Journal article
Guiding Properties of Silica/Air Hollow-Core Bragg Fibers
The guiding properties of realistic silica/air hollow-core Bragg fibers have been investigated by calculating the dispersion curves, the confinement loss spectrum and the field distribution of the guided modes through a full-vector modal solver based on the finite element method. In particular, the silica bridge influence on the fundamental mode has been analyzed, by comparing the properties of an ideal structure, without the silica nano-supports, and of two realistic fibers, with squared off and rounded air-holes.
Simulation results have demonstrated the presence of anti-crossing points in the dispersion curves, associated to the transition of the fundamental mode into a surface one. It has been shown that surface modes are responsible of the sharp loss peaks, also experimentally measured, which pollute the loss spectrum of the fundamental mode and of the higher-order ones.
Then, the influence on the guiding properties of each geometric characteristic in the hollow-core Bragg fiber cross-section has been deeply investigated, thus showing which parameter it is better to change in order to properly modify the loss values or its spectral behaviour. Moreover, in order to improve the loss properties of hollow-core Bragg fibers, the number of silica and air layers in the fiber cladding has been increased, and the layer thickness has been modified.
Results have shown that the first change is more effective for the loss reduction, while the second is useful for a spectral shift. Finally, among the different possible applications, the feasibility of a DNA bio-sensor based on a hollow-core Bragg fiber has been demonstrated.
Language: | English |
---|---|
Publisher: | IEEE |
Year: | 2008 |
Pages: | 1877-1884 |
ISSN: | 15582213 and 07338724 |
Types: | Journal article |
DOI: | 10.1109/JLT.2007.913692 |
ORCIDs: | Lægsgaard, Jesper |
Air guiding Biosensors Bragg fiber Bragg fibers DNA DNA biosensor Optical fiber devices Optical fiber dispersion Optical fiber sensors Optical fibers Photonic crystal fibers Polymers Refractive index SiO<sub>2</sub> Silicon compounds Surface contamination biological techniques confinement loss spectrum dispersion curves fiber cladding fiber sensor fibre optic sensors finite element analysis finite-element method full-vector modal solver fundamental mode guided modes guiding properties higher order modes hollow-core fiber hollow-core fibers loss spectrum molecular biophysics optical fibre cladding optical fibre dispersion optical fibre losses silica bridge silica-air fibers silicon compounds spectral line shift spectral shift surface mode