Proposal and realization for a broadband all-fiber non-uniformly spaced multi-channel optical filter

In this paper, we propose a broadband all-fiber non-uniformly spaced multi-channel optical filter, which is based on the utilization of paired multi-channel fiber Bragg gratings (FBGs) located at two arms of an interferometer. Unlike the traditional optical comb filter, the channel spacing may be either linearly or nonlinearly chirped. Serving as an example, two identical linearly-chirped 51-channel FBGs have been successfully employed to demonstrate the proposed filter experimentally.