Broadband and precise microwave time reversal using a single linearly chirped fiber Bragg grating

We propose and experimentally demonstrate a novel technique to achieve broadband and precise microwave time reversal using a single linearly chirped fiber Bragg grating (LCFBG). In the proposed system, the time reversal is realized by the LCFBG that is operating in conjunction with a polarization beam splitter (PBS) to enable a triple use of the LCFBG with the signal entering the grating from either the long or the short wavelength end. Since the LCFBG has a wide bandwidth and is used three times with exactly complementary and identical dispersion, the implementation of broadband and precise microwave time reversal is ensured. A theoretical analysis is performed which is validated by an experiment. The time reversal of a 5-GHz microwave single with a bandwidth of 3.3 GHz and a time duration of about 0.7 ns is demonstrated, which is, to the best of our knowledge, the fastest microwave time reversing system ever reported.