High-speed high-performance vertical-illumination type 100% Ge-on-Si photodetectors for optical data communications

We present a high-speed high-responsivity vertical-illumination-type 100% Ge-on-Si photodetector (PD) based on silicon photonics technology. At λ=1550nm, the fabricated germanium photodetectors exhibit the responsivity of 0.92A/W, 0.73 A/W, and 0.45A/W for the data rate of 10Gbps, 25Gbps and 40Gbps, respectively. The devices show the -3dB bandwidth (f
_-3dB
) up to 45GHz, and display good eye-openings up to 50Gbps data transmission. These results indicate the readiness of the Ge-on-Si PD for optical network communication applications.