混合等离子体波导结构中光传播和场局域特性研究

发布时间：2018-01-05 17:02

本文关键词：混合等离子体波导结构中光传播和场局域特性研究　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：纳米光波导是实现超高集成化光子器件的重要组成部分。目前已经提出了多种类型的纳米光波导结构,主要分为:介质波导、光子晶体波导和表面等离子体波导。此外在纳米光波导中引入缺陷可以构成光学微腔结构。光学微腔在研究光与物质的相互作用,纳米激光器等领域有着极其重要的应用,同时也是集成光路中的一类基本光学组件。现阶段提出的光学微腔存在结构复杂、尺寸较大、难以制备、模体积大等问题。针对上述问题,本文基于绝缘层上硅(Silicon-On-Insulator,SOI)平台,设计了一种具有较小模体积、高品质因子且便于制备的混合表面等离子体波导(hybrid plasmonic waveguide,简称HP波导),并对其进行了尺寸优化及传感特性的研究。本文结合了传输矩阵法和麦克斯韦方程组,推导出了一维HP波导结构中混合模式的色散关系。采用有限元法(Finite Element Method,FEM)分析了光场在波导中的模场分布及传播长度随结构尺寸、材料的介电常数等参数的变化关系,为下一步设计基于周期性混合波导的微腔结构奠定了基础。基于以上述研究得出的变化关系,本文通过在周期性HP波导中引入结构缺陷来产生缺陷态。本文利用COMSOL Multiphysics软件建立了相应的二维模型,分析了二维周期性HP波导微腔结构中光场的传播及局域特性。为了使缺陷态模式具有最小的模体积,优化了波导的几何结构并确定了模体积最小时波导的最佳宽度。本文进一步建立了三维周期性HP波导微腔结构,研究了波导中缺陷的尺寸,材料及周期数目等对混合模式传输特性的影响。利用混合表面等离子波导能够将光场限制在深亚波长尺度同时还具有低损耗的特性,通过结构优化设计出了有效模体积为0.005?m3,珀塞尔因子为3750的波导微腔。数值研究了介质层折射率的变化及在缺陷位置加入微小金属条后波导的传输特性,结果表明基于HP波导结构的纳米微腔不仅具有很高珀塞尔因子而且具备良好的传感特性。本文的研究结果为基于表面等离子体的波导元器件的优化设计提供了理论依据,对实现表面等离子体波在超高集成光路中的应用具有指导作用。
[Abstract]:Nano-optical waveguide is an important part of the realization of ultra-integrated photonic devices. At present, a variety of nano-optical waveguide structures have been proposed, mainly divided into: dielectric waveguide. Photonic crystal waveguides and surface plasma waveguides. In addition, defects can be introduced into nanoscale optical waveguides to form optical microcavities, which are studying the interaction between light and matter. Nanocrystalline lasers and other fields have very important applications, and they are also a kind of basic optical components in integrated optical path. At present, the proposed optical microcavity has complex structure, large size and difficult to be prepared. In view of the above problems, based on the Silicon-On-Insulator SOI platform on the insulation layer, a small mold volume is designed. Hybrid plasmonic waveguides (HP waveguides) with high quality factor and easy to fabricate. The dimension optimization and sensing characteristics are studied. The transmission matrix method and Maxwell equations are combined in this paper. The dispersion relation of mixed modes in one-dimensional HP waveguide structure is derived. Finite Element Method is used to solve the problem. The dependence of mode field distribution and propagation length on structure size, dielectric constant and other parameters are analyzed by FEMs. It lays a foundation for the next step to design the microcavity structure based on periodic mixed waveguide, based on the change relation obtained from the above research. In this paper, the defect states are generated by introducing structural defects into periodic HP waveguides, and the corresponding two-dimensional model is established by using COMSOL Multiphysics software. The propagation and local characteristics of the light field in a two-dimensional periodic HP waveguide microcavity structure are analyzed in order to minimize the mode volume of the defect state mode. The geometrical structure of the waveguide is optimized and the optimum width of the waveguide is determined when the mode volume is minimum. In this paper, the three-dimensional periodic HP waveguide microcavity structure is further established, and the size of the defects in the waveguide is studied. The influence of materials and number of periods on the propagation characteristics of hybrid modes. The hybrid surface plasma waveguides can limit the light field to the deep subwavelength scale and also have the characteristics of low loss. The effective mold volume of 0.005? M _ 3, a waveguide microcavity with a Purcell factor of 3750. The refractive index of the dielectric layer and the propagation characteristics of the waveguide with the addition of small metal strip at the defect position are numerically studied. The results show that the HP-waveguide nanocavity not only has a high Purcell factor but also has good sensing properties. The results of this paper provide a basis for the optimal design of waveguide components based on surface plasmas. Theoretical basis. It is helpful to realize the application of surface plasma wave in ultra-high integrated optical path.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN252

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