A WDM Passive Optical Network With Centralized Light Sources and Multicast Overlay

We propose a novel wavelength-division-multiplexed passive optical network (WDM-PON) architecture to provide a downstream multicast overlay on the conventional point-to-point data service. The differential-phase-shift-keying multicast data is modulated on the same optical downstream carrier with the inverse return-to-zero point-to-point data signal, thus additional light sources are saved. Broadcast or multicast control is realized at the optical line terminal. For each WDM channel, part of the downstream power is re-used as the upstream data carrier, and thus realizes a colorless optical network unit. We successfully demonstrate the proposed WDM-PON with 10-Gb/s downstream point-to-point signals,10-Gb/s downstream multicast signals, and 2.5-Gb/s upstream signals.