A simple and low-cost spectrum sliced microwave
photonic filter with high tunability has been implemented. This is
based on use of two Fabry-Pérot filters with same free spectral
range connected in parallel but one filter with an external fiber
delay. An extension of this configuration with Fiber Bragg Grating
(FBG) as delay element is also demonstrated. This architecture
overcomes the tuning difficulties of a single Fabry-Pérot filter
employed as a slicing element. Flexible tunability, large overall free
spectral range and high quality factor have been obtained with the
proposed configuration owing to the use of fiber delay/FBG. Wide
and step tuning has been achieved in the frequency range of
41.1GHz to 50.23GHz in steps of 2.28GHz. The additional
components are another Fabry-Pérot filter and fiber delay/FBG
which makes the proposed architecture highly compact and costeffective.
Most of the practical difficulties faced in use of optical
fiber are eliminated using FBGs. The characteristics of proposed
configuration with different applied delays using fiber and FBG
were tabulated. An analysis of flexible tunable property of the filter
was made in terms of length of fiber delay and grating length of
FBG and the results were plotted. Also quality factor calculation of
the proposed filter was discussed.
