Tantalum Pentoxide Integrated Photonics: A Promising Platform for Low-Loss Planar Lightwave Circuits with Low Thermo-Optic Coefficients

作者：Zhenyu Liu, Wen Yao, Mingjian You, Xiaolun Yu, Ning Ding, Weiren Cheng, Zhengqi Li, Xingyu Tang, Fei Guo, Dan Lu, Qiancheng Zhao · 发表于：ACS Photonics · 年份：2025 · DOI：10.1021/acsphotonics.4c01485 · 被引用次数：21 · 研究领域：Photonic and Optical Devices、Neural Networks and Reservoir Computing、Optical Network Technologies

Photonic integrated external laser cavities are transformative components in laser frequency stabilization and linewidth narrowing applications. A key challenge in contemporary photonic integration is to realize low-loss waveguides while balancing the thermo-optic response of the cavities. Tantalum pentoxide (Ta 2 O 5 ) has emerged as a promising photonic platform due to its low thermo-optic coefficient (TOC) and low material loss. Incorporating Ta 2 O 5 /SiO 2 waveguides into a photonic circuit requires trade-offs among waveguide loss, device footprints, thermorefractive noise, optical I/O efficiency, and other desired functionalities. In this work, we present a Ta 2 O 5 photonic platform that emphasizes low propagation loss and low thermo-optic sensitivity. We demonstrate that the intrinsic Q factors of these resonators exceed 10 6, corresponding to a propagation loss of 0.27 dB/cm at 1550 nm, using our CMOS-compatible fabrication technique. The temperature-dependent wavelength shift (TDWS) of the Ta 2 O 5 resonators is merely 9 pm/K. The thermorefractive frequency noise of the Ta 2 O 5 microresonators is predicted to be half smaller than that of Si 3 N 4 resonators. Several key building blocks of integrated external laser cavities were demonstrated, including high- Q resonators, self-coupled microresonators, Vernier ring resonators, Sagnac loop mirrors, edge couplers, and Y-branch splitters, which contribute to a comprehensive suite of planar lightwave components on the Ta...