165-GHz Bandwidth, 0.53 A/W Vertical-Illumination Photodiode Enabled by Interference-Based Absorption Enhancement

We present a vertical-illumination InP/InGaAs photodiode (PD) with a monolithically integrated micro-lens having a 165-GHz bandwidth. Interference-based absorption enhancement resulted in a 0.53-A/W responsivity and a record 70-GHz external bandwidth-efficiency product, while maintaining a broader absorption spectral range compared with conventional resonant cavity enhanced PDs. The PD features an electric field confinement by an inverted p-down structure, which results in a low dark current of approximately 1 pA and low manufacturing variability. In addition, an InP microlens is monolithically integrated to increase the effective aperture by up to 20 μm, which improves assembly tolerance.