Slow and fast light effects in a tilted fiber Bragg grating and the application in a continuously tunable microwave photonic filter

Slow and fast light effects in a tilted fiber Bragg grating (TFBG) and the application in a tunable microwave photonic filter are studied. A TFBG has multiple cladding mode resonances. By optically pumping, the magnitude and group delay responses of the cladding mode resonances are changed, which are used to achieve a phase delay or advance. The use of a TFBG in a delay-line filter would lead to the tuning of the spectral response. A frequency-tunable microwave photonic filter is demonstrated.