High-Q-factor Al₂O₃ micro-trench cavities integrated with silicon nitride waveguides on silicon

Area of Science:

• Integrated photonics
• Optical microcavities
• Silicon photonics

Background:

• High-quality factor (Q) optical microcavities are crucial for integrated photonic circuits.
• Existing fabrication methods can be complex and limit material integration.
• Silicon photonics offers a scalable platform for optical devices.

Purpose of the Study:

• To design and demonstrate high-Q integrated optical micro-trench cavities on a silicon platform.
• To investigate the optical properties of aluminum oxide micro-trench resonators.
• To enable the integration of novel microcavity materials into silicon photonics.

Main Methods:

• Co-integration of microcavities with silicon nitride bus waveguides.
• Wafer-scale silicon-photonics-compatible fabrication processes.
• Deposition of amorphous aluminum oxide resonator material via sputtering.
• Theoretical and experimental examination of optical properties.

Main Results:

• Demonstrated experimental Q factors exceeding 10^6 for aluminum oxide micro-trench cavities.
• Analyzed the impact of bend radii and film thickness on cavity performance.
• Achieved integration using straightforward, single-step post-processing.

Conclusions:

• The developed micro-trench cavity design offers a promising route for high-Q resonators on silicon.
• This platform facilitates the incorporation of diverse materials, such as rare-earth-doped films for microlasers.
• The technology supports the advancement of wafer-scale integrated photonic devices.