40 Gb/s All-Silicon Photodetector Based on Microring Resonators

We experimentally demonstrate the first all-silicon microring photodetector with 40-Gb/s operation speed based on the defect-assisted subbandgap avalanche mechanism in reverse p-n junction. A novel zigzag p-n junction providing a high responsivity of 48 mA/W upon 8 V in avalanche mode is demonstrated with a low doping concentration of 2 × 10¹⁷ cm^-3 . With the optimized operation wavelength, a 3-dB optical to electrical response of ~20 GHz and high-speed photodetections of 20-40 Gb/s are achieved experimentally, showing great potential in the application of all-silicon ultrahigh-capacity optical interconnects.