Optimization methodology of 112-Gbaud photoreceivers for Tb / s-class optical communications

Most photoreceivers’ front ends rely on an assembly of a photodiode (PD) and a transimpedance amplifier (TIA) to convert the received optical signal into an amplified electrical one. However, ensuring sufficient electro-optical bandwidth, signal-to noise ratio, and linearity for future $\mathbf{T b} /$ s-class transmitters is challenging as the PD-TIA interconnect becomes a significant issue. We report on an optimization methodology of the front end’s Electro-Optical Response (EOR) in tuning the TIA’s input impedance to eliminate the resonances originating from the interconnection. We also discuss the importance of the photodiode and PD-TIA interface modeling for the optimization process. After adjustment, the front end achieves a $67-\mathrm{GHz}$ Butterworth-like simulated electro-optical response, with 23 GHz bandwidth control and clear 112 -GBd PAM-4 eye-opening. With the proposed method, the front end demonstrates a high resilience to a $+/-30 \%$ interconnection inductance variation.