Photonic Generation of 3-D UWB Signal Using a Dual-Drive Mach-Zehnder Modulator

We propose and experimentally demonstrate a new method to generate a 3-D ultrawideband (UWB) signal by utilizing a dual-drive Mach-Zehnder modulator (DDMZM). Three degrees of freedom of the generated 3-D UWB signal are pulse position, pulse phase, and pulse amplitude. In this scheme, each radio frequency (RF) port of the DDMZM is modulated by a combination of two encoded signals with different amplitudes. By properly adjusting the amplitudes of the encoded signals and the bias voltages of the two RF ports, a 5-Gb/s 3-D UWB signal with a central frequency of 3.5 GHz and a 10-dB fractional bandwidth of 163% is successfully generated by using only a single DDMZM.