A Broadcast/Multicast-Capable Carrier-Reuse WDM-PON

A novel broadcast/multicast-capable carrier-reuse WDM-PON architecture is proposed. Utilizing the splitting capability of a power splitter and the cyclic property of an arrayed waveguide grating (AWG) at the remote node, the broadcast channel and a dedicated downlink unicast channel can be overlaid and subsequently transmitted to each optical network unit (ONU) simultaneously. Since each ONU can receive a common broadcast channel with electronically coded information, the multicast function can be implemented in a higher layer, similar to the current multicast-capable E-PON or G-PON using IP multicast addresses through a single wavelength channel. Thus, there is no need for reconfiguration of physical connections for multicast services. The proposed approach is different from the approach of overlaying DPSK multicast data onto NRZ unicast data using the same wavelength. As such, this approach does not require an expensive DPSK receiver at each ONU, and high receiver sensitivity can be achieved since there is no need to restrict the extinction ratio (ER) of the NRZ unicast data to a small value. Simulation studies show that this WDM-PON provides acceptable performance with one 10 Gb/s broadcast channel and thirty-two 10 Gb/s downlink unicast channels, and thirty-two 2.5 Gb/s uplink unicast channels. Another advantage of this WDM-PON is that the broadcast channel only causes a small interference with the downlink/uplink unicast channels, and it is shared by all the ONUs. The effect of the optical carrier to subcarrier ratio on the bit error rate performance can be mitigated by increasing the extinction ratio of the delay interferometer used at the remote node.