A generalization of the concept of multimode interference sensors is presented here for the first time, to the best of our knowledge. The existing bimodal and trimodal sensors correspond to particular cases of those interference sensors. A thorough study of the properties of the multimode waveguide section provided a deeper insight into the behavior of this class of sensors, which allowed us to establish new criteria for designing more sensitive structures. Other challenges of using high-order modes within the sensing area of the device reside in the excitation of these modes and the interpretation of the output signal. To overcome these, we developed a novel structure to excite any desired high-order mode along with the fundamental mode within the sensing section, while maintaining a fine control over the power distribution between them. A new strategy to detect and interpret the output signal is also presented in detail. Finally, we designed a high-order sensor for which numerical simulations showed a theoretical limit of detection of $1.9\times {10}^{-7}$ RIU, making this device the most sensitive multimode interference sensor reported so far.

中文翻译：

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用于光学生物传感应用的八阶多模波导干涉仪

据我们所知，这里是首次对多模干涉传感器的概念进行了概括。现有的双峰和三峰传感器对应于那些干扰传感器的特殊情况。对多模波导部分特性的透彻研究为此类传感器的行为提供了更深入的了解，这使我们能够为设计更敏感的结构建立新的标准。在设备感应区域内使用高阶模式的其他挑战在于这些模式的激发和输出信号的解释。为了克服这些问题，我们开发了一种新颖的结构来激发感测部分中的任何所需的高阶模式以及基本模式，同时对它们之间的功率分配保持良好的控制。还详细介绍了一种检测和解释输出信号的新策略。最后，我们设计了一种高阶传感器，其数值模拟显示了检测到的理论极限。$1.9\times {10}^{-7}$ RIU，使该设备成为迄今为止报道的最灵敏的多模干扰传感器。