title: THz-bandwidth photonic Hilbert transformers based on fiber Bragg gratings in transmission.
abstract: THz-bandwidth photonic Hilbert transformers (PHTs) are implemented for the first time, to the best of our knowledge, based on fiber Bragg grating (FBG) technology. To increase the practical bandwidth limitation of FBGs (typically <200  GHz), a superstructure based on two superimposed linearly-chirped FBGs operating in transmission has been employed. The use of a transmission FBG involves first a conversion of the non-minimum phase response of the PHT into a minimum-phase response by adding an anticipated instantaneous component to the desired system temporal impulse response. Using this methodology, a 3-THz-bandwidth integer PHT and a fractional (order 0.81) PHT are designed, fabricated, and successfully characterized.
authors.forename: María R
authors.initials: MR
authors.lastname: Fernández-Ruiz
authors.forename: Lixian
authors.initials: L
authors.lastname: Wang
authors.forename: Alejandro
authors.initials: A
authors.lastname: Carballar
authors.forename: Maurizio
authors.initials: M
authors.lastname: Burla
authors.forename: José
authors.initials: J
authors.lastname: Azaña
authors.forename: Sophie
authors.initials: S
authors.lastname: LaRochelle