Large-optical-aperture Top-illuminated 50-Gbaud PIN-PD with High 3-dB Bandwidth at a Low Bias of 1.5 V

High 3-dB bandwidth of 28 GHz at 1.5 V was demonstrated by introducing a capacitance-control layer into a high-responsivity top-illuminated PIN-PD with large optical-aperture diameter of 20 µm for 50-Gbaud operation.