Photonic Generation of Ultrawideband (UWB) Pulse With Tunable Notch-Band Behavior

A photonic approach to generating the ultrawideband (UWB) pulses with tunable band-rejection behavior based on a negative coefficient two-tap microwave photonic filter is proposed and experimentally demonstrated. To avoid the interference between UWB and the Wireless Fidelity system, the UWB pulse with the “batwing” shape, which corresponds to the 5-GHz notch-band in frequency domain, is generated. Moreover, the band-notched position of the generated UWB signals could be tuned by adjusting the basic delay of the microwave photonic filter. Utilizing the optically tunable band-rejection character, the UWB systems can coexist with existing and future wireless network technologies almost without interference, as well as provide the opportunity for the combination between UWB-over-fiber and cognitive radio.