层状结构手性波导的模式特性

发布时间：2018-04-02 14:40

本文选题：层状结构　切入点：手性介质　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：光波导作为一种主要的光波传输手段,在全光网络、光学传感、光信号处理以及光学实验等方面扮演重要角色。基于手性介质制成的光波导,由于其本身的旋光性和对于偏振模式的操控能力,在光信号通讯、微纳光学器件、光路耦合以及相关领域有着不俗的应用前景。本文主要将探究手性波导的模式传输特性。使用能够模拟手性介质的时域有限差分方法,在波导中引入不同的层状结构,研究不同结构对于光场在手性波导当中的传播规律以及偏振性质的影响。本文首先在已有的非色散二维手性介质模拟算法的基础上,得到了三维非色散情况下手性介质的时域有限差分方法,并以这两者为研究工具探究层状的波导结构的模式传输特性。阐述了文中所使用方法的构建思路、适用性以及合理性。讨论了激励源、边界条件的选择,并且分析了编程时算法稳定性和模拟误差。通过算例与模式传输理论比较,验证了其与理论的互恰性。以算法为研究工具,本文研究了基本层状结构波导当中模式传输特性,并比较了不同手性和结构参数对于其中模式变化性质的影响。文中讨论了二维双网格时域有限差分方法与三维算法对于模拟手性介质波导的相同点和不同点。同时,通过对比二维平面波导和三维立体结构手性波导当中的模式变化,分析了在手性介质里模式激发的特性和规律。此外,本文探讨了立体结构手性波导中基本的偏振模式转换特性。研究了引入非手性介质的层状结构对于模式传输的影响。最后,本文研究了具有正负手性介质层状结构波导当中模式特性,同时探讨了多阶模式在圆柱手性波导中的传播规律。具体讨论了周期性结构的相反手性覆盖层波导以及纵向正负手性介质交叠结构的波导:从二维平面结构的波导仿真出发,设计了一种实现模式能量转化的结构,并将其推广到三维立体情况进行验证分析。结合前面的仿真结果,本文对圆柱层状手性波导当中模式的激发变化进行了比较。阐述了该种波导在不同介质结构下场强的分布情况,解释了由于结构导致的模式增强和减弱现象。本文分别从二维和三维情况对层状结构手性波导当中的模式传输特性进行研究,得到了模式激发以及传播方面的性质和规律。为设计层状手性波导光学器件、研究手性波导当中的偏振模式变化提供参考和帮助。
[Abstract]:Optical waveguides, as a major means of optical wave transmission, play an important role in all optical networks, optical sensing, optical signal processing and optical experiments.Optical waveguides based on chiral media have great applications in optical signal communication, micro-nano optical devices, optical path coupling and related fields due to their optical rotation and their ability to control polarization mode.In this paper, the mode propagation characteristics of chiral waveguides are studied.Using the finite-difference time-domain (FDTD) method which can simulate chiral dielectric, different layered structures are introduced into the waveguide to study the effects of different structures on the propagation and polarization properties of the optical field in the chiral waveguide.In this paper, based on the existing algorithms for two-dimensional chiral media simulation, a finite-difference time-domain (FDTD) method for chiral media with three-dimensional nondispersion is proposed.The mode propagation characteristics of layered waveguide structures are investigated by using these two methods.The construction idea, applicability and rationality of the methods used in this paper are expounded.The selection of excitation source and boundary condition is discussed, and the algorithm stability and simulation error are analyzed.By comparing the model transmission theory with an example, the mutual coincidence between the theory and the model transmission theory is verified.Using the algorithm as the research tool, the mode propagation characteristics in the basic layered waveguide are studied, and the effects of different chirality and structure parameters on the mode variation properties are compared.In this paper, we discuss the similarities and differences between the two-dimensional two-grid finite-difference time-domain method and the three-dimensional algorithm for the simulation of chiral dielectric waveguides.At the same time, the characteristics and laws of mode excitation in chiral media are analyzed by comparing the mode changes in two-dimensional planar waveguide and three-dimensional chiral waveguide.In addition, the basic polarization mode conversion characteristics in stereoscopic chiral waveguides are discussed.The effect of layered structure with non-chiral medium on the mode propagation is studied.Finally, the mode characteristics of layered waveguides with positive and negative chiral dielectric structures are studied, and the propagation of multi-order modes in cylindrical chiral waveguides is discussed.The oppositely chiral overlay waveguide with periodic structure and the waveguide with longitudinal positive and negative chiral dielectric overlapping structure are discussed in detail. Based on the waveguide simulation of two-dimensional planar structure, a structure to realize mode energy conversion is designed.And it is extended to the three-dimensional case for verification and analysis.Combined with the previous simulation results, the excitation changes in cylindrical layered chiral waveguides are compared.The distribution of the waveguide in different dielectric structures is described, and the phenomenon of mode enhancement and weakening caused by the structure is explained.In this paper, the mode propagation characteristics in layered chiral waveguides are studied in two and three dimensions, and the properties and laws of mode excitation and propagation are obtained.It provides a reference for designing layered chiral waveguide optical devices and studying the polarization mode change in chiral waveguides.
【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

【共引文献】