High-order infinite impulse response microwave photonic filters

Two new high-order infinite impulse response microwave photonic filters, which have multiple poles and zeros in the transfer characteristic, are presented. They are based on either the wavelength division multiplexing technique with a single infinite impulse response delay line structure or a single laser with multiple infinite impulse response delay line structures. A wavelength converter is used to increase the filter order without the coherent interference problem. A high-resolution and high-performance bandpass filter response can be realized. Experimental results are presented that demonstrate high-resolution bandpass filter responses with robust operation, and high stopband rejection level and high skirt selectivity.