提出了一种纳米厚度金属层连接的级联亚波长平面介质光栅三明治结构，利用该结构中纳米金属连接层上下界面处的表面等离子共振的互作用形成多波长共振的特点设计了适用于光通信波段（1 300~1 600 nm）高性能的宽带偏振器和宽带偏振分束器。利用严格耦合波理论分析发现偏振分束器带宽主要由金属连接层厚度控制，光栅厚度基本不影响偏振分束器带宽，只影响共振深度和共振波长。该结论为后续的制备提供了理论指导和借鉴作用。

A wide band polarizer and polarization splitter in the wavelength of 1 300~1 600 nm is designed based on a new structure which is composed of two identical planar dielectric gratings adjoined by thin metallic film. The surface plasmon resonance excited in the above interface of thin metallic layer interacts with one in the bottom interface， which causes multi-wavelength resonance. This characteristic is useful for the wideband. The numerical results by rigorous coupled-wave approach indicate that the wideband is strongly influenced by the thickness of metallic film. The thickness of grating has effects on the deep of resonance and the center wavelength.