title: Directional coupling in twin-core photonic bandgap fibers.
abstract: The frequency dependence of the coupling length in a twin-core photonic bandgap fiber is investigated numerically. In contrast to the case of index-guiding fibers, the coupling length exhibits a maximum if the cores are sufficiently well separated. The fiber design proposed is of interest for fabricating broadband tunable couplers.
authors.affiliation: Research Center COM, Technical University of Denmark, Building 345v, DK-2800 Kongens Lyngby. jl@com.dtu.dk
authors.forename: J
authors.initials: J
authors.lastname: Laegsgaard