Incremental Phase Modulation in Single Drive Mach-Zehnder Modulator

In future 5G mobile networks the radio over fiber (RoF) links will gain wider application due to its simplicity, flexibility and elasticity. In these links single drive Mach-Zehnder modulators are used for intensity modulation. However, these modulators produce not only intensity modulation but also incremental phase modulation which is a challenging problem because that effects the signal transmission. The other challenging problem is caused by fiber dispersion. Therefore fading of the detected signal is obtained at specific fiber lengths. However, applying combined double intensity and phase detection the received signal variation is reduced significantly. The transmission of digital signals is also influenced by fiber dispersion causing pulse broadening and this way inter-symbol interference which limits the bit rate. In this paper the modulation and propagation problems and their effects on signal transmission quality are investigated achieving this way optimum solution.