Measured resonance shift as a result of tuning voltage. The linear fit indicates a voltage tuning response of 255 MHz V –1 . Left inset: schematic of the measurement set-up for microresonator tuning measurement with phase-modulation (PM) sideband calibration. ECDL, external cavity diode laser; AFG, arbitrary frequency generator; OSC, oscilloscope; PD, fast photodiode. Right inset: normalized cavity transmission measurement showing electro-optical tuning of an LTOI resonance. Each colour step corresponds to an increase in DC tuning voltage of 5 V.
