Active phase correction of high resolution silicon photonic arrayed waveguide gratings.

Area of Science:

• Integrated photonics
• Silicon photonics
• Waveguide optics

Background:

• Arrayed waveguide gratings (AWGs) offer flexible spectral filtering.
• Narrow channel spacing in AWGs necessitates long optical paths, increasing device footprint.
• High index contrast waveguides, like silicon-on-insulator (SOI), enable compact AWG designs through tight bends.

Purpose of the Study:

• To design and fabricate compact silicon photonic AWGs with ultra-narrow channel spacings (50, 10, and 1 GHz).
• To address optical phase errors inherent in high index contrast AWGs.
• To demonstrate advanced spectral filtering and RF channelization capabilities.

Main Methods:

• Utilized high index contrast waveguides on SOI wafers for compact AWG designs.
• Integrated thermo-optic phase shifters for active phase error correction.
• Employed two distinct phase error correction methodologies.
• Applied the Gerchberg Saxton algorithm for generating unique spectral filters.

Main Results:

• Fabricated compact AWGs with channel spacings down to 1 GHz.
• Achieved a footprint of only 1.1 cm² for an 11-channel, 1 GHz spaced device.
• Demonstrated state-of-the-art cross-talk performance for high index contrast AWGs.
• Successfully performed RF channelization with 1 GHz resolution.

Conclusions:

• Compact silicon photonic AWGs with active phase correction are feasible for dense spectral filtering.
• The developed devices enable high-resolution RF channelization and custom spectral filter generation.
• This work advances the capabilities of integrated photonic spectral control devices.