Modulator non linearity influence on UWB signal performance over RoF link

The external modulation, in the optical links, allows us to transmit a great quantity of digital data. With the spectral efficient given by the 16-QAM modulation and the OFDM, near 1 Gb/s transmission link is possible to get in UWB (Ultra-Wide Band). The direct modulation laser seems to be preferred for the radio over fibre (RoF) home and radar applications, due to its simplicity, but the limit in frequency modulation introduced by the laser biased circuit are lower. After the study of the main noise influence of the RIN laser diode of an EML transmitter used in an UWB RoF Link [1], in this paper, we focus this work on the impact of the non-linear effect on the transmission of UWB data on Radio over Fibre with direct and external modulations. The co-simulation results of those two types of link are presented and compared one to the other in term of performances.