Reconfigurable Generation of High-Order Ultra-Wideband Waveforms Using Edge Detection

The generation of ultra-wideband (UWB), high-frequency waveforms based on nonlinear propagation of pulses in optical fibers is reported. Self-phase modulation and subsequent optical filtering are used to implement all-optical edge detectors, which generate two temporally-narrowed replicas of each input pulse. The shapes of the narrowed pulses are subtracted from that of the original one in a balanced differential detector, providing a UWB waveform. The use of multiple replicas and nonlinear propagation allows for the generation of higher-order pulse shapes, beyond those of a Gaussian monocycle or doublet. The output pulse shape is reconfigurable through adjusting the input power and detuning the optical filters. The central radio-frequency of the generated waveforms is as high as 34 GHz, with a fractional bandwidth of 70%.