A STUDY ON THE COUPLED-MODE THEORY FOR MICROWAVE AND OPTICAL WAVE CIRCUITS AND ITS APPLICATION

本研究的目的是研究基于耦合模理论的耦合波导系统的分析模型，并将其应用于多层和多导体传输线以及耦合线性或非线性光波导的分析。主要研究成果如下：1.对于多层多导体传输线系统，我们提出了基于广义互易定理的耦合模理论和基于奇异摄动技术的耦合模理论，并结合Galerkin矩量法在谱域中建立了非常有效的解析和数值方法.利用耦合模理论，分析了单平面和双平面耦合微带线的色散特性。结果证实，耦合模理论在弱耦合到中等强耦合B上产生足够好的近似 关于我们 在微带之间。建立了非线性光纤耦合的矢量波耦合模理论，并分析了光开关中的偏振效应.提出了一种光栅辅助非对称三波导耦合器作为新型光波长滤波器件。该耦合器由三个不相同的平面波导组成，中间波导的上下表面具有不同周期的波纹。实验结果表明，与传统的光栅辅助双波导耦合器相比，该耦合器具有明显的滤波效果，并且波长响应的旁瓣几乎完全被抑制.本文用解析封闭方法导出了描述平面三波导非线性定向耦合器的自洽一阶耦合模方程。结果表明，通过改变入射到中间波导的弱控制光的相位，强输入信号的输出通道可以在两个最外面的波导之间切换。少

The purpose of this research project is to investigate an analytical modeling of coupled-waveguide systems based on the coupled-mode theory and to develop its application to the analysis of multilayred and multiconductor transmission lines and coupled linear or nonlinear optical optical waveguides. The main results of the research are summarized as follows :1. For the multilayred and multiconductor transmission lines system, we have proposed a coupled-mode theory using the generalized reciprocity theorem and a coupled-mode theory using the singular perturbation technique, and formulated very efficient analytical and numerical approaches combined with Galerkin's moment method in the spectral domain.2. Using the proposed conpled-mode theory, we have analyzed the dispersion characteristics of the coupled microstrip lines placed on a single plane or dual planes. The results confirmed that the coupled-mode theory yields a good enough approximation over a weak to moderately strong coupling b … More etween the microstrips.3. We developed a vector-wave coupled-mode theory for nonlinear optical fiber coupled and demonstrated the polarization effects in the optical swiching.4. We have proposed a grating-assisted asymmetric three-waveguide coupler as a novel optical wavelength filtering device. The conpler consists of three nonidentical planar waveguides in which the upper and lower surfaces of the intermediate waveguide are corrugated with different periods. It has been shown that the proposed coupler yields a remarkably sharper filtering operation than in the conventional grating-assisted two-wavegiode conpler and the sidelobes in wavelength response are almost completely suppressed.5. The self-consistent first-order conpled-mode equations describing a planar three-waveguide nonlinear directional coupler have been derived in an analytically closed. It has been shown that the output channel for the strong input signal can be swiched between two outermost waveguides by changing the phase of a weak control light launched into the intermediate waveguide. Less