High-performance Ge photodetectors on silicon photonics platform for optical interconnect

With the rapid development of 5 G communications, artificial intelligence, the Internet of Things and other fields, the increasing demand for data transmission in communication networks has resulted in optical interconnection gradually replacing traditional electrical interconnection in communication. As one of the core devices, the research and development of silicon-based photodetectors has garnered significant attention. Particularly, the advancement of germanium photodetectors (Ge PDs) holds crucial research significance for both academia and industry. Recently, a variety of high-performance photodetectors based on various photoelectric structures, emerging technologies and physical effects have been demonstrated on silicon photonic platforms. In this review, the research progress of Ge PDs is summarized, and the key technologies and processes in the latest development are analyzed. Firstly, the basic principles and performance of photodetectors are briefly introduced. Secondly, the key technology and basic structure of silicon and Ge PD are discussed. The development history of Ge PDs is then reviewed, and new mechanism design and performance improvement technologies are discussed. Finally, the current research frontiers and hotspots of high-performance Ge PDs are summarized, and the future development trends are discussed. It is hoped that this review will be helpful for readers to gain more insights into the latest advancements in high-performance photodetectors in silicon photonics and contribute to further development.