A UWB over fiber system based on frequency-dependent gain saturation in a RSOA

A novel UWB over fiber system based on the frequency-dependent gain saturation in a reflective semiconductor optical amplifier (RSOA) is proposed and experimentally demonstrated. Because the gain saturation in the RSOA is more evident when the injected optical signal has a lower modulation frequency, the RSOA operated at the gain saturation regime can shape a dark or bright Gaussian pulse to a UWB pulse. The generated UWB signals with an on-off keying format are transmitted in a single mode fiber and a wireless link. The power penalty is less than 1.2 dB. Since the RSOA is possibly a key device in WDM-PONs, the proposed optical UWB over fiber system can be used to provide UWB services in a WDM-PON system without increasing significantly the cost.