矩形芯介质波导色散关系及定向耦合器耦合长度的加权余量法计算

本文用加权余量法导出了用以计算各种条形介质波导色散关系,矩形芯双沟道耦合器耦合长度以及条载型波导色散关系的数学表达式,其精确度较其它近似方法高,且简便易行。     

On the calculation of photoemission and related integrals

Explicit formulae are derived for the integrals which result from the application of the Gilat-Raubenheimer zonal integration method to the calculation of photoemission energy distributions. Furthermore it is shown how such formulae may be used to evaluate certain integrals required for the calculation of the imaginary part of the susceptibility of dielectric constant at zero temperature.     

Metal-Clad Multilayer Waveguide: Circle-Chain Convergent Method and Two Perturbation Methods

Computer modeling studies for the calculation of the propagation constants and attenuation coefficients of TE mode in an asymmetric metal/ dielectric/dielectric layers structure are presented. Two different perturbation methods, circle chain convergent method and Downhill method are used. The last two methods can be used easily for the waveguides consist of any number of layers with complex refractive index due to gain and loss. The developed programs were run on a personal computer and numerical results are presented.     

Fully vectorial eigenmode calculation of dielectric waveguides using a Rayleigh--Ritz method with rational basis functions

A fully vectorial Rayleigh--Ritz method for the eigenmode calculation of dielectric waveguides is presented. It uses the four transversal field components and takes rational functions as an orthonormal basis. This formalism is especially useful near the cutoff frequency and has been applied for the investigation of the polarization properties of the output waveguides in integrated spot-size transformers. This revised version was published online in November 2006 with corrections to the Cover Date.     

阶跃型椭圆光纤的色散特性与几何双折射

本文采用计算介质波导色散关系的叠代矩量法计算阶跃型椭圆光纤两个基本偏振模式的传播常数、几何双折射及群折射率差.本方法简便、有效,能给出与精确数值计算吻合的结果.     

Propagation-mode near-field method for measuring optical waveguides of graded index profile: some considerations on TM-modes

A new set of formulae is developed for profiling refractive index of optical waveguides using the propagation-mode near-field method. Effects of graded-index profile on wave equations for TM-modes are taken into account. Anisotropic waveguides are also studied.     

扩散平面光波导的传递函数方法

引入一种计算光波导传播特性的新方法传递函数方法。给出了公式推导,计算了扩散各向同性及扩散各向异性平面光波导的传播特性,并与其它方法所得结果进行了比较。结果表明用传递函数方法处理折射率渐变分布的光波导问题,计算相对简单,可以得到精确的数值结果。     

Review of numerical and approximate methods for the modal analysis of general optical dielectric waveguides

AbstactAbstact This paper reviews numerical and approximate methods for the modal analysis of general optical dielectric waveguides with emphasis on recent developments. Six groups of methods are reviewed, covering (1) the finite-element method, (2) the finite-difference method, (3) the integral-equation method, (4) methods based on series expansion, (5) approximate methods based on separation of variables, and (6) methods that do not fit into the above groups, ranging from the specialized ones for analysing restricted classes of waveguides to the most general ones for analysing inhomogeneous, arbitrarily-shaped, anisotropic waveguides. Some suggestions with regard to the selection of methods for particular applications are given.     

Applications of the finite difference mode solution method to photonic crystal structures

The finite difference waveguide mode solution method, which has been popularly employed in the study of waveguide modes on various optical and dielectric waveguides, is utilized to calculate the modal characteristics of photonic crystal fibers (PCFs) and planar photonic crystal waveguides and the band diagrams of two-dimensional photonic crystals. Vector guided modes on both PCFs based on the total internal reflection guiding mechanism ('holey fibers') and those resulting from photonic band gap effect are accurately computed, with their effective indexes and field distributions compared with other methods. Calculated dispersion of a single-core holey fiber and coupled-power behavior of a two-core holey fiber are found to agree with measured results. For applications to band diagram calculation and planar photonic crystal waveguide analysis, the finite difference scheme is modified simply by imposing suitable periodic boundary condition. Numerical results for air-column crystals and dielectric-rod crystals are both found to agree well with calculations using other methods.     

左手介质矩形波导导模和表面模的场分布

从麦克斯韦方程组出发,结合电磁场的边界条件,推导出介质矩形波导导模的一般色散方程.对普通介质矩形波导和左手介质矩形波导的导模场分布分别进行了数值模拟.通过对比两种介质矩形波导的导模场分布的模拟结果,发现左手介质矩形波导Ex22模的场分布比普通介质波导Ex00模的场更集中在波导中部.同时,根据处理普通介质矩形波导的Marcatili方法.类比得到左手介质矩形波导表面模的色散方程,并数值模拟了低阶模的场分布,结果表明,能量主要集中在波导的四个角区以及波导的边缘.     

Analysis of open dielectric waveguides using the finite-element penalty method

This paper analyzes open dielectric waveguides using the vector finite-element method and boundary integral equations derived from the second Green's theorem. This finite-element formulation, together with the boundary operator, is solved using a penalty function method. Comparison with previously published results shows good agreement for the analysis of the rectangular dielectric waveguide.     

Fresnel zones for modes and analysis of field fluctuations in random multimode waveguides

The notion of Fresnel zones for modes is introduced, which is analogous to the usual Fresnel zones introduced for rays. It is shown that using Fresnel zones for modes one can simplify the analysis of mode scattering at large-scale and random inhomogeneities of a medium in waveguides. Simple formulae to calculate fluctuations of mode amplitudes are obtained. They are similar to well-known formulae of geometrical optics and to those of the Rytov method used to calculate fluctuations of ray complex amplitudes. Relations deduced can be used for calculating field fluctuations both at regular waveguide points and at caustics.     

高斯分层介质粗糙面光波透射问题的微扰法研究

运用微扰法研究平面波入射分层介质粗糙面的光波透射问题,推出了不同极化状态的透射光波散射系数公式。采用高斯粗糙面来模拟实际的分层介质粗糙面,结合高斯粗糙面的功率谱导出了平面波入射高斯分层介质粗糙面的透射系数计算公式。通过数值计算得到HH极化透射系数随透射光波散射角变化的曲线,讨论底层介质介电常数、中间介质介电常数和厚度、粗糙面参数及入射光波长对透射系数的影响。数值计算结果表明：底层介质介电常数、中间介质介电常数和厚度、粗糙面参数及入射光波长对透射系数的影响是非常复杂的。     

Analysis and design of efficient coupling in photonic crystal circuits

A rigorous analysis and design of efficient coupling from photonic crystal (PhC) waveguides into conventional dielectric waveguides is reported. Closed-form expressions for the reflection and transmission matrices that completely characterize the scattering that occurs at the interface are derived based on an eigenmode expansion technique and a Bloch basis. Analytic expressions are used to analyze the reflection into PhC waveguides. We obtain that negligible reflection can be achieved by choosing a certain interface within a PhC unit cell. Furthermore, analytic expressions are used to design a novel and compact coupler structure in order to achieve high coupling efficiency when broad dielectric waveguides are considered. Thereby, transmission efficiencies near 100 from the fundamental guided Bloch mode into the fundamental waveguide mode are achieved.     

Numerical analysis of dispersion characteristics of flat dielectric waveguides

A method is proposed for calculation of the dispersion characteristics of flat gradient dielectric waveguides. The method is based on numerical integration of a system of ordinary differential equations obtained by differentiation of solutions of the initial boundary-value problem with respect to a parameter.Samara State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 2, pp. 143–147, February, 1993.     

Quasioptical millimeter-wave measurements: Refractive index of thin plates

The refractive index of dielectric sheet materials (polystyrene, polypropylene) and of paraffin is measured at mm-wave frequencies using the specimens as dielectric slab waveguides. The mode wavelengths are measured in the evanescent field outside the slab of monomode and two-mode waveguides in which stationary interference patterns of modal fields are generated. The accuracy of the method is about 0.5%.     

平板波导的非线性耦合

给出了两个平板波导耦合成的定向耦合器,当两波导的间隙为克尔型非线性人质时耦合系数与导波功率的关系的计算公式与计算步骤,给出了耦合区为自聚焦介质及自散焦介质两情况的计算实例,并对计算结果进行了讨论     

Network analysis of eigenvalue problem for multilayer dielectric waveguide consisting of arbitrary number of layers

In this paper, the eigenvalue problem of a multilayer dielectric waveguide consisting of arbitrary number of layers is solved by the microwave network method. A general program with the function of computer graphics has been developed for analyzing the dispersion characteristics and the electromagnetic field distributions of an N layer dielectric waveguide. As examples of practical applications of the program, first, the dispersions and field patterns for the planar waveguides with refractive index of parabolic and exponential profiles are analyzed. Secondly, the procedure of mode conversion and mode separation in dielectric branching waveguides is vividly demonstrated through analyzing the field distributions of asymmetric multilayer dielectric structures and the general rules of mode conversion are discussed. The examples show that the present method possesses the advantages of versatility, rapidity, simplicity and accuracy.     

Waveguide discrete modes in slab and cylindrical FIR laser

The characteristic equation is solved for oversized slab and cylindrical hollow waveguides. The outter medium is a dielectric or a metal for cylindrical waveguides, and a dielectric for slab waveguides. The results are applied to consider the resonance conditions for a FIR laser cavity.     

二维介质柱光子晶体波导的优化设计

通过改变靠近导光区域介质柱的直径和周期,优化设计了二维介质柱光子晶体波导.结果表明：单独增大和减小柱的直径以及增大柱的周期不能提高波导的传输特性;单独减小柱的周期能提高波导的传输特性,获得传输系数小于1 dB,带宽80 nm的波谱;同时减小柱的直径及周期能够极大的提高波导的传输特性,得到了带宽为150~250 nm,传输系数小于1 dB的波谱.