Lei Yuechen, Hu Zhi-Gang, Wang Min, Gao Yi-Meng, Zuo Zhanchun, Xu Xiulai, Li Bei-Bei
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
University of Chinese Academy of Sciences, Beijing 100094, China.
Fundam Res. 2022 Dec 8;3(3):351-355. doi: 10.1016/j.fmre.2022.11.009. eCollection 2023 May.
Tunable whispering-gallery-mode (WGM) microcavities are promising devices for reconfigurable photonic applications such as widely tunable integrated lasers and reconfigurable optical filters for optical communication and information processing. Scaling up these devices demands the ability to tune the optical resonances in an integrated manner over a full free spectral range (FSR). Here we propose a high-speed full FSR magnetic tuning scheme of an integrated silicon nitride (Si N ) double-disk microcavity. By coating a magnetostrictive film on the spokes and the central pad of the Si N cavity, magnetic tuning can be realized using a microcoil integrated on the same chip. An FSR tuning can be achieved by combining magnetostrictive strain with strong optomechanical interactions provided by the double-disk microcavity. We calculate the required magnetic flux density to tune an FSR ( ) as a function of several key geometric parameters, including the air gap, radius, width of the spokes and ring of the double-disk cavities, as well as the thickness of the magnetostrictive film. The proposed structure enables a full FSR tuning with a required magnetic flux density of milli-Tesla (mT) level. We also study the dynamic response of the integrated device with an alternating current (AC) magnetic field driving, and find that the tuning speed can reach hundreds of kHz in the air.
可调谐回音壁模式（WGM）微腔是用于可重构光子应用的有前途的器件，例如用于光通信和信息处理的宽可调谐集成激光器和可重构光学滤波器。扩大这些器件的规模需要能够在整个自由光谱范围（FSR）内以集成方式调谐光学共振。在此，我们提出了一种集成氮化硅（SiN）双盘微腔的高速全FSR磁调谐方案。通过在SiN腔的辐条和中心垫上涂覆磁致伸缩薄膜，可以使用集成在同一芯片上的微线圈实现磁调谐。通过将磁致伸缩应变与双盘微腔提供的强光机械相互作用相结合，可以实现FSR调谐。我们计算了作为几个关键几何参数的函数来调谐FSR（）所需的磁通密度，这些参数包括气隙、半径、双盘腔辐条和环的宽度以及磁致伸缩薄膜的厚度。所提出的结构能够以毫特斯拉（mT）级的所需磁通密度实现全FSR调谐。我们还研究了集成器件在交流（AC）磁场驱动下的动态响应，发现在空气中调谐速度可以达到数百kHz。
