Spectral recovery of broadband waveforms via cross-phase modulation based tunable Talbot amplifier

Physical processes in the Fourier domain play a crucial role in various applications such as spectroscopy, quantum technology, ranging, radio-astronomy, and telecommunications. However, the presence of stochastic noise poses a significant challenge in the detection of broadband spectral waveforms, especially those with limited power. In this study, we propose and experimentally demonstrate a cross-phase modulation (XPM) based spectral Talbot amplifier to recover the broadband spectral waveforms in high fidelity. Through the combination of spectral phase filtering and XPM nonlinear effect in an all-fiber configuration, we demonstrate spectral purification of THz-bandwidth spectral waveforms submerged in strong noise. The proposed spectral Talbot amplifier provides tunable amplification factors from 3 to 10, achieved by flexible control on the temporal waveform of the pump and the net dispersion. We demonstrate up to 10-dB remarkable improvement on optical signal-to-noise ratio (OSNR) while preserving the spectral envelope. Furthermore, our system allows frequency-selective reconstruction of noisy input spectra, introducing a new level of flexibility for spectral recovery and information extraction. We also evaluate numerically the impact of pump intensity deviation on the reconstructed spectral waveforms. Our all-optical approach presents a powerful means for effective recovery of broadband spectral waveforms, enabling information extraction from a noise-buried background.