Enhanced Negative Thermo-Optic Coefficient in Sputtered Versus Sol-Gel TiO 2 Waveguides

作者：Yiheng Tang, Zequn Chen, Yingchun Wu, Maoliang Wei, Hui Ma, Ji Huang, Yuting Ye, Chunlei Sun, Zongxi Li, Xiaojing Li, Sishuo Zou, Hongtao Lin, Ke Si, Wei Gong, Lan Li · 发表于：IEEE Photonics Technology Letters · 年份：2026 · DOI：10.1109/lpt.2026.3652242 · 被引用次数：1 · 研究领域：Photorefractive and Nonlinear Optics、Photonic and Optical Devices、Magneto-Optical Properties and Applications

Titanium dioxide (TiO2) has garnered significant attention in integrated photonics due to its unique negative thermo-optic coefficient (TOC), a property essential for developing athermal devices and efficient thermo-optic switches on flexible platforms. In this paper, we compare sol-gel and magnetron-sputtered TiO2waveguides, highlighting the dependence of their propagation loss and TOC on the deposition method. Sol-gel amorphous TiO2waveguides exhibit propagation loss of 4.64 dB/cm at 1296.42 nm and TOC of − 2.58 × 10-5K-1, while sputtered amorphous TiO2waveguides show similar propagation loss (4.32 dB/cm at 1304.20 nm) but a three times larger TOC (−7.98×10-5K-1), which is attributed to their higher density and lower porosity. These results provide new insights for the development of waveguide-integrated high-performance thermo-optic devices and are expected to accelerate the advancement of next-generation photonic integrated circuits.