High-responsivity and high-speed germanium photodetector for C + L application

• A novel asymmetric PIN structure optimizes electric field distribution and reduces effective depletion width, enhancing speed. • The photodetector achieves high responsivity of 1.49 A/W at 1550 nm and 1.16 A/W at 1600 nm under -7 V bias. • Bandwidths of 47.1 GHz at 1550 nm and 44.5 GHz at 1600 nm are demonstrated, suitable for high-speed C+L band operation. • The device shows significant potential for next-generation optical communication systems requiring broad bandwidth and high sensitivity.