利用光频范围贵金属介电常量的虚部远小于其实部绝对值的特点,采用一阶微扰理论得到了对称金属包覆波导横电和横磁导模微扰传播常数的解析公式。针对金属包覆波导传输损耗大的缺陷,提出采用亚毫米尺度的超厚导波层来抑制传输损耗的新方法。微扰公式与精确数值解结果相符。

According to the characteristic of dielectric constants of the noble metals in the visible and near-infrared region,a first-order perturbation theory is applied to obtain the propagation constants of the TE and TM modes in the symmetrical metal-cladding optical waveguide. In the light of the great propagation loss of symmetrical metal-cladding optical waveguide,a method that sub-millimeter scaled guiding layer is used to depress the propagation loss is proposed. Calculated results of first-order perturbation agree well with the numerical approach.