High-performance waveguide-integrated germanium PIN photodiodes for optical communication applications

Silicon photonics integrated circuits development considerably spread in the last past years, and telecommunications and datacom applications are now clearly seen as its targets. With the increasing need of data rates, Si photonics components will have to offer very high speed as well as very low power consumption at lowest costs. The recent developments in photodetection have led to high speed and high responsivity waveguide integrated Ge photodetectors [1-3], with various configurations: butt coupling vs. evanescent coupling, vertical vs. lateral PIN junction. Nevertheless, Germanium absorption beyond 1550nm is limited, and long devices are needed, thus prohibiting Ge based photodiode use in the L-band (1565-1625) used in tele-communication. In this paper, we report on our latest development on very low dark current and high speed lateral PIN germanium photodetectors integrated with Si waveguides fabricated on 200mm and 300mm wafer size, for telecom and datacom applications .