基于材料调节的光子晶体波导宽带低色散特性研究

发布时间：2018-02-28 04:30

本文关键词： 光子晶体慢光光波导光流体光缓存　出处：《青岛大学》2017年硕士论文　论文类型：学位论文

【摘要】：通信技术的发展促使人们将目光转向了更具优势的光网络,但是目前的光网络中依然保有大量的光电转换器,网络的速度受到了很大的限制,必须替换网络中的电子部分,才能充分利用光的带宽优势。光缓存技术是实现光开关、光存储器等光器件的技术前提,利用这些器件实现的全光交换和光路由,是组成全光网络的关键技术,基于光子晶体慢光波导技术实现光缓存器的设计是目前研究的热点,其具有带宽大、体积小、可集成、室温运行等显著的优势。现阶段的研究中,设计出的慢光波导,被减慢的光速总伴随着较大的群速度色散,群速度色散的存在会引起信号波形出现畸变,无法被正确读取和识别。而使群速度色散降低的措施又会使带宽连带着降低,而且在实际应用中,还要求光子晶体光器件具备可重配置、开关控制、动态可调等功能。所以对波导慢光特性的优化和波导动态可控方面的研究具有重要的意义。本论文对光子晶体慢光波导的结构进行了设计,研究了特定结构慢光波导的禁带特性和慢光特性。研究主要包含以下内容:首先,介绍了光子晶体理论和能带、禁带等特性,分析了光子晶体的慢光原理和慢光性能参数,介绍光子晶体理论研究的几种主要方法,如平面波展开法、时域有限差分法等,最后介绍了研究中使用的数值仿真工具。第二,设计了一种六边形环散射元二维光子晶体结构,设计了一种圆形散射元二维光子晶体结构。对两种光子晶体的能带、禁带特性进行了研究。分别选取了一种结构参量和一种材料参量,通过调整参量的取值,研究光子晶体禁带位置和宽度的变化情况。研究结果可用于光子晶体光器件的开关控制和调谐功能的实现。第三,在六边形环散射元的光子晶体中引入线缺陷,设计慢光波导。对波导的慢光特性进行仿真,通过调整环内光流体折射率,确定能使慢光特性最优化的折射率值,再通过调整六边形内径和光流体环的内径,进一步优化慢光特性,最后调整第一行孔的平移距离,扩大了慢光的带宽范围,最终获得了带宽△n=92.9nm,群速度色散β2=4.86 ps2/mm的超大带宽超小色散的慢光。最后,在圆形散射元的光子晶体中引入缺陷,形成慢光波导,研究调整孔半径和孔折射率时,导模及慢光特性的变化规律。通过同时调整第一行孔的光流体折射率和第一行孔的半径,对慢光性能进行了优化。在不同的折射率和半径组合下,群折射率30到200的连续范围上,总能获得NDBP在0.320以上的高性能慢光。
[Abstract]:The development of communication technology has prompted people to turn their eyes to the more advantageous optical networks, but there are still a large number of photoelectric converters in the current optical networks. The speed of the network is greatly limited, and the electronic parts of the network must be replaced. Optical buffer technology is the technical premise of optical devices such as optical switch and optical memory, and all optical switching and optical routing realized by these devices is the key technology to form an all-optical network. The design of optical buffer based on photonic crystal slow optical waveguide technology is a hot research topic at present. It has many advantages, such as large bandwidth, small volume, integration, room temperature operation and so on. The slow speed of light is always accompanied by large group velocity dispersion, the existence of group velocity dispersion will cause the signal waveform distortion, which can not be read and recognized correctly, and the measures to reduce the group velocity dispersion will reduce the bandwidth. In practical applications, photonic crystal optical devices are also required to be reconfigurable and switch controlled. Therefore, it is of great significance to optimize the slow light characteristics of the waveguide and to study the dynamic control of the waveguide. In this paper, the structure of the photonic crystal slow optical waveguide is designed. The band gap and slow light characteristics of a special structure slow optical waveguide are studied. The main contents of the study are as follows: firstly, the theory of photonic crystal and the characteristics of band gap and band gap are introduced, and the principle of slow light and the parameters of slow light performance of photonic crystal are analyzed. This paper introduces several main methods for theoretical study of photonic crystals, such as plane wave expansion method, finite-difference time-domain method and so on. Finally, numerical simulation tools used in the study are introduced. Secondly, a hexagonal ring scattering element two-dimensional photonic crystal structure is designed. A two-dimensional photonic crystal structure with circular scattering elements is designed. The band band and band gap characteristics of two photonic crystals are studied. One structure parameter and one material parameter are selected, and the values of the parameters are adjusted. The change of gap position and width of photonic crystal is studied. The results can be used to realize the switch control and tuning function of photonic crystal optical device. Thirdly, the linear defect is introduced into the photonic crystal of hexagonal ring scattering element. The slow optical waveguide is designed. The slow light characteristic of the waveguide is simulated. By adjusting the refractive index of the optical fluid in the ring, the refractive index value that can optimize the slow light characteristic is determined, and then the inner diameter of the hexagonal and the optical fluid ring is adjusted. The slow light characteristics are further optimized, and the translation distance of the first row hole is adjusted to enlarge the bandwidth range of slow light. Finally, the bandwidth of slow light is 92.9 nm, and the group velocity dispersion 尾 2N 4.86 ps2/mm is very large bandwidth ultra-small dispersion slow light. Finally, By introducing defects into photonic crystals of circular scatterers to form slow optical waveguides, the variation of guiding modes and slow light properties of the first row of holes and the radius of the first row of holes are studied by adjusting the radius of the hole and the refractive index of the hole, by simultaneously adjusting the refractive index of the first row of the hole and the radius of the first line of the hole. The performance of slow light is optimized. Under different refractive index and radius combination, the high performance slow light with NDBP above 0.320 can be obtained in the continuous range of group refractive index from 30 to 200.
【学位授予单位】：青岛大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN252

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