GeSn lateral p-i-n waveguide photodetectors for mid-infrared integrated photonics

In this Letter, we demonstrate mid-infrared (MIR) lateral p-i-n GeSn waveguide photodetectors (WGPDs) on silicon, to the best of our knowledge for the first time, as a key enabler of MIR electronic-photonic integrated circuits (EPICs). Narrow-bandgap GeSn alloys were employed as the active material to enable efficient photodetection in the MIR region. A lateral p-i-n homojunction diode was designed and fabricated to significantly enhance the optical confinement factor of the guided modes and thus enhance the optical responsivity. Thus, a photodetection range of up to 1950 nm and a good responsivity of 0.292 A/W at 1800 nm were achieved. These results demonstrate the feasibility of planar GeSn WGPDs for monolithic MIR EPICs on silicon. (C) 2021 Optical Society of America

Automated summary

This study demonstrates the first mid-infrared lateral p-i-n GeSn waveguide photodetectors on silicon, utilizing GeSn alloys as the active material to achieve efficient photodetection. By designing and fabricating a lateral p-i-n homojunction diode, optical responsivity was significantly enhanced, leading to a photodetection range of up to 1950 nm with a good responsivity of 0.292 A/W at 1800 nm.