Here we report on an electrically-driven, CMOS compatible, ring resonator coupling modulation mechanism based on tuning of free carriers in Indium Tin Oxide (ITO). The modulator device consists of two ITO layers separated by oxide fabricated on the coupling region of silicon ring resonator. Micro ring resonators are extensively used in in integrated photonic applications and are highly sensitive to electro-optical effects. Majority of available ring based modulators are interactivity modulation where active region changes the phase or absorption of the stored optical mode in the cavity. Such devices are essentially limited by the photon lifetime in the cavity. In contrast, coupling modulation devices can change the cross-coupling coefficient of the resonator and take advantage of the non-quasi-static modulation regime. We demonstrate an electrically-driven, CMOS compatible, ring resonator coupling modulation mechanism based on tuning of free carriers in Indium Tin Oxide (ITO). The modulator device consists of two ITO layers separated by oxide fabricated on the coupling region of silicon ring resonator. We are investigating modulation performance of such CMOS compatible coupling modulation devices. We have demonstrated the first reservoir coupling ITO modulator by leveraging critical coupling effects on a SOI ring resonator.
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