A novel scheme of multicast WDM-PON using modified NRZ signal format

A novel modified Non Return to Zero (NRZ) format is proposed to realize multicast WDM-PON. By adjusting downstream Extinction Ratio (ER), multicast signals can be delivered to designated subscribers with acceptable performance. At Optical Network Unit (ONU) side, upstream data can be remodulated on the downstream wavelength by a Reflective Semiconductor Optical Amplifier (RSOA), which is configured in the ONU. Combining low ER multicast ON/OFF signal with gain saturation effects of RSOA, good Bit Error Rate (BER) performance can be achieved for upstream data. Numerical results also demonstrate that when low ER is used for 2.5 Gbit/s downstream signal. BER performance will be improved for both upstream and downstream data.