Investigation of RZ and NRZ pulse shape for optimum Duobinary transmission at 40 Gbps

This paper reports a simulative investigation on the RZ and NRZ pulse shape for optimum optical duobinary transmission in amplified spontaneous emission (ASE)-noise-limited system at 40 Gbps. By deploying electrical low-pass filtering at the transmitter end and optical filtering at the receiver end, we achieved the desired duobinary pulse shape that provides optimum performance suppressing the ASE noise. Further analysis in the system with optimized filter parameters shows that NRZ duobinary provides better receiver sensitivity as compared to RZ duobinary in a channel limited by fiber chromatic dispersion.