Chaotic ultra-wideband microwave signal generation utilizing an optical injection chaotic laser diode

The ideal ultra-wideband (UWB) microwave pulses that fully comply with the indoor spectrum mask governed by Federal Communications Commission (FCC Indoor Mask) are generated by using continuous-wave optical injection to a chaotic laser diode. We firstly simulate and demonstrate the photonic generation of the chaotic UWB signal according to the rate equations of laser diode with optical feedback and injection. The simulations display that the -10 dB bandwidth of UWB signal increases with the increases of optical injection strength, frequency detuning, linewidth enhancement factor and with the decrease of bias current of the slave laser, and the UWB signal central frequency changes in a range from 5 to 8 GHz. We further experimentally obtain tunable chaotic UWB microwave signals with a rate up to 500 Mbit/s by tuning optical injection strength when the other parameters are fixed. The experimental results are in accordance with the theoretical analyses.