有损耗波导中非线性TE波的数值模拟

本文发展了一种以有限元技术为基础的数值方法,用它分析有损耗波导中的非线性TE模。在这种方法中,非线性有损耗波导中TE波与功率有关的复传播常数和局城电场分布,可从这种波导直接得到,没有任何近似。作为这种方法的应用,计算了非线性有损耗波导系统中TE0模的功率色散关系和电场分布。     

Tailoring dispersion properties of photonic crystal waveguides by topology optimization

The paper describes a systematic method for the tailoring of dispersion properties of slab-based photonic crystal waveguides. The method is based on the topology optimization method which consists in repeated finite element frequency domain analyzes, analytical sensitivity analyzes and gradient based design updates. The goal of the optimization process is to come up with slow light, zero group velocity dispersion photonic waveguides or photonic waveguides with tailored dispersion properties for dispersion compensation purposes. Two examples concerning reproduction of a specific dispersion curve and design of a wide bandwidth, constant low group velocity waveguide demonstrate the efficiency of the method.     

An FDTD Analysis of Nonlinear Photonic Crystal Waveguides

We present a modelling technique for analyzing dispersion characteristics of nonlinear photonic crystal waveguides. This technique combines the nonlinear finite-difference time-domain method, based on the numerical simulation of oscillating dipole radiation, with the super cell approach and the periodic boundary conditions. The technique presented makes it possible to calculate the dispersion characteristics of Kerr-like nonlinear photonic crystals waveguides made by removing some scatterers. A numerical tool based on this technique can be used to design various components for integrated optical circuits.     

Dispersion Characteristics of Waveguide Arrays in Optical Spectrum Analyzers

Formulas for calculating the spectral characteristics of waveguide arrays, which are incorporated into waveguide spectrum analyzers based on planar waveguides, channel waveguides, and fiber optical waveguides, are derived taking into account the contribution of both the waveguide dispersion and the material dispersion to the dispersion factor. These formulas are used to study the dependence of the dispersion factor on the waveguide-system parameters for specific models of waveguide arrays. It is shown that consideration of contributions of the waveguide dispersion and material dispersion can affect profoundly the spectral characteristics of waveguide arrays.     

光脉冲在微环耦合谐振光波导中传输线性特性的数值仿真

利用传输矩阵法得到了微环耦合谐振光波导色散关系的一般表达式,并由色散关系出发讨论了光脉冲在微环耦合谐振光波导中传输时的线性特性,包括带宽、群速度、色散和线性相位变化,这些特性对微环耦合谐振光波导在光通信和光传感领域的应用有重要意义. 关键词： 微环光波导 光脉冲线性特性 传输矩阵法 数值仿真     

Numerical investigation of dispersion relations for helical waveguides using the Scaled Boundary Finite Element method

In this paper, the dispersion properties of elastic waves in helical waveguides are investigated. The formulation is based on the Scaled Boundary Finite Element method (SBEFM). With a set of orthogonal unit basis introduced as the contravariant basis, the helical coordinate is firstly considered, where components of tensor retain the dimension of original quantity. Based on the strain–displacement relation, the eigenvalue matrix is obtained about wavenumbers and frequencies. The cross section of the waveguides is discretized by using high-order spectral elements. Moreover, the formulated linear matrix is utilized to design efficient and accurate algorithms to compute the eigenvalues of helical waveguides. Compared with the Pochhammer–Chree curves, the convergence and accuracy of the SBFEM are discussed. Finally, we give some dispersion curves for a wide range of lay angles and analyze in detail properties of cut-off frequency, mode separation and mode transition for elastic wave propagation in the helical waveguides.     

Directional coupler design based on coupled cavity waveguides in photonic crystals

We propose a directional coupler design based on coupled cavity waveguide in photonic crystals. The plane wave expansion is used to give the dispersion of the coupled cavity waveguides and two parallel such waveguides. The couple length is got from the dispersion curves. Based on the research of the dispersion, we present a directional coupler and the transmission property is given. This structure is potentially important for highly efficient directional coupler in integrate optical circuit.     

Vectorial electromagnetic modes in V-shaped dielectric waveguides with application to quantum wire devices

The properties of V-shaped optical dielectric waveguides are investigated in detail using a vectorial finite element method. The fundamental modes exhibit extremely tight, heart shaped near field patterns. The maximum intensity of the fundamental mode is found to be vertically shifted with respect to the geometrical center of the waveguide. Fundamental and higher order mode properties are extensively studied, including mode patterns, dispersion curves and polarization properties. The local mode polarization of the two fundamental modes varies from a horizontal (vertical) orientation at the groove center to TM (or TE respectively) far in the side wings. The optimal design of waveguides for GaAs/AlGaAs quantum wire diode lasers and Quantum Confined Stark Effect modulators grown on V-grooved substrates is discussed.     

Calculation of effective index for different dielectric waveguides structures made of PVCi/PMATRIFE polymers at telecom-wavelength \lambda =1.55\,\upmu m

In this paper, a number of polymeric waveguide structures have been analyzed by using two distinct techniques which are: effective index method (EIM) and numerical simulation based on finite difference method (FDM). The main aim of this investigation is the calculation of effective indexes (EI) of the following structures: rib, ridge and buried channel waveguides at telecom wavelength $\lambda =1.55\,\upmu \hbox {m}$ for different dimensions of waveguide cores varying from 1.5–4  $\upmu \hbox {m}$ . Moreover, other optical propagation characteristics such as: confinement factor, normalized and propagation constant have been studied in TE polarisation. Otherwise the effect of the structure parameters and dimensions on the dispersion characteristics has been investigated. On the other hand, the optical field distribution has been computed using commercial software named OlympIOs. The polymers applied in the design of waveguide structures are the PVCi (n = 1,562 $\lambda = {1.55}\,\upmu $ m) used as core layer and the PMATRIFE (n = 1,409 $\lambda = 1.55\,\upmu $ m) used as substrate or cladding layer. The results obtained using EIM and simulation based on FDM show that effective index and field confinement factor of TE fundamental mode increase monotonously with the increasing dimension of core. The obtained results are in good agreement with published data based on other numerical methods.     

一种水平变化波导中声传播问题的耦合模态法

针对介质参数及海底边界水平变化波导中的声传播问题,本文基于多模态导纳法提出一种能量守恒且便于数值稳定求解的耦合模态方法.将声压表示为一组正交完备的本地本征函数之和,对声压满足的Helmholtz方程在本地本征函数上作投影,推导出关于声压模态系数的二阶耦合模态方程组.耦合矩阵直观描述水平变化因素对模态耦合的贡献.为避免直接求解二阶耦合模态方程组可能遇到的数值发散问题,将其重构为两个耦合的一阶演化方程组,引入导纳矩阵并使用Magnus数值积分方法获得稳定的声场解.利用该耦合模态方法数值计算水平变化波导中的声场,并与COMSOL参考解比较,结果表明该耦合模态理论能够精确求解水平变化波导中的点源及分布源传播问题.     

Dispersion properties of silicon nanophotonic waveguides investigated with Fourier optics

We experimentally investigate the dispersion relation of silicon-on-insulator waveguides in the 1.5 microm wavelength range by using a technique based on far-field Fourier-space imaging. The phase information of the propagating modes is transferred into the far field either by linear probe gratings positioned 1 microm away from the waveguide core or by residual gratings located on the sidewalls of the waveguide. As a result, the dispersion curve of rectangular and slot waveguides as well as the group index dispersion are accurately determined.     

Linear and quadratic dispersion characterization of millimeter-length fibers and waveguides using common-path interferometry

We measured linear and quadratic dispersion on millimeter-length fibers, waveguides, and nanowires based on common-path spectral interferometry. We obtained the linear dispersion parameter, beta', with a relative precision of 1.45 x 10(-4), and extracted the quadratic dispersion parameter, beta', from the Taylor expansion of beta' x beta' values show a discrepancy of < 1% when compared with simulation as well as with measurement results obtained by a conventional Michelson interferometer. Using this method, we experimentally confirmed the sign inversion of the group velocity dispersion of AlGaAs nanowires for what is believed to be the first time.     

用二维时域有限差分法分析条形多层波导

为精确分析条形多层波导和多量子阱波导，本文提出了一种以二维时 限差分法为基础的全波数值方法，给出了场分布的色散特性的数值结果，并与矢量有限元法已有的结果作了比较；文中还研究了以二维时域有限差分法为基础的标量近似技术，提出了它的有效性和精度的局限性。     

微环耦合谐振光波导中的色散控制模型与数值仿真

本文利用传输矩阵法得到了微环耦合谐振光波导的色散关系,讨论了耦合损耗、传输损耗及耦合系数对微环耦合谐振光波导色散的影响,改变耦合损耗、传输损耗及耦合系数可控制其色散曲线的形状、位置、以及带宽,色散曲线的变化及控制对微环耦合谐振光波导在滤波、光信号延迟及缓存等方面的应用有重要意义. 关键词： 光波导 微环光波导 传输矩阵法     

有损耗介质中非线性光导波的数值模拟

发展了一种以有限元法为基础的数值方法，用它分析由损耗任意大小材料构成的平面非线性波导结构所传导的非线性有损耗光波。在这种方法中，从给出的非线性有损耗波导直接得到ＴＥ和ＴＭ波与功率有关的复传播常数和局域电磁场分布。     

渐变折射率光波导的精确分析

本文利用转移矩阵理论和等效衰减系数的概念，导出了渐变折射率光波导的色散方程，数值计算的结果，赢余方程的精度优于目前存在的所有近似方法。     

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.     

Directional coupler wavelength selective filter based on dispersive Bragg reflection waveguide

A new type of wavelength selective filter, based on high differential dispersion between two coupled waveguides, is presented. The Bragg Reflection Waveguide displays high effective refractive index dispersion, due to the interaction of the guided mode with the two confining Bragg reflectors. When coupled with a weakly guided buried channel silica waveguide, a very narrow bandwidth filter (<1 nm) can be easily produced, in a shorter length, with respect to directional couplers made with standard step index channel waveguides. The complete design methodology, fabrication and characterization are presented.     

LIGHTWAVE PROPAGATION IN SUBWAVELENGTH HOLES

In this paper we evaluate methods for calculating dispersion relations for waves with wavelengths of the order of hundreds of nanometres propagating in square waveguides with imperfectly conducting walls. The methods considered here are based on those used previously for rectangular dielectric waveguides.     

耦合谐振器光波导旋转传感的相位灵敏度

利用光学谐振器结构的色散可提高旋转传感的灵敏度, 耦合谐振器光波导可实现强色散, 本文利用传输矩阵理论, 研究耦合谐振器光波导旋转传感的相位灵敏度, 讨论谐振器布局和波导参数对相位灵敏度的影响, 结果表明波导的相位曲线和相位灵敏度依赖于波导中谐振器的布局, 谐振器数量和耦合系数不仅会影响波导旋转传感相位灵敏度曲线峰值的数量和带宽, 还会影响相位灵敏度的大小, 而损耗会降低波导的相位灵敏度, 本文的结果可用于利用谐振器布局和波导参数设计耦合谐振器光波导的相位灵敏度, 对其在旋转传感方面的应用有重要意义. 关键词： 谐振器 旋转传感 光波导