Phase-Modulation-Based Microwave Photonic Bandpass Filter Using a Programmable-Induced Frequency Response

A new optical phase modulator microwave photonic filter that can realize a flat-top radio frequency (RF) bandpass filter with multiple taps and bipolar coefficients is presented. It is based on a spatial light modulator that induces a programmable phase-modulation to intensity-modulation frequency response in combination with an RF phase-modulated multiwavelength signal. It enables the realization of negative taps, and opens up regions for operating the bandpass filter to extremely high frequencies. Experimental results demonstrate a multiple tap flat-top microwave filter at 18.5 GHz. To our best knowledge, this is the first phase modulator-based microwave photonic structure that exhibits multiple taps together with an arbitrary flat-top response.