title: Tuning properties of long period gratings in photonic bandgap fibers.
abstract: We investigate the thermal tuning properties of long period gratings (LPGs) in a fluid-filled photonic bandgap fiber (PBGF). The combination of strong, resonant waveguide dispersion, characteristic of all PBGF modes, and the large thermo-optic coefficients of fluids yields highly tunable grating resonances. We measure grating resonances in three transmission bands with large tuning coefficients of up to -1.58 nm/degrees C, which match numerical results. We derive an analytic model for the PBGF LPG tuning coefficient to show how it depends on both the shift of the transmission bands and the dispersion of the coupled modes.
authors.affiliation: Centre for Ultrahigh-bandwidth Devices for Optical Systems (CUDOS), School of Physics, University of Sydney, New South Wales, Australia. pes.physics.usyd.edu.au
authors.forename: P
authors.initials: P
authors.lastname: Steinvurzel
authors.forename: E D
authors.initials: ED
authors.lastname: Moore
authors.forename: E C
authors.initials: EC
authors.lastname: Mägi
authors.forename: B J
authors.initials: BJ
authors.lastname: Eggleton