Here's another one-inch-photodetector using OPA818 with a 2pF@5V InGaAs fiber-coupled photodiode FGA01FC. With a transimpedance gain of 4k7 Ohms the bandwidth is just over 200 MHz. A TIASim model predicts the dark-noise and response reasonably well with a parasitic capacitance (over RF) adjusted to ca 0.12 pF. The spectrum-analyzer settings weren't ideal for looking at the dark-noise which should go down to the thermal-noise of the 4k7 resistor (dashed line) - but here the instrument noise-floor prevents us from seeing that.
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