Si Photonic-Integrated Chip Assembly With Waveguide Ge Avalanche Photodiode for 10 Gbps L-Band Optical Access Networks

The receiving characteristics of the silicon photonic-integrated chip assembly consisting of transimpedance amplifiers and butt-joint waveguide germanium avalanche photodiodes with lateral separated absorption and multiplication (SAM) structures were demonstrated based on conventional complementary metal-oxide-semiconductor processes. We experimentally verified a clear open eye diagram at 10 Gbps with a reverse bias of 17 V. Receiving sensitivities of $-$ 22.8 dBm and $-$ 22.0 dBm were obtained for the best and worst polarizations, respectively, with optical signals that had wavelengths longer than those of the absorption edges of Ge at a bit rate of 10 Gbps and a wavelength of 1600 nm. The proposed waveguide butt-joint germanium avalanche photodiodes with lateral SAM structures can be used to receive long wavelengths of downstream signals with low polarization dependence in next-generation optical access network systems.