Efficient Thermal Tuning for Second-order Silicon Nitride Microring Resonators

Thermal tuning for high-index-contrast silicon nitride second-order ring filter with low tuning power of 52 muW/GHz is analyzed. Efficient tuning of 4.5 GHz/K is demonstrated for these filters. Precise centre wavelength stability of approximately 100 MHz is obtained with temperature feedback controller. Their compact size, large free spectral range, low tuning power and low thermal crosstalk between the filters make these resonators attractive for photonic integration.