Simulation and performance analysis of duobinary 40 Gbps optical link

This paper presents a system model to simulate and evaluate the performance of duobinary RZ (DB-RZ) and duobinary NRZ (DB-NRZ) modulation format in a 40 Gbps optical communication link. The design has been optimized to estimate the electrical and optical filter parameters for optimum performance under dispersion and self-phase modulation induced impairments. The presented model has been operated under various OSNR conditions to investigate the limitations of GVD and SPM on the BER-equivalent Q-factor for DB-NRZ and DB-RZ encoded optical data. The analysis reports the superiority of DB-NRZ over DB-RZ at higher OSNR. However, for a typical OSNR value a crossover optical filter bandwidth has been observed beyond which DB-RZ outperforms DB-NRZ.