Photodiode -- measure power

  • Thread starter lcr2139
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  • #1
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Hello, I would like to measure power from a photodiode. How do I go about doing this? What would the circuit look like?
 

Answers and Replies

  • #2
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I would like to measure the power of a laser through a photodiode, i mean.
 
  • #3
berkeman
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I would like to measure the power of a laser through a photodiode, i mean.
The traditional circuit is a current-to-voltage converter with an opamp:

http://i.stack.imgur.com/hgwKe.gif
hgwKe.gif
 
  • #4
Baluncore
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The circuit given above operates the LED as a photodiode at zero voltage and so measures the short circuit current. Short circuit current is a measure of the flux of photons being received. That current can be converted to power if the wavelength (colour) of the photons is known. You will need to calibrate the system. You may need to use an optical attenuator for higher output lasers.

For better answers more information is needed.
Why do you want to measure the power ?
What is the laser wavelength or colour ?
What is the power supply for the laser ?
Does the laser have a manufacturers part number ?
What sort of photodiode did you plan to use ?
 
  • #5
62
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I successfully hooked up my photodiode to an oscilloscope and got a good reading. Is there a way to measure noise, or SNR?
 
  • #6
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I successfully hooked up my photodiode to an oscilloscope and got a good reading. Is there a way to measure noise, or SNR?

or should i use an optical spectrum analyzer?
 
  • #7
Baluncore
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2021 Award
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I am not a mind reader. Why do you not answer questions?
For better answers more information is needed.
Why do you want to measure the power ?
What is the laser wavelength or colour ?
What is the power supply for the laser ?
Does the laser have a manufacturers part number ?
What sort of photodiode did you plan to use ?
What type of laser are you using?
 

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