Modes Characteristics in Slab Waveguide with Noble Metal Interfaces

In this paper, a three-layer chip waveguide with ordinary materials was analyzed with the introducing of metal interfaces among the layers, where three types of metals were used: Au, Ag and Cu. The problem has been analyzed theoretically by deriving the characteristic equations as well as solving them numerically in the COMSOL environment. The results showed that the two methods are identical in the absence of metal, but the presence of metal will cause differences between the two methods that decrease for modes with lower orders, and the use of a small thickness of metal will increase the difference between the two methods. Field distributions vary with normalized frequency, metallic interface thickness, and little change with metal type.