An Optical Multicast Overlay Scheme for a WDM PON Using Inverse-RZ-Duobinary Signals

We propose and demonstrate an optical multicast overlay scheme on a wavelength-division-multiplexed passive optical network, employing bandwidth efficient inverse return-to-zero-duobinary signals. Multicast control is realized by tuning the voltage bias at the point-to-point downstream modulator at the optical line terminal. At the optical network unit, one photodetector with two decision modules is used to receive the point-to-point and the multicast data, which lead to low-cost and colorless optical network units. The 10-Gb/s downstream operation of the proposed optical multicast overlay scheme and 2.5-Gb/s carrier distributed upstream transmission have been experimentally demonstrated.