Li Qing, Moille Gregory, Taheri Hossein, Adibi Ali, Srinivasan Kartik
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Microsystems and Nanotechnology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Phys Rev A (Coll Park). 2020 Dec;102(6). doi: 10.1103/PhysRevA.102.063506.
Coupled-mode theory (CMT) has been widely used in optics and photonics design. Despite its popularity, several different formulations of CMT exist in the literature, and their applicable range is not entirely clear, in particular when it comes to high-index-contrast photonics platforms. Here we propose an improved formulation of CMT and demonstrate its superior performance through numerical simulations that compare CMT-derived quantities with supermode calculations and full wave propagation simulations. In particular, application of the improved CMT to asymmetric waveguides reveals a necessary correction in the conventional phase matching condition for high-index-contrast systems, which could lead to more accurate photonic circuit designs involving asymmetric elements.
耦合模理论（CMT）已在光学和光子学设计中得到广泛应用。尽管它很受欢迎，但文献中存在几种不同的CMT公式，其适用范围并不完全明确，特别是在高折射率对比度光子学平台方面。在此，我们提出一种改进的CMT公式，并通过数值模拟来证明其卓越性能，这些模拟将CMT导出的量与超模计算和全波传播模拟进行了比较。特别是，将改进后的CMT应用于非对称波导时，揭示了高折射率对比度系统传统相位匹配条件中一个必要的修正，这可能会带来涉及非对称元件的更精确光子电路设计。
