Optical bi-stability in cubic silicon carbide microring resonators

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Silicon carbide (SiC) is a promising material for photonic devices due to its unique optical and thermal properties.
• Microring resonators are key components in integrated photonics for wavelength filtering and nonlinear optical signal processing.

Purpose of the Study:

• To investigate and compare the photothermal nonlinear response of suspended cubic silicon carbide (3C-SiC) and 3C-SiC-on-insulator (SiCOI) microring resonators.
• To determine the photothermal nonlinear index for both device types and identify factors influencing their nonlinear behavior.

Main Methods:

• Fabrication of suspended 3C-SiC and SiCOI microring resonators.
• Measurement of photothermal nonlinear response, including bi-stability and thermo-optic hysteresis.
• Analysis of cavity absorption and temperature effects.
• Modeling using coupled mode theory.

Main Results:

• Both suspended 3C-SiC and SiCOI resonators exhibited bi-stability and thermo-optic hysteresis.
• Suspended 3C-SiC resonators showed a significantly stronger photothermal nonlinear response (index of 4.02×10^-15 m²/W) compared to SiCOI resonators (4.32×10^-16 m²/W).
• Differences in nonlinear response were attributed to variations in waveguide absorption, likely due to crystal defect density.

Conclusions:

• Suspended 3C-SiC microring resonators possess a superior photothermal nonlinear response compared to SiCOI.
• The nonlinear optical properties of these resonators can be tuned by engineering waveguide absorption and material quality.
• These findings suggest potential for developing advanced nonlinear photonic devices using 3C-SiC for high-power applications.