Thermally tunable quadruple Vernier racetrack resonators

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Resonator Devices

Background:

• Series-coupled racetrack resonators offer advantages like extended free spectral range (FSR) and enhanced wavelength tunability compared to single resonators.
• The Vernier effect in coupled resonators provides a mechanism for significant spectral response manipulation.

Purpose of the Study:

• To experimentally demonstrate a thermally tunable quadruple series-coupled silicon racetrack resonator exhibiting the Vernier effect.
• To investigate the spectral response characteristics, including FSR extension, wavelength tunability, and peak suppression.

Main Methods:

• Fabrication of a quadruple series-coupled silicon racetrack resonator.
• Utilizing thermal tuning of two individual resonators within the quadruple structure.
• Characterization of the device's spectral response, including transmission spectra and bandwidth.

Main Results:

• Achieved discrete switching of the major spectral peak by 15.54 nm via thermal tuning.
• Demonstrated an extended free spectral range (FSR) of 37.66 nm.
• Obtained significant interstitial peak suppression of 35.4 dB and a 3 dB bandwidth of 0.45 nm.

Conclusions:

• The thermally tunable quadruple series-coupled silicon racetrack resonator effectively utilizes the Vernier effect for enhanced optical performance.
• The device shows promise for applications requiring precise wavelength control and spectral filtering in integrated photonic circuits.