Compressive Sensing Detection of RF Signals by All-Optically Generated Binary Random Patterns

High-speed random bit sequences are crucially important in temporal compressive sensing applications. In this work, we propose a new all-optical binary random patterns generation method for compressive sensing, completely eliminating the use of high-speed electronic circuits. This approach uses photonic time stretched optical pulses as the optical carrier. Spectrum slicing using a tunable ring resonator produces a train of uniformly spaced optical pulses (bits) due to spectrum-to-time mapping in photonic time stretch. Two cascaded dispersive devices with particularly designed nonlinear dispersion profiles are employed to introduce random time delays among optical pulses, leading to a quasi-random binary sequence. The random sampling pulse sequence can be updated by changing the free-spectral range of the ring resonator. The proposed method is verified by numerical simulations. The photonic generated random pulse sequences are used in compressive sensing detection of high-frequency RF signals. In a proof-of-concept demonstration, one-tone and multi-tone microwave signals are successfully reconstructed from four-time compressed measurement data.