Extended Data Fig. 1: Experimental characterization of resonance frequency versus applied voltage.

a, Experimental set-up. OSA, optical spectrum analyser; PD, photodiode. b, Resonance tuning data with error bars. The voltage applied to the AlN actuator is varied in the range ±100 V in order to reveal the hysteresis. The standard deviation (s.d.) of the measured frequency at each voltage value is evaluated using the measured frequency with respect to the fitted frequency on the linear curve. The error bars show ±1 s.d. Inset, magnified view highlighting the difference in scale between the observed hysteresis (that is, the frequency difference between two fitted curves) and the error bars. The overall frequency measurement uncertainty is estimated to be below 15 MHz, smaller than the observed hysteresis.