I am a German student. My task is to conduct a characterization of a photodiode (KPEIMC-UDCOM by Kyosemi.) The photodiode will be illuminated by 850-1550 nm laser diodes. It would be good (but not absolutely necessary) if I could do frequency measurements up to 20 MHz.

I'd like to measure the I-V curve, spectral sensitivity, rise/fall time, signal-to-noise ratio etc.

To get a measurable output, I'd like to use a transimpedance amplifier. But that is not what this question is about. My problem is more about the measurement of the voltage and the processing of the data.

I'm not sure whether to use just an oscilloscope, a microcontroller (Arduino?) or something else to get the data and get them plotted.

As I have not much of a background in this topic, it would be nice if you could share some insight on how you would acquire the data for the characteristics I am supposed to investigate.

  • \$\begingroup\$ Bandwidth and SNR will depend on the circuit you integrate the diode into, so you should measure that property of the final system you'll construct, not just the diode. This is especially true if you use a transimpedance amplifier which may change both bandwidth and SNR substantially. \$\endgroup\$ May 8, 2021 at 17:23

1 Answer 1


I'm not sure weather to use just an oscilloscope, a microcontroller (Arduino?) or something else to get the data and get them plotted.

Different measurements need different instruments.

Rise and fall times: you need an oscilloscope

I-V curve: Ideally you want an SMU (source-measure unit) such as the Keithley "Sourcemeter" products.

Responsivity: A good voltmeter

Signal-to-noise ratio is going to be your trickiest measurement. It will be challenging to measure the SNR of the actual photodiode rather than of your transimpedance amplifier and other receiving components. If the SNR is very bad, an oscilloscope will be adequate to measure it. If the SNR is very good you will need some careful design and possibly some expensive equipment.


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