@MWNautilus I'd be interested to know more about what parts they selected for their analog front-end. In the paper they don't give any details on it, and the EDA files are not yet available on their website.

Their signal conditioning at the photodiode outputs looks a bit unconventional, with an analog mux directly on the photodiode in a high-sensitivity application. I wonder how they dealt with leakage currents in these chips, and parasitic capacitance affecting bandwidth.