Patent ID: 6904241

Claim:
An optical communications apparatus for power balancing a wavelength division multiplexed (WDM) signal output from an add module adding at least one channel to a signal input thereto, comprising: a gain element optically coupled to the add module and to an add channel port receiving the added at least one channel; said gain element imparting optical gain to the added at least one channel; a controller operatively coupled to said gain element, said controller receiving an input power measurement of the signal input to the add module; and an optical amplifier supplying said signal input to said add module, said controller determining an add path amplification value based on the input power measurement, a through loss associated with a signal passing through the add module, and an add loss associated with a signal traveling an add path of the add module, said controller controlling said gain element according to the add path amplification value, wherein said gain element and said optical amplifier have substantially matching gain profiles such that a portion of a gain profile of said optical amplifier corresponding to a spectrum associated with said added at least one channel substantially matches a portion of a gain profile of said gain element corresponding to said spectrum.