3D-electromagnetic (EM) analysis of surface plasmon polaritons (SPPs) excited by a single-mode (SM) propagation of
visible lightwave in an optical fiber has been studied with a 3D-FEM package based on a finite element method. End of
the fiber is formed to be a circular cone by wet etching process, and is FIBed to make a circular truncated conical shape
with a flat circular surface a few micrometers in diameter. The flat end is covered with three layers of asymmetric metalinsulator-
metal structure, thin metallic layer (M1), thick insulator layer (I), and thick metallic layer (M2), respectively.
The outermost M2 layer has FIBed nanoholes to convert light waves at the extremity of the fiber into SPPs efficiently,
and a bright tiny point light source will be generated on the surface of the M2 layer. In this study, the 3D-FEM models
consists of both the MIM structure and the shrinking optical fiber tip coated with a metallic thin film has been designed
and analyzed numerically. By applying perfect electric conductor and perfect magnetic conductor to planes containing
the axis of rotation, the FEM model has a quarter of the circular truncated conical shape. The FEM analysis is formed in
two steps. At the first step, a FEM mode analysis is performed to obtain a solution corresponding to the SM propagation
in the fiber. The second level of action is the FEM analysis of EM field in the whole of model to find a stationary
solution with the solution of mode analysis. Characteristic of wavelength-dependent excitation, propagation, and
focusing of the SPPs will be presented with several experimental results of trial products of the fiber tip.