Microwave photonic filtering is realised using a superstructured fibre Bragg grating. The time delay of the optical taps is precisely controlled by the grating characteristics and fibre dispersion. A bandpass response with a rejection level of >45 dB is achieved.
Gwandu, B. A. L., Zhang, W., Williams, J. A. R., Zhang, L., & Bennion, I. (2002). Microwave photonic filtering using Gaussian-profiled superstructured fibre Bragg grating and dispersive fibre. Electronics letters, 38(22), 1328-1330. https://doi.org/10.1049/el:20020900