共查询到20条相似文献,搜索用时 0 毫秒
1.
多层介质波导的一种新方法及其在非均匀介质平面光波导中的应用 总被引:1,自引:0,他引:1
本文提出求解多层介质平面光波导的一个简单而直接的方法。将其应用于非均匀平面光波导,可以求解任意折射率分布和TM模问题。以抛物线型和指数型分布为例,说明只要分层数目足够多,本文介绍的方法可以达到任意精度。 相似文献
2.
提出并优化了用于二维介质柱光子晶体波导与单模平面介质波导对接的基于分布布拉格反射波导的喇叭波导接头,提高了这两种波导之间的传输效率.二维时域有限差分仿真结果表明,在大部分光子晶体波导导模的频谱范围内,传输效率高于98%.传输效率最高可以达到99.85%.
关键词:
光子晶体波导
平面介质波导
时域有限差分 相似文献
3.
利用一维变周期谐振腔阵列和非线性缓变边界,可以实现光波从脊波导到光子晶体平面波导 (PCW)的高效耦合.基于平面波展开法(PWE)和时域有限差分法(FDTD),深入分析和讨 论了普通脊波导、2D-PCW结构和本征模以及工作模式、缓变边界形状等对耦合效率的影响, 从而得出光波从脊波导到2D-PCW、再返回脊波导的统一图景.指出考虑模式转换和采用缓变 边界条件可以极大提高PCW与脊波导间的耦合效率.对PC-PW边界采用线性和非线性缓变结构 进行了仿真,讨论了边界缓变程度对耦合效率的影响.结果表明,采用模式耦合和PC-PW余弦 缓变边界时的耦合效率在较宽的带宽内超过了95%.
关键词:
光子晶体波导
脊波导
PWE
FDTD
耦合边界 相似文献
4.
This paper derives a new approximation for the eigenmodes of a planar waveguide. The approximation is uniformly valid at both the high and low frequency regions of the dispersion relation. It is shown that a Pade approximation of the frequency equation leads to very accurate solutions. The new approximate solution is used to compute the frequency spectrum and the results compared with the exact analytical solution. The solutions presented here are ideal for analytically studying transient wave fields by means of modal summation. 相似文献
5.
Open dielectric waveguides with a gyrotropic layer have been studied with a view to find structures in which the nonreciprocity in the propagation constant is maximized. A prediction based on a qualitative analysis and numerical studies for confirming the theory are included.This work was supported by a contract N00014-79-C-0553 from the Office of Naval Research. 相似文献
6.
Field analysis of a general chiral planar waveguide 总被引:1,自引:0,他引:1
Jianguo Xiao Keqian Zhang Lian Gong 《International Journal of Infrared and Millimeter Waves》1997,18(4):939-948
The propagation characteristics of general chiral planar waveguides are presented. This is the first time the eigen equation
is given in a simple formulation. The results indicate that there are two types of field distribution which is related to
the working wavelength and chiral admittance. When the chiral admittance is larger than a certain value, the fields of one
kind of circularly polarized wave in the core become exponentially damping in the transverse direction.
This work was supported by the “Foundations for the Ph.D Programs of China” 相似文献
7.
Dinesh Kumar 《Optik》2011,122(20):1872-1875
The present paper deals with the theoretical modeling of a nonlinear asymmetrical metal-clad planar waveguide for sensor application to achieve high sensitivity. We take the appropriate field distributions for the proposed structure and impose the boundary conditions to derive the mode equation and other necessary formulae for the proposed sensor. The effect of nonlinearity on the sensitivity of the waveguide is studied. Also, we have compared our computed results with the results given for a similar sensor having five layers structure. It is observed that the sensitivity of the sensor is improved by introducing a nonlinear material in the cover medium. 相似文献
8.
An analysis of a dielectric waveguide periodically loaded with metal strips is presented. Numerical results are obtained from the formulation based on Galerkin's procedure in a space-harmonic domain. Experimental studies are conducted to correlate with theoretical results and to study the effect of finite length of the grating.This work was supported by Office of Naval Research under Contract N00014-79-C-0553. 相似文献
9.
本文将作为参考波导的圆介质波导模式的特征方程进行了有效的近似简化,使之成为独立的四个简单特征方程组。利用这些方程组作为参考波导的特征方程来计算各种复杂波导的传输参数时,能够大大简化计算工作。 相似文献
10.
用精细积分法对含各向异性介质的波导不连续性问题进行了数值模拟与分析. 从矢量波动方程相对应的单变量变分形式出发, 推导出了含有各向异性介质波导横截面离散系数矩阵的表达式, 引入对偶变量, 在Hamilton体系下, 利用精细积分法求出出口刚度矩阵, 进行有限元拼装, 求解了含各向异性介质的波导不连续性问题. 算例表明了该方法的准确性和高效性. 利用本文方法还讨论了介电系数和导磁系数张量的各个分量对波导传输特性的影响.
关键词:
波导不连续性
各向异性介质
Hamilton体系
精细积分法 相似文献
11.
Y. Yamamoto K. Fujisawa T. Takemura S. Kita 《International Journal of Infrared and Millimeter Waves》1988,9(1):29-40
Measurements have been done in the millimeter wave region on a composite waveguide which comprises a dielectric rod waveguide connecting two metal rectangular waveguides. Such a waveguide has been used by us in a Josephson harmonic mixer installed in a small metal cryostat, to prevent the thermal invasion from outside environment and to transmit both signal and LO waves with small losses. The measured transmission loss, that is caused mainly by the coupling loss between metal rectangular waveguides (TE10 mode) and a dielectric rod waveguide (HE11 mode), has been less than 2dB in the frequency range of 52–104 GHz. 相似文献
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14.
研究了退火和二次离子交换对Er3+/Yb3+共掺的磷酸盐玻璃平面光波导传输特性的影响。在退火过程中,由于热效应和波导层Ag+离子的浓度差使得Ag+离子重新分布;随着退火时间的延长和温度的升高,光波导模式数目逐渐增加,波导层深度加深,且波导表面折射率与玻璃基质折射率差减小,退火扩散深度与退火时间的平方根成正比。电子探针结果显示在二次离子交换后形成了掩埋式的光波导,Ag+离子浓度接近二次方分布,而掩埋式的光波导有助于降低光波导的传输损耗。 相似文献
15.
V. K. Kiseliov T. M. Kushta 《International Journal of Infrared and Millimeter Waves》1997,18(1):151-163
A theoretical investigation is presented of scattering characteristics of a perfectly conducting spherical object placed inside
a quasi-optical transmission line of the millimeter and submillimeter waves in the form of a circular hollow dielectric waveguide
(HDW). From the analytical expressions obtained, backscattering and extinction cross sections of this object are derived via
the excitation coefficient of the dominantHE
11 mode of the circular HDW and the HDW geometrical parameters. The agreement of the results with the corresponding data for
the scattering of a plane homogeneous wave is shown. 相似文献
16.
The trigonometric and Hermite-Gaussian basis functions for determining the modal characteristics of inhomogeneous optical waveguides by means of the Galerkin's method are presented and analyzed. The results obtained with each set of basis functions for mode spectra and field distributions are compared with other exact and approximate methods. The merits and problems arising with each set of basis functions are discussed. 相似文献
17.
对于介质薄膜波导的一边或两边复盖有介电常数与光强成正比的非线性介质的三种不同结构,本文导出了三层非线性平面光波导TM波的精确色散关系。对称三层非线性平面光波导的数值计算实例与有限元法的结果完全一致。 相似文献
18.
首次采用了场的最小二乘方 (LSE)和最小均方误差 (LMS)判据寻找平板波导的等效阶跃折射率 (ESI)模型 ,并通过它预测了平板波导的传输特性。计算结果表明 ,原始波导与等效波导场分布在具有最大近似性的基础上 ,ESI模型可以在一定范围内有效的预测平板波导的传输特性。归一化频率与第一个高阶模的截止频率之比在小于 0 7的情况下 ,用上述两种判据找到的ESI模型预测传输常数相对误差小于 0 0 1 % ,预测归一化传输常数的相对误差小于 1 0 %。 相似文献
19.
The impact of fabrication errors on a planar waveguide demultiplexer is analyzed based on an analytical method. The explicit
expression of the transfer function taking into account phase and amplitude errors is presented in order to analyze the loss
and crosstalk of the demultiplexer caused by fabrication errors. A basic requirement for the demultiplexer with a certain
crosstalk criterion can be easily obtained. Using an etched diffraction grating demultiplexer as an example, it is shown that
the analytical results have a good agreement with results from a numerical method. 相似文献