区域的电场分布,包括软件仿真的方法和基于“点匹配法”的求法。在软件仿真中提出了一种电参数的估算方法,最后从得到的电场分布的结果中得到了优化器件设计的方法。一般研究调制器的性质时,都是研究它的直流特性,对于它交流特性的研究则比较少。本文最后研究了调制器的交流特性。研究基于M-Z型强度调制器展开,观察MZM分别在直流信号和交流信号下的输出,并利用收集到的数据对调制过程中重要的参数进行拟合,得到了调制器的频率响应。从频率特性曲线中,我们又可以得到电学模型中的一些有用信息,从而在时域和频域两个角度研究了调制器的性质。通过以上的工作,提高了对调制器的设计能力,并使得对调制器的性能分析更加全面。
[Abstract]:High performance electro-optic modulator is a very important component in the field of optical communication and optical signal processing. The principle of electro-optic modulation is electro-optic effect, that is, the light is modulated by electrical signal when it propagates in waveguide. The change of refractive index is one of them, which makes full use of the linear part of the refractive index change which is related to electric field. The modulator with lithium niobate crystal as the main material is the mainstream of the modulator at present. The core of this paper is to study the electrical characteristics of the core region of the lithium niobate modulator. It includes the study of electric field distribution in the region and the extraction of electrical parameters. In this paper, some physical properties of lithium niobate crystal are introduced. The anisotropy of lithium niobate determines the direction of its physical properties. The electro-optic effect of lithium niobate is studied in many physical properties, and the rationality of lithium niobate crystal as the main material of modulator is expounded. Then, the structure of phase modulator and Mach Zende intensity modulator are briefly described. The working principle and their input and output characteristics are discussed. Then the short-term DC drift and the long term DC drift in the modulator are discussed. Both of these phenomena will affect the normal operation of the modulator. We must find a way to eliminate or minimize. By establishing a reasonable electrical model, we can find out the key parameters that affect the DC drift from the model. A method to improve DC drift is put forward. The electric field between electrodes affects the work of modulator. Therefore, the electric field distribution around the electrode is of great interest to us. Chapter 4th focuses on the electric field distribution in the core region. It includes the method of software simulation and the method based on "point matching". In the software simulation, a method of estimating electrical parameters is proposed. Finally, from the results of the electric field distribution, the method of optimizing the device design is obtained. In general, the properties of the modulator are studied by the DC characteristics of the modulator. At last, the AC characteristic of modulator is studied. Based on M-Z intensity modulator, the output of MZM in DC signal and AC signal is observed. Using the collected data to fit the important parameters in the modulation process, the frequency response of the modulator is obtained. From the frequency characteristic curve, we can get some useful information in the electrical model. Through the above work, the design ability of modulator is improved, and the performance analysis of modulator is made more comprehensive.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN761

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