In a communication system consisting of multiple nodes, optical interconnects and wave-division multiplexing (WDM), this can be used to broadcast the data stream from any one node-receivers using a broadcast element such as a star coupler. “All-in-all” or “many-to-all” nodes can thus be connected for high speed data transfer. At any receiver node, the optical signal contains all of the wavelengths from all node-transmitters. However, not all of these are necessarily required by all node-receivers. A filter selects the desired wavelengths while the wavelengths containing the extraneous optical signals are typically discarded in the form of heat. The invention achieves energy harvesting by directing (wavelength-filtering) the extraneous wavelengths to an auxiliary (optical power-averaging) photodetector that, through the photovoltaic effect, generates an average dc current that can be used to generate voltage and power to augment the receiver node’s power supply.