Abstract: In this paper, a novel method to generate ultrawideband (UWB) doublets is
proposed and experimentally demonstrated, which is based on exploiting the cross-phase
modulation in a semiconductor optical amplifier (SOA). The key component is an integrated
SOA Mach–Zehnder interferometer pumped with an optical carrier modulated by a
Gaussian pulse. The transfer function of the nonlinear conversion process leads to the
generation of UWB doublet pulses by tuning the SOA currents to different values.
Index Terms: Interferometric structure, nonlinear optics, microwave photonics, fiber optics,
optical communications.