Ge/Si APD Receiver with Record-high Sensitivity Exceeding −30 dBm for 50G PON

A high-responsivity, low-dark-current Ge/Si waveguide APD is demonstrated and achieves ultra-high sensitivities of −30.3 dBm and −30.1 dBm at $50 \text{Gb} / \text{s}$ at $25{ }^{\circ} \text{C}$ and $85{ }^{\circ} \text{C}$ for the first time. This high-performance device reveals the potential of integrated Ge/Si APDs for high-speed PON applications.