Microwave frequency measurement using a finite impulse response system that incorporates Lorentzian profile-weighted optical taps

We propose an advanced photonic microwave processing scheme useful for the accurate measurement of incoming microwave signal frequency over a wide frequency bandwidth. Our scheme is based on a finite impulse response system using Lorentzian profile-weighted multiple optical wavelength taps. Unlike the conventional schemes based on two optical taps, our scheme allows for well-defined, linear mapping of the incoming microwave frequency onto the output electrical power utilizing a log scale. In order to verify the principle, an experimental demonstration was carried out by using a multiwavelength channel beam, which was produced by the combination of a broadband, continuous wave supercontinuum and a digital micromirror device-based spatial light modulator. An excellent frequency measuring performance over a range of 1-9 GHz was achieved.