Comparative analysis and power optimization for return to zero and non return to zero coded transmission in 40 Gbps fiber optics system

Abstract

The input launch power of an optical source is a very important factor for communication engineers in designing fiber optics communication systems. By increasing the input launch power, the non linear effects like Four wave mixing (FWM), Cross phase modulation (XPM) and Self phase modulation (SFM) also affect the BER (bit error rate) by decreasing the maximum Q. factor (Quality factor). In this work a comparative analysis for RZ (return to zero) and NRZ (non return to zero) coded transmission has been shown through simulation results for 40 Gbps fiber optic system at fiber lengths (100–300) km using standard single mode fiber (SMF) in Optisystem software. It has been shown that RZ coded modulation can tolerate more distortion and reach longer transmission distance as compared to NRZ coded modulation. Also, Input launch power has been optimized for RZ and NRZ coded transmission in order to achieve more fruitful and reliable transmission.