Hybrid silicon-barium-titanate tunable racetrack resonators based on chemical solution deposition

Integrated electro-optic tuning devices are essential parts of optical communication, sensors, and optical machine learning. Among the available materials, silicon is the most promising for on-chip signal processing and networks. However, silicon is limited owing to the absence of efficient Pockels electro-optic tuning. Herein, we propose a new hybrid silicon-barium-titanate (Si-BTO) integrated photonic platform, in which the BTO thin film is deposited by the chemical solution deposition (CSD) method. A tunable racetrack resonator is demonstrated to confirm the Pockels electro-optic tuning potential of the BTO thin film. The hybrid racetrack resonator has a tuning efficiency of 6.5 pm/V and a high-power efficiency of 2.16 pm/nW. Moreover, the intrinsic quality factor of the fabricated racetrack resonator is 48,000, which is the highest in hybrid Si-BTO platforms, to the best of our knowledge. The high-speed test verifies the stability of the racetrack resonator. The hybrid Si-BTO technology based on the CSD method has the advantages of low equipment cost and simple fabrication process, which holds promise for low-power electro-optic tuning devices.