Open AccessBandwidth-narrowed Bragg gratings inscribed in double-cladding fiber by femtosecond laser
Author(s) -
Jiawei Shi,
Yuhua Li,
Shuhui Liu,
Haiyan Wang,
Ningliang Liu,
Peixiang Lu
Publication year - 2011
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.19.001734
Subject(s) - materials science , optics , femtosecond , fiber bragg grating , phosfos , refractive index , fiber laser , full width at half maximum , optoelectronics , inscribed figure , cladding (metalworking) , bandwidth (computing) , laser , annealing (glass) , optical fiber , wavelength , graded index fiber , fiber optic sensor , physics , telecommunications , geometry , mathematics , computer science , metallurgy , composite material
Bragg gratings with the bandwidth(FWHM) narrowed up to 79 pm were inscribed in double-cladding fiber with femtosecond radiation and a phase mask followed by an annealing treatment. With the annealing temperature below a critical value, the bandwidth of Bragg gratings induced by Type I-IR and Type II-IR index change was narrowed without the reduction of reflectivity. The bandwidth narrowing is due to the profile transformation of the refractive index modulation caused by the annealing treatment. This mechanism was verified by comparing bandwidth narrowing processes of FBGs written with different power densities.