Open AccessA methode of estimating the reflectivity and refractive-index modulation of double-cladding large core fiber Bragg grating
Author(s) -
Zhou Ren-Lai,
Ju You-Lun,
Yang Chao,
Wei Wang,
Yuezhu Wang
Publication year - 2012
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.61.244205
Subject(s) - materials science , optics , cladding (metalworking) , fiber bragg grating , step index profile , refractive index , graded index fiber , core (optical fiber) , femtosecond , grating , phosfos , laser , long period fiber grating , optical fiber , optoelectronics , fiber optic sensor , physics , metallurgy
A simple and practical method of estimating reflectivity and refractive-index modulation is reported when writing fiber Bragg grating (FBG) into silica fiber core based on 800 nm femtosecond laser pulses and a phase mask. By monitoring and recording the variation of the fiber laser output power, the reflectivity and refractive-index modulation are estimated theoretically and experimentally. The reflectivity of FBG is approximate 96.4%, and the refractive-index modulation is about 1.2×10-3. When the FBG is used as a linear cavity mirror, 15.5 W of output power is obtained under an incident pump power of 51.6 W, corresponding to a slop efficiency of 37.9%. A beam factor of M2=1.4 at an output power of 15 W is measured by using the knife-edge method.