Feedback regarding circuits design

[ggeorgiev]

Hello everyone

I am designing a circuit to measure the laser power pulse curve. I don't need the actual power or the laser's average power, but the power pulse curve. Therefore, the power of the laser is reduced so that the diode is not damaged.

The circuit consists of a photodiode, a transimpedance amplifier(TIA), and an ADC. The output from the ADC is read and stored with a Raspberry Pi.
The laser has a maximum frequency of 100kHz, and the minimum pulse duration is 10 μs. The rise time of the laser pulse is < 12 μs, and the fall time is < 10 μs.
The photodiode is fast enough to capture the pulse and has a shunt resistance of 1 M and a capacitance of 950 pF. The Dark Current is 20nA.
According to the LTspice simulation, the circuit must function correctly. By functioning, I mean that it is fast enough to capture the 100kHz signals and that it does not oscillate. On the picture, you can see that at 1 mA, I get about 1V at the output.
Since it is about a single circuit, the price of the components is not critical; it simply must work. According to the datasheet, the OPAM is intended for exactly this purpose(fast TIA). The ADC will be the ADS8691, but unfortunately, I couldn't find an LTspice model. I hope that the selection of elements is correct.
I hope that I can reduce the power of the laser to the extent that I can get a photocurrent of about 1mA at 10% of the laser's power. But since I can't estimate it, I plan to replace the R3 with a potentiometer if I need more gain.

I've done some circuits already, but I'm not a professional, and that's why I would be very happy for your feedback!
Here are some specific questions:
1.   Will the circuit work as I imagined at 100kHz? Photodiode + OPAM + ADC + Raspberry, assumed components, circuit and PCB layout are correct.
2.   Should I improve anything to ensure I don't have any problems at 100kHz?
3.   Are there any circuit protection I should consider?
4.   I know the 50-ohm termination in an oscilloscope for high frequencies. Do I have to consider something equivalent to that in my circuit?
I really appreciate any help you can provide!

[Terry Bites]

If your lazy, like most of us, you just use an online tool. eg https://tools.analog.com/en/photodiode/

Or knife and fork it. https://www.mdpi.com/1424-8220/21/10/3455/pdf 

https://www.ti.com/lit/an/sboa220a/sboa220a.pdf?ts=1593413675172&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fdocs%252Funiversalsearch.tsp%253FsearchTerm%253DAnalog%2BEngineer%2527s%2BCircuit%2BCookbook

Or buy a ready made tranisimpedance amp and relax.