We demonstrate low-voltage germanium waveguide avalanche photodetectors (APDs) with a gain × bandwidth product above 100GHz. A photonic receiver based on such a Ge APD, including a 0.13μm SiGe BiCMOS low-noise trans-impedance amplifier and a limiting amplifier, is realized. A 5.8dB sensitivity improvement is demonstrated at −5.9V bias at an avalanche gain of 6 through bit error ratio measurements. The absolute sensitivity in avalanche mode is −23.4dBm and −24.4dBm at a bit error ratio of 1 × 10−12 and 1 × 10−9 respectively.