posted on 2021-05-23, 12:16authored byYonas Endailalu
Two integrating techniques and topologies for fiber optic network systems such as RoF and FTTH have been studied and presented in this project. Two digital signals with data rate 622Mb/s and 1.25Gb/s are considered as the two service signals to be hybrid. Both signals are first modulated in electrical domain by 25GHz and 5GHz sinusoidal
sub carriers respectively, in order to give them enough spectral separation. Two architectures have been studied to modulate the optical carrier with these two service signals. The first model is to sum the two service signals in the electric domain and use a single leg Mach Zender Modulator (JlvlZM) to modulate the optical carrier with the electrical message signal. In the second case, the two service signals are first sent to a two leg MZM and separately modulate the light wave carrier, then the two emerging light wave signals mix at the other end of the Y branch of the MZM. The mathematical equations that represent the function of the two kinds of MZM have been formulated. Simulations of the integration of the two hybrid services have been made in MATLAB-Simulink environment and the results are shown. The developed mathematical models are used to represent the MZMs in the MATLAB program. Detector models for each architecture have been developed in order to evaluated the SNR and compare performance using Bit Error Rate (BER). The BER plots for different input setup have been plotted and presented in this project.