This study has presented the complete comparison non return to zero (NRZ) and return to zero (RZ) modulation techniques for upgrading long haul optical wireless communication systems. Electrical signal to noise ratio is measured. This tutorial will take you through every aspect of the design, from discussions of why certain parameters are chosen, to the significance of. In this study, we compare rz and nrz line encrypting across a 40-gigabit-per-second system. It discusses the impact of chromatic dispersion, encoding characteristics, and performance metrics like bit error rate and quality factor.