Fuente: WIPO "tomato" An optical device includes a first optical resonator and a second optical resonator optically coupled to the first optical resonator. A first heater is thermally coupled to the first optical resonator and a second heater is thermally coupled to the second optical resonator. The second heater is configured to be controlled separately from the first heater. A photodetector is coupled to the optical device to monitor light output from the coupled resonators. A controller applies a common-mode dither to the first heater and the second heater. Prior to applying the common-mode dither, the controller reads a first output from the photodetector. Subsequent to applying the common-mode dither, the controller reads a second output from the photodetector. The controller adjusts voltages applied to the first heater and the second heater based on a comparison between the first output and the second output to compensate for variations between the resonators.