求解非均匀平面波导导模的一种新方法

本文给出一种新方法,用多层平板波导逼近非均匀平面波导,借助递推公式用牛顿切线法求解本征值方程,以求出非均匀平面波导导模的传播常数与模场分布。本方法优点在于程序简短通用,计算工作量小,求得结果与精确数值解十分吻合(直至近截止区)。本文给出了各种类型的非对称与对称渐变折射率平面波导的结果。     

同时存在横向位移和角度偏差时两平板光波导的连接损耗

用对称平板光波导基模场的高斯近似来计算同时存在横向位移、角度偏差以及波导参数不一样情况两单模平板波导的连接损耗，导出了非常简单的公式，同时也给出了数值计算的实例。     

单纯形法在非线性光波导传播特性分析中的应用

简要介绍了优化理论中的单纯形方法,并且应用到求解介质非线性光波导的色散方程。文中计算了非线性光波导传输特性的2个实例,1）非对称3层平板波导,由线性衬底、克尔型芯区和线性包层（LNL）组成;2）对称3层平板波导,由克尔型包层、衬底及线性芯区组成（NLN）。数值结果表明,非线性光波导的色散方程很困难求解时,单纯形方法对于分析非线性光波导的传输特性简便而且有效。     

同时存在横向位移和角度偏差时两平板光波导的连接损耗

用对称平板光波导基模场的高斯近似来计算同时存在横向位移，角度偏差以及波导参数不一样情况两单模平板波导的连接损耗，导出了非常简单的公式，同时也给出了数值计算的实例。     

平板状双轴旋电磁手征波导中的耦合模理论

本文严格分析了一种新型双轴旋电磁手征波导中耦合模的传输特性。首先，给出了这种双各向异性手征波导中各横向场分量的纵向场分量表示式，由此得到了纵向场分量的耦合模方程，以及平板状双轴旋电磁手征波导中的色散方程。用数值方法研究了它的色散和截止特性，特别考察了双各向异性和手征性引起的波模分裂，转换效应。     

非线性平板波导中均匀芯区场的归一化形式

通过理论分析及典型实例计算，分析了包层及衬底均为非线性Kerr型介质、芯区为线性均匀介质的对称3层平板波导的TE0模出现均匀场分布的条件及其归一化形式。给出了自聚焦和自散焦情况下对称3层平板波导TE0模的归一化场分布曲线以及功率随归一化模折射率变化曲线。     

克尔型薄膜波导的TE0模的精确分析

对于芯区为克尔型非线性介质、覆盖层和衬底为线性介质的平板波导,用雅可比椭圆函数表达芯区场强分布,给出了ＴＥ模的色散方程、场强及功率的数学表达式,改正了已有文献计算式及结果的几处差错,给出了典型实例的正确数据和曲线,所得结果的正确性已采用数值分析法进行核验。     

阵列波导光栅复用器优化设计的数值计算

阵列波导光栅(AWG)复用／解复用器的优化设计计算是集成光波导器件设计计算中的难点．文章应用AWG光信号传输特性和光栅方程，提出了AWG组成部分输入／输出波导、阵列波导、平板波导相关参数及阵列波导结构优化设计的数值计算方法，给出了具体的计算数值；该计算方法解决了AWG复用器优化设计计算的问题，为进一步建立AWG的计算机辅助设计提供了基础．     

改进的非线性薄膜波导导模的无量纲表示

本文对Fontaine所采用的非线性薄膜波导导模的无量纲表示法作了改进,给出了无量纲参数表示的芯区为克尔型非线性介质,衬底和包层为线性介质的LNL型非线性平板光波导的有关计算公式,色散曲线族及场分布和功率分布随模折射率变化关系的曲线族,本法易推广应用于其它非线性平板光波导NLL、NNL及NNN等的处理过程。     

通用二维波导模式数值计算方法及其应用

给出了一种通用精确的二维光波导模式有限差分数值计算方法，在处理波导边界时采用了无穷边界（导数为零）或消逝边界（场为零）在波导内部两种介质的界面处采用了电磁场边界条件，这样可得到标准的本征方程，允许不同波导层采用不同的差分间距，但同一波导要求采用均匀剖分，该方法适用于任何形式的波导。作为应用，文章对金属包层多量子阱光波导的模式双折射特性做了理论分析。     

Finite-element solution of planar arbitrarily anisotropic diffused optical waveguides

The finite-element method for propagation in planar anisotropic diffused optical waveguides with arbitrary permittivity tensor is presented. A Galerkin procedure has been introduced to the finite-element formulation, to study both the nonleaky and leaky surface waves. The complex propagation constants are determined as a function of frequency for possible modes of propagation. The accuracy of the method has been checked by calculating the nonleaky and leaky surface waves of Ti-diffused LiNbO3waveguides with Gaussian index profiles. The numerical results of Ti-diffused LiNbO3waveguides with dielectric overlays are also presented and the effects of dielectric overlays on the propagation characteristics for the nonleaky and leaky surface waves are examined.     

Wavelength dispersion of effective refractive indices of Rb:KTiOPO/sub 4/ optical waveguides

Multimode planar optical waveguides in z-cut KTiOPO/sub 4/ (KTP) substrates have been fabricated using Rb/sup +/:K/sup +/ ion-exchange process. Variations in the refractive index profile and the surface index change with wavelength in these waveguides are approximated by a simple relation. The dispersion characteristics of the effective refractive indices for different guided modes before and after annealing are calculated based on this approximation and the WKB method. Furthermore, the wavelength dispersion can also be expressed using a sellmeier-like equation, and there is an excellent agreement between the calculated values and the measured data.     

Modes in anisotropic optical waveguides formed by diffusion

Solutions of the wave equation are obtained for planar guides whose dielectric constant ε is anisotropic and decreases exponentially in the direction perpendicular to that of wave propagation. Although for TE modes the solutions are quite similar to those obtained earlier for exponentially varying but isotropic ε, there are some singificant differences for TM modes. The condition for single-mode operation and the number of modes of such guides are given in terms of the exponential decay rate, the difference between the surface and bulk values of ε, and the wavelength. The results are illustrated for the cases of Se-diffused CdS and out-diffused LiNbO3.     

负胶-玻璃复合平面光波导传播特性的研究

本文报导了负胶-玻璃复合平面光波导传播特性的实验研究。测量并归纳了负胶介质薄层对银离子交换玻璃平面波导传播特性影响的实验趋势。介绍了弯曲条载波导的实验研究。     

An improved finite-difference vector beam propagation formulationfor graded-index waveguides

An improved finite-difference vector beam propagation formulation for graded-index waveguides is presented. The modification over the existing version involves a more accurate representation of the Fresnel operator in finite-difference form that accounts for the gradient of the refractive index in the vector Hehmholtz equation. The modified scheme is assessed by calculating the TM mode propagation constants of single-mode planar guides that yield better agreement to the exact values over the existing scheme. Furthermore, the calculated coupling lengths of a vertical directional coupler show improved comparison to experimental data     

退火对离子注入铌酸锂平面波导中折射率分布的影响

研究了不同退火条件对氢离子和氦离子注入铌酸锂平面波导中折射率分布的影响。在不同时间和温度下退火处理后用棱镜耦合法测量了两种波导的暗模 ,并给出退火处理前后两种波导的折射率分布。实验结果表明两种离子的注入均造成了损伤层中正常折射率的减小 ,而反常折射率在波导区却有所增加。退火处理对损伤层中的正常折射率分布影响较明显 ,而在 4 0 0℃以下反常折射率几乎不受退火处理的影响     

Coupled mode theory of parallel waveguides

A new coupled mode formulation for parallel dielectric waveguides is described. The results apply to any guided modes (TE, TM, or hybrid) in waveguides of arbitrary cross-section, dissimilar index, and nonidentical shape. Additional index perturbations not included within the waveguides are encompassed by the theory. Propagation constants and mode patterns for the coupled modes computed according to this theory are shown to agree very well with numerical solutions for the system modes when the latter can be determined. Moreover, the new results are more accurate than those obtained from prior coupled mode formulations. It is shown that even for Iossless guides the coupling coefficients from waveguide"b"to"a"and from"a"to"b,"described by kaband kbarespectively, are not related by their complex conjugates if the guides are not identical.     

A simple and accurate model analysis of strip-loaded opticalwaveguides with various index profiles

A simple first-order perturbation approach has been developed to study the propagation characteristics of strip-loaded diffused waveguides with various refractive index profiles. Propagation constants of the guided modes of rib waveguides and strip-loaded waveguides with exponential and Gaussian refractive index profiles are obtained. The results are in good agreement with those reported in the literature that were obtained by variational and numerical techniques. The presented technique provides analytical expressions for the modal field profile that should be useful in the design of various integrated optical devices