Emerging material platforms for integrated microcavity photonics

Many breakthroughs in technologies are closely associated with the deep understanding and development of new material platforms. As the main material used in microelectronics, Si also plays a leading role in the development of integrated photonics. The indirect bandgap, absence of chi((2)) nonlinearity and the parasitic nonlinear absorptions at the telecom band of Si imposed technological bottlenecks for further improving the performances and expanding the functionalities of Si microcavities in which the circulating light intensity is dramatically amplified. The past two decades have witnessed the burgeoning of the novel material platforms that are compatible with the complementary metal-oxide-semiconductor (COMS) process. In particular, the unprecedented optical properties of the emerging materials in the thin film form have resulted in revolutionary progress in microcavity photonics. In this review article, we summarize the recently developed material platforms for integrated photonics with the focus on chip-scale microcavity devices. The material characteristics, fabrication processes and device applications have been thoroughly discussed for the most widely used new material platforms. We also discuss open challenges and opportunities in microcavity photonics, such as heterogeneous integrated devices, and provide an outlook for the future development of integrated microcavities.

Automated summary

This review article summarizes the recently developed material platforms for integrated photonics, with a focus on chip-scale microcavity devices. The characteristics, fabrication processes, and device applications of the most widely used new material platforms are thoroughly discussed. Open challenges and opportunities in microcavity photonics, such as heterogeneous integrated devices, are also discussed, along with an outlook for the future development of integrated microcavities.