1$\,\times\,$ 4 Ge-on-SOI PIN Photodetector Array for Parallel Optical Interconnects

High-quality Ge film was epitaxially grown on silicon on insulator using the ultrahigh vacuum chemical vapor deposition. In this paper, we demonstrated that the efficient 1$\,\times\,$ 4 germanium-on-silicon p-i-n photodetector arrays with 1.0 $\mu$m Ge film had a responsivity as high as 0.65 A/W at 1.31 $\mu$m and 0.32 A/W at 1.55 $\mu$m, respectively. The dark current density was about 0.75 mA/cm$^{2}$ at 0 V and 13.9 mA/cm$^{2}$ at 1.0 V reverse bias. The detectors with a diameter of 25 $\mu$m were measured at 1550 nm incident light under 0 V bias, and the result showed that the 3-dB bandwidth is 2.48 GHz. At a reverse bias of 3 V, the bandwidth is about 13.3 GHz. The four devices showed a good consistency.