Thanks for your reply, duak. Your comments made me think about things that I never considered. I've attached a basic schematic showing what I'm working with. Sorry, I don't have any waveforms.
I never considered the op-amp output current limitations. So, using your calculations of 7 mA from 1 SiPM, assuming we put multiple SiPMs in parallel, we get more current (proportional to the number of SiPMs) that we to balance out. With 4 SiPMs, that's roughly 28 mA, and with 16, that's 112 mA, more than 2x the op-amp ratings. In a power supply, if your circuit draws too much current when at a fixed voltage, then the voltage being outputted will decrease in order to fall below the specified current output (at least that's what happens when I draw too much current from a bench power supply). Is it safe to assume the same here, that with so much current, the op-amp output voltage will more or less drop to low values?
I don't really have any conditions of the TIA about current delivery, just that I would like to preserve the signal waveform. I also never considered increasing the feedback capacitance of the feedback loop. That is something I will have to look into and simulate to see how it works.
Thanks for the link to the slides. Hopefully that will get me thinking on ways that I can see the limitations in my design.