三个非平行波导间的耦合

提出一种分析非平行波导的简明方法…耦合系数推广法，把非平行波导几何图形的变化直接转化成波导耦合系数中波导间距的变化．即对耦合系数进行了巧妙的推广．把波导间距的变化以指数的形式潜人到耦合微分方程中，建立了非平行三波导系统的耦合方程。这些耦合方程包含了非平行波导传输的全部信息，即非平行波导输出光的振幅和相位，非平行传输波导的长度及其夹角．非平行波导输人端口的间距，能量转换与波导参量的关系等。对这些微分方程作巧妙的数学变换，得到非平行三波导耦合系统输出光的完整分析解，分析和讨论了对称和不对称输人初始条件下三个非平行波导的耦合情况。由此可以优化非平行波导的设计参量。

Coupling Among Three Nonparallel Waveguides

A novel concise analytical method of the coupling among three nonparallel waveguidesextended coupling coefficient method is reported.The change of nonparallel-waveguide geometric shape is directly translated into the one of the interval among the parallel waveguides in the coupling coefficient,in other words,the coupling coefficient is extended technologically,the change of the distance among parallel waveguides is included in coupling equations by exponent,and the novel coupling-mode equations are derived for three nonparallel waveguides.These coupling-mode equations include all information such as the amplitude and phase of the nonparallel waveguides,the distances among input ports and the angle,the propagation distance and the power translating with these parameters,etc..Using the skilled mathematic conversion,the perfect analytical solutions are obtained by solving the equations.The coupling among three nonparallel waveguides is analyed and discussed for symmetrical and asymmetrical initial conditions.In accordance with these analytic solutions,the optimum parameters can be presented for the nonparallel waveguide structures.