STFT Based on Stabilized Period-One Nonlinear Laser Dynamics and Stimulated Brillouin Scattering

A microwave photonic short-time Fourier transform (STFT) system based on stabilized period-one (P1) nonlinear laser dynamics and stimulated Brillouin scattering (SBS) is proposed. By using an optoelectronic feedback loop, the frequency-sweep optical signal generated by the P1 nonlinear laser dynamics is stabilized, which is further used in conjunction with an optical bandpass filter implemented by SBS to achieve the frequency-to-time mapping of microwave signals and the final STFT. By comparing the results with and without optoelectronic feedback, it is found that the time-frequency diagram of the signal under test (SUT) obtained by STFT is clearer and smoother, and the frequency of the SUT measured in each frequency-sweep period is more accurate. The measurement error is reduced by around 50% under the optimal filter bandwidth.