All optical power meters which are calibrated to NIST (the US standards body) or any national standards lab will measure optical power to an uncertainty of about +/- 0. 2 dB, any two. Ge detectors have the highest saturation power of the detector types discussed here, so can be useful for high power measurements. Si detectors are inexpensive and provide excellent accuracy at 850 nm and visible wavelengths. While it is always a challenge to know exactly how much error the measurement system has, there are certain identifiable factors that. Often, users assume that the rated calibration uncertainty of the Newport detector or power meter is the only error in their measurements, however, other factors also contribute to measurement uncertainty. Total measurement error is the sum of all possible sources of error, with detector or meter. Total measurement error is the sum of all possible sources of error, with detector or meter uncertainty being one of multiple sources of error in the measurement.
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