How to Measure Power Using a Photodiode?

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To measure power from a photodiode, a common approach is to use a current-to-voltage converter circuit with an op-amp, which operates the photodiode at zero voltage to measure short circuit current. This current correlates with the photon flux received, and can be converted to power if the wavelength of the laser is known. Calibration of the system is necessary, and an optical attenuator may be required for high-output lasers. Additional information about the laser's specifications, such as wavelength and power supply, is crucial for accurate measurements. For noise and signal-to-noise ratio (SNR) assessments, using an oscilloscope or an optical spectrum analyzer can be beneficial.
lcr2139
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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?
 
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I would like to measure the power of a laser through a photodiode, i mean.
 
lcr2139 said:
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
 
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 ?
 
I successfully hooked up my photodiode to an oscilloscope and got a good reading. Is there a way to measure noise, or SNR?
 
lcr2139 said:
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?
 
I am not a mind reader. Why do you not answer questions?
Baluncore said:
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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