Open AccessHelical long-period grating manufactured with a CO_2 laser on multicore fiber
Author(s) -
Xiang Shen,
Xiongwei Hu,
Lüyun Yang,
Nengli Dai,
Jianjun Wu,
Fangfang Zhang,
Jingang Peng,
Haiqing Li,
Jinyan Li
Publication year - 2017
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.25.010405
Subject(s) - long period fiber grating , materials science , optics , grating , cladding (metalworking) , extinction ratio , cladding mode , fiber bragg grating , refractive index , core (optical fiber) , laser , fiber optic sensor , fiber laser , optoelectronics , optical fiber , graded index fiber , wavelength , polarization maintaining optical fiber , physics , metallurgy
We have demonstrated a helical long-period grating (HLPG) manufactured from multicore fiber (MCF) combined with twist and CO 2 -laser heating technology. The MCF we used behaves as a kind of single mode fiber. The nineteen cores of MCF are distributed hexagonally which make the helical structure only exist in core area after heating and twisting. There are several strong couplings between the core and cladding modes at different wavelengths when the grating pitch was 900 µm. The extinction ratio of the main coupling reached 20 dB at 1550 nm. We have investigated the sensor characteristics of the HLPG. It is found that the grating presents clear sensitivity to refractive-index while exhibiting smaller cross-sensitivity to environmental temperature than conventional long-period gratings. The HLPG also shows great potential as a twist sensor, which has a sensitivity up to 0.198 nm/(rad/m) and can apply for measuring twist directions.