A 106-Gb/s PAM-4 Silicon Optical Receiver

We present a 106-Gb/s four-level pulse-amplitude modulation (PAM-4) silicon optical receiver consisting of a low-noise fully differential transimpedance amplifier (TIA) wire-bonded to a high-speed silicon photonic Ge photodiode (PD). A low-noise operation is achieved through a fully differential TIA architecture, combined with active on-chip biasing for the PD. To the best of our knowledge, this is the first integrated low-power optical receiver to report (sub-) KP4-FEC bit error ratios up to 53 GBd PAM-4 without any digital signal processing or equalization to compensate the receiver. An optical modulation amplitude sensitivity of -5 dBm at 53 GBd is obtained, while consuming 160 mW (1.51 pJ/b at 53 GBd). The receiver achieves the best-reported sensitivities from 32-up to 53-GBd PAM-4, at the lowest reported power consumption.