Programmable broadband radio-frequency transversal filter with compact fiber-optics and digital microelectromechanical system-based optical spectral control

To the best of our knowledge, for the first time a programmable broadband rf transversal filter is proposed that operates on the principle of broadband optical spectral control implemented with a spatial light modulator input rf signal time delay and weight selection over a near-continuous signal space. Specifically, the filter uses a chirped fiber Bragg grating in combination with a two-dimensional digital micromirror device to enable a programmable rf filter. As a first step, a two-tap rf notch filter is demonstrated with a tuning range of 0.563-6.032 GHz with a 25-dB notch depth at test notch frequencies of 845 and 905 MHz. The proposed filter can find applications in diverse fields such as radar, communications, medicine, and test and measurement.