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We describe a design methodology for optimizing an ultra-compact 3 μm long circular high contrast grating (HCG) reflector. A multi-stage optimization process involving parameter optimization (PO) followed by seeded topology optimization (TO) is demonstrated to design a device with performance better than that achieved with PO or TO alone. The device is designed for a foundry process and offers reflection commensurate with waveguide-based Bragg gratings with a significantly higher bandwidth in an ultra-compact footprint. A peak reflectance of 98.9 % was simulated centered at 1569 nm with a minimum reflectance of 97.9 % over C-band.
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Phase-Injected Topology Optimization for Scalable and Interferometrically Robust Photonic Integrated Circuits
We present a novel device-design methodology that produces interferometrically robust photonic integrated circuits on commercial foundry platforms. This new approach, which we call phaseinjected topology optimization, leverages reciprocity to both reduce the computational load and condition the corresponding optimization problem and is compatible with existing adjoint-based design frameworks. We experimentally validate our methodology by designing, fabricating, and testing a 90◦ optical hybrid that operates over C-band and occupies just 8 μm × 8 μm. We measured our device across three different wafers, and observe < ±7◦ of random variability, and a net -10◦ systematic phase deviation between simulation and experiment across all four output arms.
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- Award ID(s):
- 2052808
- PAR ID:
- 10416509
- Date Published:
- Journal Name:
- ACS Photonics
- ISSN:
- 2330-4022
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acsphotonics.2c01016
