AI 中文总结
研究旨在解决高速LiTaO3调制器依赖硅衬底存在的问题，采用硅衬底底切技术悬浮LTOI-MZMs电极区域，降低微波损耗，制作的调制器实现110 GHz带宽等，通过PAM8信号实现460 Gbit/s净数据速率，解锁钽酸锂电光潜力。
AI 中文摘要
薄膜钽酸锂光子集成电路最近被证明是一个很有前途的下一代电光平台，与铌酸锂相比，具有降低直流漂移、更高光功率处理能力和更低双折射等优点。然而，迄今为止报道的高速LiTaO3调制器主要依赖硅衬底，其大介电常数会影响微波速度匹配并带来射频导体损耗，限制了可实现的电光带宽。本文采用硅衬底底切技术悬浮绝缘体上钽酸锂（LTOI）马赫-曾德尔调制器（MZMs）的电极区域，有效解耦行波电极与高介电常数硅衬底晶圆，降低微波损耗，还消除了对寄生表面电导（PSC）引起的氧化物-硅界面损耗的敏感性。制作的MZM实现了110 GHz的3 dB电光带宽，8 mm长器件的半波电压为5.1 V。利用扩展带宽，通过PAM8信号实现了460 Gbit/s的高单通道强度调制和直接检测（IMDD）净数据速率。这些结果表明硅衬底底切是解锁钽酸锂在其原生硅基晶圆平台上的全电光潜力的有效且与工艺兼容的途径。
英文摘要
Thin-film lithium tantalate photonic integrated circuits have recently been demonstrated as a promising next-generation electro-optic platform, offering favorable properties including reduced DC drift, higher optical power handling, and lower birefringence compared to lithium niobate. However, high-speed LiTaO3 modulators reported to date have predominantly relied on silicon substrates, whose large dielectric constant compromises microwave velocity matching and imposes RF conductor losses that limit the achievable electro-optic bandwidth. Here, we implement a silicon substrate undercut technique to suspend the electrode region of lithium-tantalate-on-insulator (LTOI) Mach-Zehnder modulators (MZMs), effectively decoupling the traveling-wave electrodes from the high-permittivity silicon handle wafer, thereby reducing microwave losses. In addition, the undercut removes any susceptibility to parasitic surface conductance (PSC) induced losses of the oxide-silicon interface. The fabricated MZM achieves a 3 dB electro-optic bandwidth of 110 GHz, with a half-wave voltage of 5.1 V for an 8 mm-long device. Exploiting the extended bandwidth, we demonstrate a high single-lane intensity-modulation and direct-detection (IMDD) net data rate of 460 Gbit/s using PAM8 signaling. These results establish silicon substrate undercut as an effective and process-compatible pathway to unlock the full electro-optic potential of lithium tantalate on its native silicon-based wafer platform.
