title: Broadband terahertz fiber directional coupler.
abstract: We present the design of a short broadband fiber directional coupler for terahertz (THz) radiation and demonstrate a 3 dB coupler with a bandwidth of 0.6 THz centered at 1.4 THz. The broadband coupling is achieved by mechanically downdoping the cores of a dual-core photonic crystal fiber by microstructuring the cores. This is equivalent to chemical downdoping but is easier to realize experimentally.
authors.affiliation: Technical University of Denmark, DTU Fotonik, Department of Photonics Engineering, DK-2800 Kgs. Lyngby, Denmark. krini@fotonik.dtu.dk
authors.forename: Kristian
authors.initials: K
authors.lastname: Nielsen
authors.forename: Henrik K
authors.initials: HK
authors.lastname: Rasmussen
authors.forename: Peter Uhd
authors.initials: PU
authors.lastname: Jepsen
authors.forename: Ole
authors.initials: O
authors.lastname: Bang