本文把平面光波或高斯光束对介质光波导的端面耦合等效为电流密度矢量激励,用併矢格林函数描述了介质光波导的端面激励问题.导出了耦合效率等公式.这种理论描述,阐明用併矢格林函数方法可统一处理微波波导的电流激励和光波导的光波端面激励问题. In this paper, the coupling of plane wave or Gaussian beam to the dielectric waveguide is equivalent to the current density vector excitation, and the dichroic Green’s function is used to describe the surface excitation problem of the dielectric waveguide. The theory of coupling efficiency is derived. The dyadic Green’s function method can deal with the current excitation of the microwave waveguide and the wavefront excitation of the optical waveguide uniformly.