High-Responsivity and High-Speed Germanium Photodetector for C + L Band Applications

• A novel asymmetric PIN structure in a Ge photodetector improves electric field distribution and reduces depletion width, enhancing speed. • The device achieves high responsivity of 1.49 A/W at 1550 nm and 1.16 A/W at 1600 nm under weak avalanche at -7 V. • Bandwidths of 47.1 GHz and 44.5 GHz are obtained at 1550 nm and 1600 nm, respectively, enabling high-speed operation. • The fabrication process is simplified using a commercial 140 nm SiPH platform, making it CMOS-compatible and cost-effective.