狭缝波导在集成光波导器件和系统中有极为广泛的应用，分析狭缝波导物理过程的理论方法和理论模型对指导该类器件和系统的设计至关重要.本文通过分析狭缝波导的物理机理和模式特性，提出将狭缝波导五层对称结构中的波导和狭缝区域作为一个整体进行分析的理论方法，并引入导模和辐射模共同作用机制，在此基础上，建立了理论模型描述整个狭缝波导结构的电场分布.将得到的理论结果，分别与RSoft软件仿真结果、其他研究者的理论结果以及实际优化设计结果进行比较研究，验证了本文理论方法和模型的正确性、优越性、完备性和实用性. 最后，给出了本文理论模型适用范围的确定方法，以目前常用狭缝波导(基于SOI材料、波导尺寸180 nm×300 nm)为例，适用于狭缝宽度小于96.2 nm情况.本文理论模型作为一种补充，完善了分析光波导性能的耦合模理论体系.

The slotwaveguide is widely used in the integrated optical waveguide devices and systems. Therefore it is very important to develop a practical theoretical method and model for guiding the design of such devices and systems. By means of analyzing the physical mechanism of the slotwaveguide and the modes transmitted in it, a novel theoretical model was built to describe the electric field distribution in the slotwaveguide. The novel theoretical model was developed based on the conditions of regarding the nanowaveguides and the slot region as a whole system and of introducing both the guided wave and the radiating wave in solving the Helmholtz equation. In order to verify the proposed theoretical model, the theoretical results were compared with RSoft simulation results, a practical optimum design reported by other researchers, and a theoretical method developed by other researchers. The comparison results show that the proposed theoretical model has higher accuracy in describing the slotwaveguides. Finally, the significant condition of the proposed theoretical model was analyzed and determined. Take a typical SOI slotwaveguide with the nanowaveguide size of 180 nm×300 nm as an example, the critical slot width worked out at 96.2 nm.