A photonic ultra-wideband pulse generator by employing two paralleled Mach-Zehnder modulators

A scheme to generate ultra-wideband (UWB) pulses is presented and demonstrated. The key characteristic is that two paralleled Mach-Zehnder modulators are employed. The two Mach-Zehnder modulators are biased at full point and null point, respectively. By adjusting time delay difference between the output optical pulses at two Mach-Zehnder modulators, the UWB pulses can be generated. Firstly, theoretical analysis of this method is done; then, we verify the approach by simulation with commercial software. The results show that three category UWB pulses can be obtained as follows: Gaussian doublet pulse, negative Gaussian monocycle pulse and positive Gaussian monocycle pulse. The RF spectrum fulfill Federal Communication Commission (FCC) requirement. (C) 2013 Elsevier GmbH. All rights reserved.