Coherent photonic processing of microwave signals using spatial light modulators: programmable amplitude filters

This paper presents a novel coherent optical signal processing approach for synthesis of programmable microwave amplitude filters over an ultrawideband. The authors´ scheme relies on a programmable hyperfine optical filter implemented in a pulse-shaping geometry, which provides arbitrary, user-defined amplitude-filtering functions over a 50-GHz bandwidth with resolution better than 0.7 GHz. In contrast to previous work on discrete time optical processing of microwave signals, their approach allows direct synthesis of microwave filter functions in spectral domain without computing filter coefficients, which is needed for a discrete-time-domain approach.