Highly Accurate Straintemperature Measurements

What kind of optical power meter is accurate

Optical Power Meter and accuracy is a contentious issue. The accuracy of most primary reference standards (e.g.,, Length,, etc.) is known to a high accuracy, typically of the order of 1 part in a billion. However the optical power standards maintained by various National Standards Laboratories, are only defined to about one part in a thousand. By the time this accuracy has been further degraded through successive links, instrument calibration accuracy is usually only a few.