A new microwave photonic filter structure that can achieve a high <i>Q</i> factor, high stopband rejection, and high skirt selectivity bandpass filter response simultaneously is presented. It is based on reflecting the signal back into a single amplified optical recirculating delay line and comprises coherent summation of the multiple signals that constitute each tap and incoherent summation of the successive taps. This introduces a new class of filter operation and effectively enables the realization of a higher order bandpass filter characteristic in a very simple structure. Experimental results are presented that demonstrate a multiple-tap high-<i>Q</i> bandpass filter response that also displays high stopband rejection level and high skirt selectivity.
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