Characterizations of the hybrid Si/GaN microring resonator with asymmetric vertical coupling

Hybrid nanophotonic platforms are thought to be an essential technology for on-chip ultrahigh-bandwidth optical interconnects in futuristic computers. Although various hybrid nanophotonic platforms have been demonstrated, e.g., Si/InP [1], Si/LiNbO₃ [2], Si/Si₃N₄ [3], an all-round hybrid Si/GaN platform that utilizes both the materials to form functional structures has been investigated only by our group recently [4]. Such hybrid nanophotonic platform is expected to be useful not only for nanophotonics but also for microelectromechanical systems (MEMS). In this work, we present a hybrid Si/GaN microring resonator which consists of a flowable oxide-clad GaN ring on top of Si waveguide circuit. The microring structure could potentially be used for high-speed electro-optic modulations.