title: Tunable, nondispersive optical filter using photonic Hilbert transformation.
abstract: We propose and numerically demonstrate a new design concept for implementing nondispersive complementary (band-pass/band-reject) optical filters with a wide range of bandwidth tunability. The device consists of two photonic Hilbert transformers (PHTs) incorporated into a Michelson interferometer (MI). By controlling the central frequency of PHTs with respect to each other, both the central frequency and the spectral width of the rejection/pass bands of the filter are proved to be tunable. Bandwidth tuning from 260 MHz to 60 GHz is numerically demonstrated using two readily feasible fiber Bragg grating-based PHTs. The designed filter offers a high extinction ratio between the pass band and rejection band (>20  dB in the narrow-band filtering case) with a very sharp transition with a slope of 170  dB/GHz from rejection to pass band.
authors.forename: Hamed Pishvai
authors.initials: HP
authors.lastname: Bazargani
authors.forename: María del Rosario
authors.initials: Mdel R
authors.lastname: Fernández-Ruiz
authors.forename: José
authors.initials: J
authors.lastname: Azaña