This is the average value over the current performance-monitoring interval of the polarization-dependent loss (PDL) measured on this channel during the current performance-monitoring interval, expressed in dB, reflecting how much the signal's loss varies depending on its polarization state as it passes through the optical path. The average PDL over the interval characterizes the typical polarization-sensitivity impairment on this path, which contributes to the overall power budget alongside fixed losses like splices and connectors. For example, an admin qualifying a new amplified span for a coherent upgrade would check polarizationDependentLossAvg to confirm it's within the transponder's tolerance before committing traffic to that path.