Polarity- and Shape-Switchable UWB Pulse Generation Based on a Photonic Microwave Delay-Line Filter With a Negative Tap Coefficient

A novel and simple scheme to implement a two- or three-tap photonic microwave filter with one negative coefficient for polarity- and shape-switchable ultrawideband (UWB) pulse generation is proposed and demonstrated. The entire system can be reconfigured as a two- or three-tap microwave delay-line filter with one negative coefficient realized by operating a balanced photodetector (BPD) as a single photodetector or a BPD for the generation of UWB monocycle or doublet pulses. The polarity of the generated UWB pulses can be switched by tuning the transmission axis of the arbitrary wave plate. The proposed scheme is experimentally demonstrated. Gaussian monocycle and doublet pulses with fractional bandwidths of about 174% and 141% are generated.