Photonic topology optimization with semiconductor-foundry design-rule constraints

Area of Science:

• Photonics and Optical Engineering
• Materials Science and Engineering
• Computational Science

Background:

• Integrated photonic devices are crucial for modern optical systems.
• Existing design methods often struggle to incorporate complex manufacturing constraints.
• Foundry limitations significantly impact the performance and yield of photonic integrated circuits.

Purpose of the Study:

• To present a unified topology optimization framework for designing manufacturable integrated photonic devices.
• To incorporate diverse manufacturing constraints, including those from commercial semiconductor foundries.
• To enhance device robustness against fabrication variations like over/under-etching.

Main Methods:

• Developed a density-based topology optimization framework.
• Introduced novel methods for minimum-area and minimum-enclosed-area constraints.
• Adapted existing techniques for linewidth, linespacing, and curvature constraints without re-parameterization.
• Utilized differentiable morphological transforms for etch-robustness.

Main Results:

• Successfully integrated multiple manufacturing constraints into the optimization process.
• Demonstrated the framework's ability to design devices robust to over/under-etching.
• Designed three broadband silicon-photonics devices meeting various foundry specifications.
• Validated the methodology across nine different foundry-constraint combinations.

Conclusions:

• The proposed unified framework enables the design of complex integrated photonic devices that satisfy stringent manufacturing requirements.
• The integration of novel constraints and differentiable transforms leads to more robust and manufacturable photonic designs.
• This methodology significantly advances the practical realization of silicon photonics devices for commercial applications.