Inverse design for material anisotropy and its application for a compact X-cut TFLN on-chip wavelength demultiplexer

作者：Jiangbo Lyu, Zhu Tao, Yan Zhou, Zhenmin Chen, Yazhi Pi, Zhengtong Liu, Xiaochuan Xu, Ke Xu, Xu Ma, Lei Wang, Zizheng Cao, Shaohua Yu · 发表于：Opto-Electronic Science · 年份：2023 · DOI：10.29026/oes.2023.230038 · 被引用次数：25 · 研究领域：Photonic and Optical Devices、Photorefractive and Nonlinear Optics、Photonic Crystals and Applications

Inverse design focuses on identifying photonic structures to optimize the performance of photonic devices. Conventional scalar-based inverse design approaches are insufficient to design photonic devices of anisotropic materials such as lithium niobate (LN). To the best of our knowledge, this work proposes for the first time the inverse design method for anisotropic materials to optimize the structure of anisotropic-material based photonics devices. Specifically, the orientation dependent properties of anisotropic materials are included in the adjoint method, which provides a more precise prediction of light propagation within such materials. The proposed method is used to design ultra-compact wavelength division demultiplexers in the X-cut thin-film lithium niobate (TFLN) platform. By benchmarking the device performances of our method with those of classical scalar-based inverse design, we demonstrate that this method properly addresses the critical issue of material anisotropy in the X-cut TFLN platform. This proposed method fills the gap of inverse design of anisotropic materials based photonic devices, which finds prominent applications in TFLN platforms and other anisotropic-material based photonic integration platforms.