OH absorption in on-chip high-Q resonators
Abstract
Thermal silica is a common dielectric used in all silicon-photonic circuits. And bound hydroxyl ions (Si-OH) can provide a significant component of optical loss in this material on account of the wet nature of the thermal oxidation process. A convenient way to quantify this loss relative to other mechanisms is through OH-absorption at 1380 nm. Here, using ultra-high-Q thermal-silica wedge microresonators, the OH absorption loss peak is measured and distinguished from the scattering loss base line over a wavelength range from 680 nm to 1550 nm. Record-high on-chip resonator Q factors are observed for near-visible and visible wavelengths, and the absorption limited Q factor is as high as 8 billion in the telecom band. OH ion content level around 2.4 ppm (weight) is inferred from both Q measurements and by Secondary Ion Mass Spectroscopy (SIMS) depth profiling.
Keywords
Cite
@article{arxiv.2303.17814,
title = {OH absorption in on-chip high-Q resonators},
author = {Lue Wu and Maodong Gao and Jin-Yu Liu and Hao-Jing Chen and Kellan Colburn and Henry A. Blauvelt and Kerry J. Vahala},
journal= {arXiv preprint arXiv:2303.17814},
year = {2023}
}
Comments
4 pages, 3 figures