Yin Kun, Jiao Wenting, Wang Lin, Zhu Shiqiang
School of Mechanical Engineering, Zhejiang University, Hangzhou 310007, China.
Zhejiang Lab, Hangzhou 311112, China.
Micromachines (Basel). 2024 Aug 28;15(9):1084. doi: 10.3390/mi15091084.
Mode (de)multiplexers (MDMs) serve as critical foundational elements within systems for facilitating high-capacity communication, relying on mode conversions achieved through directional coupler (DC) structures. However, DC structures are challenged by dispersion issues for broadband mode coupling, particularly for high-order modes. In this work, based on the principles of phase control theory, we have devised an approach to mitigate the dispersion challenges, focusing on a thin-film lithium niobate-on-onsulator (LNOI) platform. This solution involves integrating a customized inverse-dispersion section into the device architecture, offsetting minor phase shifts encountered during the mode coupling process. By employing this approach, we have achieved broadband mode conversion from TE0 to TE1 and TE0 to TE2 within a 300 nm wavelength range, and the maximum deviations were maintained below -0.68 dB and -0.78 dB, respectively. Furthermore, the device exhibited remarkably low crosstalk, reaching down to -26 dB.
模式（解）复用器（MDM）是实现高容量通信系统中的关键基础元件，它依赖于通过定向耦合器（DC）结构实现的模式转换。然而，DC结构在宽带模式耦合方面面临色散问题的挑战，特别是对于高阶模式。在这项工作中，基于相位控制理论的原理，我们设计了一种方法来缓解色散挑战，重点是绝缘体上薄膜铌酸锂（LNOI）平台。该解决方案包括将定制的逆色散部分集成到器件架构中，以抵消模式耦合过程中遇到的微小相位偏移。通过采用这种方法，我们在300nm波长范围内实现了从TE0到TE1以及从TE0到TE2的宽带模式转换，最大偏差分别保持在-0.68dB和-0.78dB以下。此外，该器件表现出极低的串扰，低至-26dB。
