title: Band-selection filters with concatenated long-period gratings in few-mode fibers.
abstract: We demonstrate a novel device that comprises a pair of broadband and narrowband long-period gratings written in specially designed few-mode fibers to achieve in-fiber bandpass filtering. This device configuration opens the possibility of using long-period gratings for complex spectral shaping in a band-selection as opposed to the conventional band-rejection configuration. The devices are low loss (<0.5dB) as well as tunable over large spectral ranges (26 nm). We demonstrate, for the first time to our knowledge, that the unique dispersive properties of long-period gratings allow for constructing dispersion-free bandpass filters with arbitrarily sharp spectral profiles.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Ramachandran
authors.forename: Samir
authors.initials: S
authors.lastname: Ghalmi
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Wang
authors.forename: Man
authors.initials: M
authors.lastname: Yan