Tunable on‐chip mode converter enabled by inverse design
Hongyin Zhou, Kun Liao, Zhaoxian Su, Tianhao Li, Guangzhou Geng, Junjie Li, Yongtian Wang, Xiaoyong Hu, Lingling Huang
Abstract
Abstract Tunable mode converter is a key component of channel switching and routing for optical communication system by adopting mode‐division multiplexing. Traditional mode converter hardly implements high‐order mode conversion and dynamic tunability simultaneously. In this study, we design a tunable mode converter filled with liquid crystal, which can convert fundamental mode into multiple high‐order modes (TE 0 , TE 1 , and TE 2 ) with a good performance and low intrinsic loss. For this multiple‐objective task, we propose an inverse design framework based on the adjoint method. To experimentally prove our design, a tunable mode converter filled with air or water and a mode demultiplexer are fabricated to implement dynamic routing. The experimental results agree well with the simulation and reveal the crosstalk only around −7 dB. With its performance and efficiency, our proposed design flow can be a powerful tool for multifunction device design.