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

Abstract

Abstract-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%.

M-ary energy detection of a Gaussian FSK UWB system

“…In [18], the pulse generator arrives to the 13th order. The pulse generator in [19] can generate the pulse with a center frequency at 34 GHz. The higher the order of the pulse is, the higher the center frequency is.…”

Ultra-Wideband Waveform Generation Using Nonlinear Propagation in Optical Fibers

“…The generation of UWB pulses was demonstrated experimentally, using the setup of Fig. 3 (Zadok et al, 2010b. The parameters of the input pulse train and HNLF, and the settings of the BPFs, VOAs and TDLs were the same as those of the previous sections.…”

“…UWB impulse radio generation using self-phase modulation in optical fibers 2.1 Self-phase modulation based edge detection Consider the optical field ( ) in Et of an input train of super-Gaussian pulses (Zadok et al, 2010b () ( ) at the output of two 75 GHz-wide BPFs, whose central frequencies are detuned from 0 ω by 2 ± Δωπ = ± 135 GHz, respectively. As expected, the filtered waveforms emphasize the pulse edges, and both are narrower than the original input pulse.…”

“…The shape of the two narrowed replicas can be subtracted from that of the original pulse to generate an UWB waveform, as described next. Figure 3 shows a schematic drawing of a setup for UWB waveform generation, based on alloptical edge detection (Zadok et al, 2010b. The input super-Gaussian pulse train is split in two branches.…”

“…2009; Zadok et al, 2010a, 2010b. All-optical edge detectors of the input pulses intensity are used to generate two temporally-narrowed replicas of the input pulse train.…”