High bandwidth SOI photonic wire ring resonators using MMI couplers

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Devices

Background:

• Ring resonators are key components in photonic integrated circuits.
• Traditional designs using directional couplers face limitations in bandwidth and fabrication.

Purpose of the Study:

• To demonstrate a novel ring resonator design in silicon-on-insulator (SOI) photonic wire waveguides.
• To utilize a compact multi-mode interference (MMI) coupler as the coupling element.
• To evaluate the performance characteristics, including bandwidth, quality factor, and wavelength dependency.

Main Methods:

• Fabrication of ring resonators in SOI photonic wire waveguides.
• Integration of a compact MMI coupler (3 μm x 9 μm) for coupling.
• Characterization of optical performance, including quality factor (Q) and extinction ratio.

Main Results:

• Achieved a high bandwidth of 0.25 nm.
• Obtained a quality factor (Q) of approximately 6000 for 50 μm radius rings.
• Demonstrated wavelength-independent Q and extinction ratio over a >30 nm range.
• Showed no loss penalty for increased bandwidth.

Conclusions:

• The MMI coupler-based SOI ring resonators offer significant advantages over directional coupler designs.
• These resonators exhibit improved performance, including wavelength independence and bandwidth scalability.
• The design presents less demanding fabrication requirements and is compatible with high-speed signal processing and optical delay lines.