衍射微柱透镜轴向光强分布特性的严格电磁分析

衍射聚焦器件轴向光强分布的焦深和焦移特性，直接决定着系统接收面的装配误差和获得最佳的能量利用率。当器件的口径和面型特征尺寸可与照射波长比拟时，必须考虑光波与衍射器件的电磁作用。利用严格电磁分析方法——时域有限差分法，对有限口径衍射微柱透镜的轴向光强分布进行了严格分析，并且与传统的标量分析方法进行详细比较。分析比较了TE和TM极化波入射情况下，不同面型分布(8台阶，16台阶量化面型和连续面型)的衍射微柱透镜焦深和焦移特性与透镜F数的关系。结果表明透镜轴向光强最大点向透镜面偏移，焦移量的严格计算结果要大于标量计算结果，表明透镜的快聚焦特性，而二者得到的焦深量基本一致，同时两种理论方法都表明透镜焦深和焦移随F数的增加而增加。     

基于高阶辛算法的纳米器件本征问题仿真

研究精确和高效的数值方法是现代纳米器件建模和优化的重要目标之一,而分析大部分纳米器件特性的切入点是确定器件结构的能量本征值和能量本征态。本文提出了一种新的算法—高阶辛时域有限差分法(SFDTD(3,4): symplectic finite-difference time-domain)求解含时薛定谔方程。在时间上采用三阶辛积分格式离散,空间上采用四阶精度的同位差分格式离散,建立了求解含时薛定谔方程的高阶辛时域有限差分算法。将高阶辛算法SFDTD(3,4)用于一维量子阱中盒中粒子和谐振子的仿真中,实验结果表明SFDTD(3,4)法比传统的时域有限差分算法以及高阶时域有限差分算法更加准确,适用于对纳米器件本征问题的长时间仿真。     

基于表面等离子体侧耦合谐振腔的可调类EIT温度传感系统

提出一种基于表面等离子体侧耦合谐振腔的可调类电磁诱导透明(EIT)温度传感系统。利用时域有限差分法(FDTD),探究腔内液体注入量对透射窗口中心波长的影响。结合表面等离子体(SPPs)对周围环境介电性能的敏感性，对该系统的温度传感性能进行了研究。结果表明，注入氯仿和乙醇的共振波长均与温度变化呈线性关系，并且注入氯仿对温度的灵敏度比乙醇更高，可达到0.425 nm/℃。研究成果将为高集成度光开关、传感以及慢光等器件的研制提供理论指导。     

环形谐振腔GaAlAs／GaAs四端口滤波器的仿真与实验研究

基于四端口谐振腔滤波理论，采用时域有限差分法(2D—FDTD)对环行谐振腔的滤波特性进行数值仿真，仿真结果给出多模干涉(MMI)耦合长度与滤波特性的关系．所制作的两种GaAlAs／GaAs平面波导环形谐振腔窄带滤波器的测试结果与仿真结果符合较好．     

一般正交曲线坐标系中的降维时域有限差分法

相对于常规的时域有限差分法(FDTD),降维时域有限差分法(R-FDTD)减少了约1/3的存储量。本文推导得出了一般正交曲线坐标系(GOC)中的降维时域有限差分法的基本公式,给出了其计算步骤,为在一般正交曲线坐标系中应用降维时域有限差分法奠定了基础。数值实验证实了这一方法的有效性。     

二维光子晶体波导分波效率的优化

基于自成像效应(SIE)的多模干涉(MMI),设计了一种二维光子晶体波导二端口分波器.采用时域有限差分法和平面波法作为研究工具,从理论上分析了这种器件的特性,在一定耦合长度下研究光在输出端的透射率,结果表明,选择适当的耦合长度可以使光在两个端口高效率输出.进一步研究得知,通过改变器件内部一个介质柱的半径,可以提高光在输出端的透射率.     

时域有限差分法及在光电子学中的应用（一）

时域有限差分法是近几年来发展很快的一种求解电磁问题的数值方法。这种方法适应性强，所用计算机存储单元少，已在许多领域得到大量应用。介绍了时域有限差分法的基本原理和在光电子学中的一些应用。     

利用时域有限差分法进行光波导器件的仿真

将理想匹配层（PML）吸收边界条件用于平面光波导结构的时域有限差分法（FDTD）分析，并对微腔体谐振环进行了数值计算模拟。证明了采用PML吸收边界条件的FDTD法应用于平面光波导结构分析的有效性。本方法对平面光波导的计算机辅助设计（CAD）具有实际意义，可用于分析任意复杂结构的平面光波导。     

光子晶体波导定向耦合光功分器的设计与优化

基于波导定向耦合原理设计了一种全新的光子晶体波导定向耦合光功分器.采用时域有限差分法对这种器件的光波传输特性进行了数值分析,结果表明:本征模色散曲线之间相交;器件的尺寸比传统光功分器更小;入射到光功分器的能量平均分配到输出端,且光波透射率高达95%.这些优异特性对于制造大带宽、高透射率和结构紧凑的光电器件具有极大的应用价值.     

用PCS提高QWIP-LED光提取效率的仿真研究

量子阱红外探测器发光二极管(Quantum Well Infrared Photodetector Light Emitting Diode,QWIP-LED)是一种新型红外上转换器件,配合电荷耦合器件(Charge Coupled Device,CCD)能够实现中波红外成像探测。与常规红外成像器件相比,QWIP-LED最大的优势在于成本低。然而,QWIP-LED较低的光提取效率(约2%)严重制约了该器件的广泛应用。以提高QWIP-LED的光提取效率为目标,在LED表面引入二维光子晶体薄膜(Photonic Crystal Slab,PCS)结构,采用时域有限差分法(Finite-Difference Time-Domain,FDTD)计算了其对光提取效率的改善效果,并对PCS的结构参数进行了优化。仿真结果表明,优化的PCS可以使QWIP-LED的光提取效率提高2.32倍。最后,基于PCS的能带理论以及等效介质理论,对PCS结构提高器件光提取效率的机理进行了分析。     

A scalar finite-difference time-domain approach to guided-wave optics

A finite-difference time-domain approach that solves the scalar wave equations is proposed and validated. The propagation, reflection, scattering, and radiation of electromagnetic waves in weakly guiding optical devices are described explicitly in the time domain. The method is applied to the simulation of guided-wave devices such as directional couplers and distributed feedback reflectors. A comparison to known analytical solutions shows good agreement.<>     

Analysis on Mode Field Distribution of Waveguide Grating Coupler by the Scalar FDTD

The scalar two--dimensional finite difference time domain (FDTD) method is applied to simulate the mode field distribution of TE0 of the waveguide grating coupler.Computer simulation shows that the same stable mode field distribution pattern is obtained through the different kinds of driving sources. It is found that the optical field mode is determined by waveguide structure and optical wavelength other than the driving source.According to the mode field distribution, the optimum coupling efficiency can be predicted.Compared with another numerical methods, the CPU- time and memory elements of computer used by FDTD are much less.     

A scalar finite-difference time-domain method with cylindrical perfectly matched layers: application to guided and leaky modes of optical waveguides

A new scheme for the scalar finite-difference time-domain (FDTD) method with perfectly matched layer boundary conditions in cylindrical coordinate system is developed and presented. The FDTD method is applied successfully for the calculation of both guided and leaky modes of optical waveguides with circular symmetry.     

高阶FDTD法分析电-大尺寸光波导器件

高阶时域有限差分(FDTD)法用于电-大尺寸平面光波导器件的时域分析,实现了高阶FDTD法的理想匹配层(PML)吸收边界条件;研究了高阶FDTD法的数值色散特性,并对平行介质带定向耦合器进行了数值模拟,所得结果与解析解非常一致。     

The perfectly matched layer boundary condition for scalarfinite-difference time-domain method

The perfectly matched layer (PML) boundary condition for the scalar finite-difference time-domain (FDTD) method is developed in this letter. It is demonstrated that the PML is suitable and effective in computation of optical waveguides. The results also show how to optimize the parameters of PML     

Propagation constant of weakly guiding optical fibers: a neweigenvalue condition

After Laplace transforming the reduced radial Helmholtz equation for a weakly guiding optical fiber, we derive an eigenvalue condition for its propagation constant. It is expressed in terms of the ratio of two Laplace-transformation integrals. We show the usefulness of this new condition in connection with the numerical solution of the scalar Helmholtz equation     

近红外波长超透镜的设计与仿真

超透镜是超表面在成像领域中具有较大应用潜力的平面光学器件,能够精确调控光的相位、振幅、偏振等信息、兼容互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)制造工艺,在器件轻量化和批量化制造等方面具有很大的发展前景。针对近红外成像镜头的轻量化需求,使用时域有限差分(finite difference time domain,FDTD)软件设计仿真了工作波长为800nm的硅基偏振不敏感超透镜,镜头厚度小于0.5mm,数值孔径为0.41时聚集效率为75。针对FDTD软件仿真时间较长、硬件要求较高、平面波边缘消散等问题,提出了三维和远场计算相结合的仿真方法;利用波印廷矢量和电场强度积分两种方法分别对超透镜聚集效率进行了计算。对比实验表明:三维和远程计算相结合的方法仿真时间降低了70,计算机内存需求降低了50。     

Modeling and simulation of photonic devices by generalized space mapping technique

The generalized space mapping (GSM) technique is employed for modeling and simulation of photonic devices. The mapping is established between the parameter spaces of coarse and fine models so that accuracy of the coarse model is significantly improved for a given range of parameters. To demonstrate the usefulness of this technique, modeling and simulation of an optical waveguide facet is used as an application example. Two methods are adopted for the coarse model, i.e., the transfer matrix method (TMM) and the free space radiation mode (FSRM) method. The time-intensive and accurate finite-difference time-domain (FDTD) method is used as the fine model for model calibration. The mapping-enhanced coarse models show significant improvement in terms of accuracy. Further, a criterion is established to measure the accuracy of the coarse models. It is shown that the FSRM is one order of magnitude more accurate than the TMM for the TE case, however, the two methods have almost the same level of accuracy for the TM case.     

Integral equation analysis for first order vector correction ofarbitrary profiles

The author's semianalytical method of analysis for arbitrary weakly guiding circular and noncircular profiles based on the scalar wave equation is extended and developed to encompass the analysis of the first order vector correction for the zeroth order modes of the scalar wave equation. The method presented implements no approximations in the analysis of the first order correction and retains all the properties of the semianalytical method of analysis previously presented, thus resulting in a method of analysis possessing extremely high accuracy (<10^-5%)