A radiation power equalizer for a wavelength division multiplexed optical communication system, the equalizer includes: dropping means (40, 150, 180) for selectively diverting at least part of the one or more radiation components present in WDM radiation received by the radiation power equalizer, the dropping means comprising a 1x2 optical coupler; a channel control unit for selectively controlling transmission of radiation components present in the WDM radiation, the channel control unit being connected to one output of the 1 x2 optical coupler and comprising: filtering means for partitioning the WDM radiation into one or more radiation components corresponding to channels of the WDM radiation; attenuating means for selectively transmitting or blocking said one or more radiation components; and combining means for combining one or more of the radiation components transmitted through the attenuating means to provide combined radiation; the equalizer further including adding means (60, 210, 240) for adding additional radiation components to the combined radiation, wherein the channel control unit is operable to selectively block radiation components whose wavelengths are coincident with those of the additional radiation components added by the adding means (60, 210, 240); monitoring means for measuring power present in said one or more of the radiation components included in the combined radiation and in the additional radiation components added by the adding means (60, 210, 240) and generating one or more corresponding radiation component power indicative signals; and controlling means for receiving said one or more power indicative signals from the monitoring means and further controlling the attenuation provided by the attenuating means as well as controlling amplitude of radiation output by a DFB laser comprised in the adding means (60, 210, 240) so that the selectively transmitted radiation components included in the combined radiation and the added radiation components are substantially of mutually similar power. dropping means (40, 150, 180) for selectively diverting at least part of the one or more radiation components present in WDM radiation received by the radiation power equalizer, the dropping means comprising a 1x2 optical coupler; a channel control unit for selectively controlling transmission of radiation components present in the WDM radiation, the channel control unit being connected to one output of the 1 x2 optical coupler and comprising: filtering means for partitioning the WDM radiation into one or more radiation components corresponding to channels of the WDM radiation; attenuating means for selectively transmitting or blocking said one or more radiation components; and combining means for combining one or more of the radiation components transmitted through the attenuating means to provide combined radiation; filtering means for partitioning the WDM radiation into one or more radiation components corresponding to channels of the WDM radiation; attenuating means for selectively transmitting or blocking said one or more radiation components; and combining means for combining one or more of the radiation components transmitted through the attenuating means to provide combined radiation; the equalizer further including adding means (60, 210, 240) for adding additional radiation components to the combined radiation, wherein the channel control unit is operable to selectively block radiation components whose wavelengths are coincident with those of the additional radiation components added by the adding means (60, 210, 240); monitoring means for measuring power present in said one or more of the radiation components included in the combined radiation and in the additional radiation components added by the adding means (60, 210, 240) and generating one or more corresponding radiation component power indicative signals; and controlling means for receiving said one or more power indicative signals from the monitoring means and further controlling the attenuation provided by the attenuating means as well as controlling amplitude of radiation output by a DFB laser comprised in the adding means (60, 210, 240) so that the selectively transmitted radiation components included in the combined radiation and the added radiation components are substantially of mutually similar power.