Open AccessSpectral characteristics and bend response of Bragg gratings inscribed in all-solid bandgap fibers
Author(s) -
Long Jin,
Zhi Wang,
Qiang Fang,
Yange Liu,
Bo Liu,
Guiyun Kai,
Xinyong Dong
Publication year - 2007
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.15.015555
Subject(s) - optics , cladding (metalworking) , materials science , fiber bragg grating , refractive index , phosfos , long period fiber grating , core (optical fiber) , grating , photonic crystal fiber , optical fiber , band gap , optoelectronics , graded index fiber , fiber optic sensor , physics , metallurgy
In this paper, we investigate the spectral characteristics and bend response of fiber Bragg gratings (FBGs) in all-solid photonic bandgap fibers (PBGFs). We inscribe FBGs within the secondary bandgap by ultraviolet (UV) side illumination and observe the couplings to backward core mode, guided LP(01) and LP(11) supermodes and radiative LP(02) supermodes. The mechanisms of these resonant couplings in the FBG are described in detail. We demonstrate that only those supermodes with certain phase relationships and symmetric mode field profiles are responsible for the supermode resonances. When the fiber grating is bent, the guided supermode resonances become chirped as a result of the strain gradient over the fiber cross section. Meanwhile, the core resonance is enhanced, due to more energy of the core mode distributed in the cladding rods. The bend response is direction dependant owing to the nonuniform UV-induced average index raises and index modulation over the high-index rod lattice. .