The magnitude of this error is a function of both wavelength and connector type, and, as a result, the power meter should be calibrated with the same fiber and connector with which it is to be used. This application note demystifies how EXFO's IQS-12002 Optical Calibration System can guide. This reflected energy causes the optical power meter to read higher than it would for a coUimated beam equal in power. NIST developed a testing system to provide absolute power calibrations for optical power meters. Due to the fact that this capability largely depends on the quality of the calibration process, it is important to carefully select your calibration provider.