Microstructure and domain engineering of lithium niobate crystal films for integrated photonic applications

Photonics: Enabling new applications in optical communication and quantum technologies A review of recent progress in the microstructure and domain engineering of lithium niobate film on insulator (LNOI) has concluded that it is a promising photonic material for developing integrated nonlinear photonic devices. The review, conducted by a team of researchers from China and led by Hong Liu from Shandong University, found that the high-performance electro-optic and nonlinear optical properties of LNOI makes it an ideal platform for integrated photonics. Furthermore, they also discovered that the microstructures could be constructed on LNOI platforms for photonic circuits using current manufacturing techniques such as complementary metal-oxide-semiconductor technology. The researchers concluded that the large-scale and low-cost manufacturing of integrated photonic devices and systems by mature manufacturing processes could lead to the development of new applications in optical communication and quantum technologies. Recently, integrated photonics has attracted considerable interest owing to its wide application in optical communication and quantum technologies. Among the numerous photonic materials, lithium niobate film on insulator (LNOI) has become a promising photonic platform owing to its electro-optic and nonlinear optical properties along with ultralow-loss and high-confinement nanophotonic lithium niobate waveguides fabricated by the complementary metal-oxide-semiconductor (CMOS)-compatible microstructure engineering of LNOI. Furthermore, ferroelectric domain engineering in combination with nanophotonic waveguides on LNOI is gradually accelerating the development of integrated nonlinear photonics, which will play an important role in quantum technologies because of its ability to be integrated with the generation, processing, and auxiliary detection of the quantum states of light. Herein, we review the recent progress in CMOS-compatible microstructure engineering and domain engineering of LNOI for integrated lithium niobate photonics involving photonic modulation and nonlinear photonics. We believe that the great progress in integrated photonics on LNOI will lead to a new generation of techniques. Thus, there remains an urgent need for efficient methods for the preparation of LNOI that are suitable for large-scale and low-cost manufacturing of integrated photonic devices and systems.