Inverse-designed silicon nitride reflectors.

Area of Science:

• Silicon photonics
• Integrated optics
• Nanophotonics

Background:

• Reflectors are crucial components in silicon photonics for applications like attenuators, filters, and lasers.
• Existing reflector designs often face limitations in compactness and performance.

Purpose of the Study:

• To present novel silicon nitride reflectors designed using inverse design.
• To characterize their performance in terms of reflectivity and bandwidth.
• To demonstrate their suitability for advanced photonic integrated circuits.

Main Methods:

• Utilized inverse design technique to create six silicon nitride reflectors with varying footprints.
• Simulated reflectivity and bandwidth across the 1530-1625 nm wavelength range.
• Fabricated devices on a silicon nitride multi-project wafer using a single etching step.

Main Results:

• Developed reflectors with footprints ranging from 4µm × 3µm to 4µm × 8µm.
• Achieved average simulated reflectivity as high as -0.09 dB for the larger device.
• Demonstrated a 1-dB bandwidth of 172 nm (1508-1680 nm) for the larger reflector.
• Fabricated 4µm × 8µm reflector showed -0.26±0.11 dB reflectivity from 1530-1600 nm.

Conclusions:

• The inverse design technique enables the creation of intricate and compact silicon nitride reflectors.
• The fabricated reflectors exhibit high reflectivity and broad bandwidth, suitable for high-quality factor cavities.
• These devices offer significant potential for applications in lasers, optical communications, and other silicon photonic integrated circuits.