  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 stimulated Brillouin scattering (SBS) to achieve the
frequency-to-time mapping of microwave signals and the final STFT. By comparing
the experimental 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 more regular, and the frequency of the SUT measured in each
frequency-sweep period is more accurate. The mean absolute error is reduced by
50% under the optimal filter bandwidth.
