A Novel Photonic Microwave Filter With Infinite Impulse Response

A novel design of a photonic microwave filter with infinite impulse response is presented and demonstrated experimentally, ft overcomes the problems due to optical coherence. The design exhibits substantial flexibility, permitting easy and continuous tunability of the free spectral range. In particular, when a Mach-Zehnder modulator is used in the filter, the passband of the filter response can be changed to stopband and vice versa. The design also provides scope for cascading more stages. Theoretical analysis and measured results are presented, showing a very good match between them.