Generation of UWB pulses using direct modulation of semiconductor laser and optical filtering

A new method to generate ultra-wideband (UWB) pulses based on direct modulation of laser and optical filtering is demonstrated. The intensity modulation and the frequency modulation of the directly modulated laser are combined by the optical filter, which performs a photonic electro-optical derivative operation. Gaussian driving pulses are used in order to generate monocycles for ultra-wideband systems. In association with laser power oscillation, doublet waveforms could also be obtained. Monocycle and doublet pulses are experimentally generated with fractional bandwidths of 139 and 105%, respectively.