Independently tunable double Fano resonances based on waveguide-coupled cavities

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Fano resonances offer sharp spectral features crucial for optical devices.
• Silicon microring resonators (MRRs) are key components in integrated photonics.
• Tunable optical devices are essential for advanced functionalities.

Purpose of the Study:

• To demonstrate periodically and independently tunable double Fano resonances (DFRs).
• To explore the application of DFRs in silicon microring resonator (MRR) systems.
• To achieve high-performance optical switching and sensing capabilities.

Main Methods:

• Fabrication of a device using silicon-on-insulator (SOI) and complementary metal-oxide-semiconductor (CMOS) processes.
• Utilizing waveguide-coupled cavities with two silicon MRRs and a feedback-coupled waveguide.
• Employing the thermo-optic effect for independent tuning of DFRs by adjusting MRR resonant wavelengths.

Main Results:

• Successfully demonstrated periodically and independently tunable DFRs.
• Achieved a maximum extinction ratio of 29.20 dB for the Fano resonances.
• Verified independent tunability of DFRs via the thermo-optic effect.

Conclusions:

• The proposed device enables precise control over double Fano resonances.
• The high extinction ratio makes it suitable for high-performance optical applications.
• The device shows promise for multi-wavelength optical switches and high-sensitivity biochemical sensors.