High-speed ultrawideband photonically enabled compressed sensing of sparse radio frequency signals

Abstract

We demonstrate a new architecture for high-speed compressed sensing using chirp processing with ultrafast laser pulses, presently applied to the measurement of sparse-frequency microwave signals. We spectrally encode highly chirped ultrafast laser pulses with pseudorandom bit sequences such that every laser pulse acquires a unique spectral pattern. The pulses are partially compressed in time, extending the effective sampling rate beyond the electronic limit, and then modulated with a sparse microwave signal. Finally the pulses are fully compressed and detected, effectively integrating the measurement. We achieve 100 usable features per pattern allowing for 100 points in the reconstructed microwave spectra and experimentally demonstrate reconstruction of two- and three-tone microwave signals spanning from 900 MHz to 14.76 GHz. These spectra are reconstructed by measuring the energy of only 23 to 38 consecutive laser pulses acquired in a single shot with a 500 MHz real-time oscilloscope.