Waveguide Ge/Si Avalanche Photodetector with Ultra-High Gain-Bandwidth Product of 1440GHz

A lateral Reach-Through type waveguide Ge/Si avalanche photodetector is presented. The device shows a gain of 20.4 and a bandwidth of approximately 45GHz for −18dBm input optical power under −14V reverse bias voltage, with the corresponding gain-bandwidth product of 918GHz. Furthermore, the device has a gain of 32.1 for −21dBm input optical power, which indicating the proposed avalanche photodetector has a record ultra-high gain-bandwidth product of 1440GHz. The 50Gbps eye-diagrams under different optical power are also measured.