Aluminum Nitride Thin Film Based Reconfigurable Integrated Photonic Devices

In the past few decades, silicon photonics with complementary metal-oxide-semiconductor (CMOS) process compatibility has been well developed and successfully applied to commercial products. Due to the demand for high-fidelity and high-speed optical interconnect, high-resolution sensing, and information processing, hybrid integrating more existing materials to improve performance or introduce novel functionalities with post-CMOS technology becomes essential. Aluminum nitride (AlN) is a popular piezoelectric material widely investigated in the field of Micro-Electro-Mechanical System (MEMS). It has been studied and integrated into photonic integrated circuits (PICs) utilizing the mechanics at micro/nano scale in recent years. Here, we review the recent development of AlN thin film properties and processing. The AlN piezoelectric MEMS transducer technologies are then described, including flexural, surface acoustic wave (SAW), Lamb wave resonators (LWR), and bulk acoustic wave (BAW). After that, photonic devices on hybrid Si-AlN and pure AlN thin film platforms are presented. Finally, the outlooks and perspectives of AlN thin film based reconfigurable integrated photonics are provided.