A thin film lithium niobate (TFLN) electro-optic modulator based on a partially removed benzocyclobutene (BCB) bonding layer is proposed for sub-terahertz bandwidth. Low-loss microwave transmission is realized by periodic capacitively loaded travelling-wave electrodes (CL-TWEs) with an undercut structure, and the air-filled region beneath the modulator arms is adjusted to secure impedance and velocity matching. A low half-wave voltage length product of 1.2 V·cm can be achieved with 2-µm-gap loaded electrodes, while the 3-dB electro-optic modulation bandwidth for 10 mm modulation length is estimated beyond 300 GHz, thus allowing sub-terahertz operation.

中文翻译：

---

基于底切结构的亚太赫兹带宽电容负载薄膜铌酸锂电光调制器

针对亚太赫兹带宽提出了一种基于部分去除的苯并环丁烯 (BCB) 键合层的薄膜铌酸锂 (TFLN) 电光调制器。低损耗微波传输是通过具有底切结构的周期性电容加载行波电极 (CL-TWE) 实现的，并且调制器臂下方的空气填充区域经过调整以确保阻抗和速度匹配。使用 2 µm 间隙加载电极可以实现 1.2 V·cm 的低半波电压长度乘积，而 10 mm 调制长度的 3 dB 电光调制带宽估计超过 300 GHz，从而允许亚太赫兹操作。