This is the average value over the current performance-monitoring interval of the transmitted optical power measured on the lower-numbered optical lane of this multi-lane coherent port during the current performance-monitoring interval. Averaging this lane's transmit power over the interval shows whether this lane's laser has been holding steady output relative to its sibling high lane. For example, an admin tracking laser aging on a coherent module would compare outOpticalPowerLaneLowAvg against the high lane's average over successive months to see if one lane is degrading faster than the other.