共线声光效应中模式转换效率的理论分析

利用多层结构声表面波的精确模型对决定衍射光栅常数的声表面波传播特性进行了研究，其衍射光栅可使波导中导模向漏模转换，这一现象可用耦合模理论解释。模式转换效率可化作声波频率、声光作用长度、波导厚度和声波功率密度的函数，并利用数值计算得出结果。
关 键 词 共线声光效应; 模式转换效率; 耦合模理论

Abstract The collinear surface acoustic wave properties that determine the induced grating parameters have been investigated using a rigorous modeling of the surface acouseic wave propagation in multiplayer. The guided-to-leaky mode conversion by the induced diffraction grating from surface acouseic wave is analyzed using a generalized multimode formulation of the coupled mode theory. Mode conversion efficiency has been calculated as functions of acoustic frequency, interaction length, guiding layer thickness, and acoustic drive power density.
Key words collinear acoustooptic interaction; mode conversion efficiency; coupled mode theory