【摘要】 本文利用二级微扰近似方法分析了金属包层平板光波导在截止点附近的传输特性 ,将微扰近似所得的结果与本文直接求复本征方程所得的结果进行比较。结果表明 ,微扰法可以给出与精确值符合相当好的数值结果 ,并且可以给出直至截止点的解 ;微扰法的二级近似结果对一级近似结果的修正很小 ,一级近似已可以给出足够精确的结果。更多还原

【Abstract】 The perturbation method is used for an alyzing metal-clad multitilayer waveguides up to near cutoff.The mode propagati on characteristics in near cutoff are discussed in detail,and the results of the first and the second order approximation are compared with those obtained by ex act solution of complex eigenvalue equation.It si demonstrated that the perturba ti on method gives results in good agreement with exact results.It is also demonstr ated that the difference between results of the first and the second order appro ximation is quite small and usually the first order approximation gives sufficie ntly accurate results.更多还原