Measuring Power with a Saturated Photodiode

Accurate measurement of optical power is pivotal in many applications and scientific research. However, traditional power meters are unable to measure power levels beyond a certain saturation point, limiting their usefulness in high-power applications. In this technical note, I discuss how optical power can be measured using a saturated photodiode. I demonstrate that by monitoring both the dc photocurrent and ac noise, it is possible to accurately measure power levels beyond its saturation point.