Tuneable high-Q microwave photonic bandpass filter without coherent interference limitations

A new tuneable high-resolution microwave photonic bandpass filter without coherent interference limitations, is presented. It is based on a wavelength dependent delay line incorporated into a frequency shifting amplified recirculating delay line structure. The tuning operation is obtained by changing the optical source wavelength, which alters the delay line loop length. Experimental results are presented for the novel structure, which demonstrate tuneable high-resolution microwave photonic bandpass filtering with a Q of 150, and with no coherence and phase-induced intensity noise limitations.