Definitions for "Loss Budget"
The maximum amount of power that is allowed to be lost per optical link.
The amount of power lost in the link. Often used in terms of the maximum amount of loss that can be tolerated by a given link.
The total loss introduced by the components (cable, connectors, splices, couplers) in your fiber optic system subtracted from the attenuation (loss) allowed by your system equipment.
Keywords:  acceptable, total, system
The total acceptable loss for a given system.