Characterization of a high-speed radio-frequency sampling and demultiplexing circuit based on the cascade connection of pin photodiodes

Herein, we apply theoretical models to characterize the transfer function and frequency response of a complex optoelectronic circuit that comprises a primary ultrafast sampling circuit followed by a cascade connection of \textsl{N} demultiplexing stages. The successive radio-frequency optoelectronic samplers were based on the cascade connection of positive-intrinsic-negative-photodiodes (PIN-PDs). We developed a procedure to calculate the principal design parameters that allows us to use optical power for each sampling and demultiplexing stage, such that the circuit can be designed based on the application requirements. The results obtained from the theoretical models were compared with the measurements obtained from the 2.5 GS / s sampling circuit connected in cascade with a 1.25 GS / s and a 625MS / s demultiplexing circuit implemented using commercial PIN-PDs.