锥形多模干涉耦合器克服了传统多模干涉(MMI)耦合器结构尺寸大的缺点,满足当前集成光器件高集成度的要求,其成像特性对设计基于它的集成光器件至关重要。根据多模干涉耦合器的自映像原理,对锥形多模干涉耦合器成像特性进行分析,发现成像特性与输入场位置、位置数、多模波导初始宽度及渐变率等参量密切相关,得到成像位置的解析表达式并总结出规律。最后采用导模传输分析法进行数值模拟和有限差分束传输法(FDBPM)进行仿真,验证了理论分析的正确性。根据成像位置表达式和规律,得到锥形多模干涉耦合器的一般成像特性,为用锥形多模干涉耦合器设计集成光器件的研究提供了理论依据和设计参考。 The conical multimode interference coupler overcomes the shortcomings of the traditional multimode interference (MMI) coupler in terms of the size of the structure and meets the requirements of the current high integration of the integrated optical device. Its imaging characteristic is very important for designing the integrated optical device based on it. According to the self-imaging principle of multi-mode interference coupler, the imaging characteristics of the tapered multimode interference coupler are analyzed. It is found that the imaging characteristics are closely related to the input field position, the number of positions, the initial width of the multi-mode waveguide and the fading rate, Analytical expressions of location and summarizes the law. At last, the numerical simulation and finite difference beam transmission method (FDBPM) were conducted by guided mode transmission analysis to verify the correctness of the theoretical analysis. According to the expression and regularity of imaging position, the general imaging characteristics of tapered multimode interference couplers are obtained, which provide the theoretical basis and design reference for the design of integrated optical devices using tapered multimode interference couplers.