75 GHz germanium waveguide photodetector with 64 Gbps data rates utilizing an inductive-gain-peaking technique

High-performance germanium(Ge)waveguide photodetectors are designed and fabricated utilizing the inductivegain-peaking technique.With the appropriate integrated inductors,the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity.Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed.In this work,the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated,which indicates the high-speed performance of photodetectors using the inductive-gainpeaking technique.

30 GHz GeSn photodetector on SOI substrate for 2 µm wavelength application

We report the demonstration of a normal-incidence p-i-n germanium-tin(Ge_(0.951)Sn_(0.049))photodetector on silicon-on-insulator substrate for 2μm wavelength application.The DC and RF characteristics of the devices have been characterized.A dark current density under−1 V bias of approximately 125 mA/cm^(2) is achieved at room temperature,and the optical responsivity of 14 mA/W is realized for illumination wavelength of 2μm under−1 V reverse bias.In addition,a 3 dB bandwidth(f_(3dB))of around 30 GHz is achieved at−3 V,which is the highest reported value among all group III–V and group IV photodetectors working in the 2μm wavelength range.This work illustrates that a GeSn photodetector has great prospects in 2μm wavelength optical communication.

Horizontal GeSn/Ge multi-quantum-well ridge waveguide LEDs on silicon substrates

A horizontal p-i-n ridge waveguide emitter on a slion(100)substrate with a Gen,g1Sno.c9/Ge multi quantum-well(MQW)active layer was fabricated by molecular beam epitaxy.The device structure was designed to reduce light absorption of metal electrodes and improve injection efficiency.Electroluminescence(EL)at a wavelength of 2160 nm was observed at room temperature.Theoretical calculations indicate that the emission peak corresponds well to the direct bandgap transition(nr-mHr).The light output power was about 2.0μW with an injection current density of 200 kA/cm^2.These results show that the horizontal GeSn/Ge MQW ridge waveguide emiters have great pros-pects for group-IV light sources.