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Calculate optical power output of LEDs

  1. Oct 24, 2013 #1
    Hi guys,

    I have to calculate de optical power output of a set of LEDs. For that I used a photodiode to measure the photocurrent at each wavelength and then calculate the optical power at each wavelength using the following formula:

    R (A/W) = I/P,

    where R is the responsivity of the photodiode at each wavelength,
    I is the photocurrent measure with the photodiode at each wavelength and
    P is the optical power output at each wavelength that I want to measure.

    I have de responsivity curve of my photodiode and I have measure the photocurrent. However when calculating de optical power output I obtain very small values.

    For example, for a LED with typical 17000 mlm (from datasheet), I only obtain 0,027 mW (summation of all wavelegths) of optical power. I think that this is a very small value comparing with the value in lumens (17000 mlm).

    Can any on help with this? Am I right? Am I wrong? Is this the right way of calculate optical power?

    Thank you so much
  2. jcsd
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