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类型 综合研究 预答辩日期 2017-11-28
开始(开题)日期 2016-05-31 论文结束日期 2017-09-22
地点 OSC中心会议室 论文选题来源 国家自然科学基金项目     论文字数 7.5 (万字)
题目 数种光波导/光子器件高效数值分析方法研究
主题词 光波导,有限差分法,束传播法,伪谱法,光子集成回路
摘要 近年来,光子集成技术的发展有了长足进步,其中以硅基光子集成回路(PIC)最为显著。硅基PIC的快速发展不仅依赖于成熟CMOS集成电路的制造工艺,还离不开高效率的光波导/光子器件计算机辅助设计(O-CAD)软件支撑。随着PIC集成度的进一步提高,新型材料/结构的应用,对O-CAD软件提出了更高的要求。O-CAD软件的核心是光波导/光子器件数值分析方法。本文针对经典光波导/光子器件数值分析方法存在的问题,结合具体光子器件特点及设计需求,提出了数种改进型光波导/光子器件高效数值分析方法,并通过典型的数值测试或器件设计对其进行了验证。 从Maxwell方程组出发,本文首先推导了用于光波导/光子器件分析的电磁动力学基本方程。在此基础上,提出了一种改进型全失量有限差分模解器模型,该模型通过优化的高精度差分离散处理,使得粗网格划分也能获得更精确结果,从而提高计算效率。 针对广泛存在于光波导/光子器件中的纵向不连续性问题,提出了基于Denman-Beavers迭代算法的高效分析法,该方法比传统方法(如Pade逼近法)具有更快的收敛速度和更好的稳定性。为适应实际光子器件的模拟分析需求,进一步提出了更为复杂的三维半矢量/全失量分析模型,尤其在全失量分析模型中,严格考虑了纵场分量的影响。 其次,重点研究了亟需发展的广角束传播法(WA-BPM)和双向束传播法(WA-BPM)。提出了基于Denman-Beavers迭代的WA-BPM,并通过典型数值测试证明了该方法具有收敛速度快、可正确处理消逝波等优点;针对纵向结构渐变型波导,提出了一种基于窗口剪切和数值移束技术的WA-BPM,该方法可有效的提高计算效率而对精度几乎没有影响;针对平面光波光路的特点,提出了一种基于交替方向隐式的三维WA-BPM,该方法把三维问题转化为二维计算,极大的提高了计算效率;针对Bi-BPM,提出了一种预处理方法,该方法可提高Bi-BPM中迭代求解的收敛速度从而提高效率;此外,本文还提出了一种改进型的双向传输算符计算方案,该方案允许更大的传输步长仍能保证精度,并且可正确的模拟消逝波的物理传输过程。 然后,研究了近年来在光子器件分析中引起关注的高精度多域伪谱法(MD-PSM)。构建了MD-PSM光波导模式求解模型,提出一种基于MD-PSM电场的求解方法,该模型仅需要少量配点即可获得精确结果,计算负担远小于经典的有限差分法。此外,本文还分析了MD-PSM不能很好延伸到BPM算法的原因,并提出了加权方法强加横向边界条件的解决方案,基于此构造了一种稳定的WA-BPM算法,并将此方法应用于波导不连续性问题的分析,然后将两个过程集成起来构建了一种反射式的BPM算法。 针对硅基材料的特点和具体的设计需求,接着构建了以电流源密度为初始激励的频域有限差分法(FDFD)传输分析模型和模式求解模型。使用FDFD设计了一个基于亚波长光栅的的十字交叉槽式纳米线偏振旋转器。器件的旋转区长度仅有12.6μm,工作在1.55μm通信波长时的偏振转换效率、插入损耗和反射损耗分别为97.2%、0.71dB和-20.5dB。此外,该器件可以在260nm的大带宽范围下保证偏振转换效率大于90%、插入损耗低于1dB,高于同类器件水平。 最后,进行了全文总结并给出了未来工作展望。
英文题目 Several efficient numerical techquies for optical waveguides and their devices
英文主题词 Optical waveguide, finite difference method, beam propagation method, pseudospectral method, photonic integrated circuit
英文摘要 Recently, photonic integration technology has made great progress, where the silicon-based photonic integrated circuits (PICs) are the most significant candiates. The rapid development of silicon-based PIC is not only dependent on the matured CMOS processing, but also on the efficient computer aided design softwares for optical waveguides and photonic devices (O-CAD). With the increasing of the integrated density in PICs and the applications of new materials or structures, O-CAD softwares are greatly required. Numerical methods for optical waveguides and photonic devices are the cores of O-CAD softwares. In this thesis, several efficient numerical techniques for optical waveguides and their devices are proposed, aiming at solving some problems from the classical reported methods or providing new solutions to the special design requirements. Firstly, the basic electromagnetic equations for optical waveguides are derived from the Maxwell’s equations. Then an improved full-vectorial finite difference mode solver is proposed. By optimizing the accuracy order of differential discretization scheme, the computational efficiency is improved. To slove the widely existed discontinuity problem in optical waveguides, an efficient numerical method based on Denman-Beavers iterative algorithm is proposed. The present method has advantages of faster convergence rate and better stability than traditional method. Moreover, more complex three-dimensional (3D) semi-vectorial and full-vectorial analysis models are proposed; especially, in the full-vectorial analysis model, the longitudinal field component is strickly included. Next, the wide beam propagation method (WA-BPM) and bidirectional beam propagation method (WA-BPM) are studied. A WA-BPM based on Denman-Beavers iteration is proposed. Typical numerical tests show that the present method has the advantages of fast convergence and the ability of properly dealing with evanescent waves. A WA-BPM based on shifting-beam scheme is proposed for waveguides whose structure slowly varies in the propagation direction. By using a simulation window of proper size, this method can effectively improve the computational efficiency and have little effect on the accuracy. For effiecient analysis of the planar lightwave circuits, an ef?cient 3D semivectorial horizontally WA-BPM based on the alternating direction implicit scheme is proposed. This method transforms the 3D problem into two-dimensional calculation, which greatly improves the computational efficiency. Moreover, a stable and accurate preconditioner for the Bi-BPM is proposed, which improves the convergence speed of the Bi-BPM. In addition, an improved bidirectional propagational operator is proposed, which allows a larger propagation step to ensure accuracy, and can correctly simulate the true physical characteristics of the evanescent waves. Moreover, the highly accurate multi-domain pseudospectral method (MD-PSM), which has attracted attention in the analysis of photonic devices in recent years, has been studied. A full-vectorial mode solver based on MD-PSM for electric fields is proposed. The model can obtain accurate results with only a few collocation points and its computational load is much smaller than the classic finite difference method. Moreover, an ef?cient re?ective BPM based on the MD-PSM is developed. By imposing the lateral boundary conditions through a weighting technique, a transverse characteristic operator like that in the ?nite-difference method (FDM) is constructed so that the BPM techniques for FDM are available. In addition, a finite difference frequency domain method (FDFD) is developed for the design of silicon based photonic devices. A novel polarization rotator (PR) for silicon-based cross-slot waveguides using subwavelength gratings is proposed and analyzed by the FDFD. Numerical results show that a PR of 12.6 μm in length at a wavelength of 1.55 μm is achieved, where the polarization conversion efficiency (PCE) and insertion loss (IL) are, respectively, 97.2% and 0.71 dB, and the reflection loss is below ?20.5 dB for both cases. Moreover, a wide bandwidth of ~260 nm for both polarizations is obtained for keeping the PCE over 90% and IL below 1 dB. Finally, the conclusion of our work is drawn and the outlook for future work is presented.
学术讨论
主办单位时间地点报告人报告主题
光传感/通信综合网络国家 地方联合研究中心 2014.5.27 榴园宾馆 B. M. A. Rahman Finite element method modeling for photonics
光传感/通信综合网络国家 地方联合研究中心 2014.12.6 金陵院304室 吴胜保 Finite-Difference Methods (FDMs)
光传感/通信综合网络国家 地方联合研究中心 2015.6.19 金陵院304室 Zhaowei Liu Using metamaterials & plasmonics to control light
光传感/通信综合网络国家 地方联合研究中心 2015.9.20 金陵院304室 吴胜保 微纳尺度光波导及其器件数值分析方法研究
光传感/通信综合网络国家 地方联合研究中心 2015.11.9 金陵院304室 吴胜保 光波导纵向不连续性问题高精度数值模拟
光传感/通信综合网络国家 地方联合研究中心 2016.5.17 金陵院304室 Patrick Degenaar Biomedical implants: progress and prospects
中国激光杂志社 2015.4.23 金陵院123室 周治平 Photonics Research介绍
光传感/通信综合网络国家 地方联合研究中心 2016.5.22 金陵院304室 吴胜保 数种光波导/光子器件数值分析方法研究
     
学术会议
会议名称时间地点本人报告本人报告题目
16th International Conference on Numerical Simulation of Optoelectronic Devices 2016.7.11-15 澳大利亚 悉尼 An Efficient Wide-Angle Beam Propagation Method Using Denman-Beavers Iterative Scheme
17th International Conference on Numerical Simulation of Optoelectronic Devices 2017.7.24-28 丹麦 哥本哈根 Compact Polarization Rotator for Silicon-Based Cross-Slot Waveguides Using Subwavelength Gratings
全国第17次光纤通信暨第18届集成光学会议 2015.12.19 钟山宾馆 一种新颖束传播法研究
     
代表作
论文名称
An Efficient Semivectorial Bidirectional Beam Propagation Method for 3D Optical Waveguide Structures
Full-Vectorial Analysis of Optical Waveguide Discontinuities Using Denman–Beavers Iterative Scheme
A Pseudospectral Reflective Beam Propagation Method for Optical Waveguides
A Wide-Angle Beam Propagation Method Using Denman–Beavers Iterative Scheme
Analysis of Optical Waveguide Discontinuities Using Denman-Beavers Iterative Scheme
A Stable and Accurate Preconditioner for Bidirectional Beam Propagation Method
An Efficient 3-D Semivectorial Horizontally Wide-Angle Beam-Propagation Method
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
陈健 正高 教授 博导 南京邮电大学
孙小菡 正高 教授 博导 东南大学
赵兴群 正高 教授 硕导 东南大学
蒲涛 正高 教授 博导 解放军陆军工程大学
常建华 正高 教授 博导 南京信息工程大学
      
答辩秘书信息
姓名职称工作单位备注
丁东 副高 副研究员 东南大学