We propose a new method to analyze the adiabaticity of a highly multimode tapered waveguide. The propagation of the optical beam in the multimode fiber taper is calculated using the Monte–Carlo ray tracing technique, and then the corresponding phase space of the optical beam is obtained. By calculating the phase space area, the etendue variation of the light is analyzed, and the quantitative criterion for evaluating the adiabaticity of the multimode fiber taper is given based on the etendue conservation principle.

中文翻译：

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多模光纤锥度相空间绝热分析

我们提出了一种分析高度多模锥形波导绝热性的新方法。使用蒙特卡罗射线追踪技术计算光束在多模光纤锥度中的传播，进而得到相应的光束相位空间。通过计算相空间面积，分析光的光展量变化，并基于光展量守恒原理给出评价多模光纤锥度绝热性的量化标准。