▎ 摘　　要

We have demonstrated ultra-small and tunable graphene integrated racetrack silicon photonic resonators by harnessing the unique optoelectronic properties of graphene layer and the racetrack silicon resonators. Previous studies have been focused on the straight waveguide interacting with a graphene layer. To further explore how to effectively increase the interaction length between graphene layer and silicon photonic devices, this paper employs integrated racetrack silicon resonator interacting with graphene layer within the coupling region. These new configurations will reduce the footprints of the graphene integrated silicon photonics to micron size, instead of hundreds of microns or even millimeter size. We have demonstrated relatively large voltage tuning results and large modulation depth when putting the graphene layer within the coupling region of the racetrack microresonator close to the critical coupling condition. Our work offers flexibility and tunability for hybrid graphene silicon photonic systems, as well as future functional hybrid photonic devices and systems. Potential applications include emerging areas such as active silicon photonic devices for high-performance data processing, tele communications, integrated biophotonics, and low-power energy saving optoelectronic devices.