32 Keysight 81618A/9A and Keysight 81620B/3B/4B/6B/8B Optical Heads User’s Guide3 SpecificationsReference conditionsThe specified conditions during the spectral responsivity calibration, orconditions which are extrapolated from the conditions during calibration.Conditions: power level, beam diameter or fiber type, numerical aperture,wavelength, spectral width, ambient temperature as specified, at the dayof calibration. Noise and drift observed over a specified observation time,with a temperature change of not more than ±ΔT.Relative uncertainty due to polarizationAlso termed polarization-dependent responsivity (PDR), the relativeuncertainty due to polarization is the uncertainty of the displayed powerlevel on the input polarization state, expressed as the difference betweenthe highest and the lowest displayed power. Uncertainty figures are basedupon a 95% confidence level.Conditions: laser source with variable polarization state, generation of allpossible polarization states (covering th e entire Poincaré sphere), constantwavelength, constant power level, angled connector as specified,temperature as specified.NOTE The power meter is adjusted to zero offset by doing a zero operation withdarkened power meter.
