Open AccessMode converter based on the long-period fiber gratings written in the two-mode fiber
Author(s) -
Yunhe Zhao,
Yunqi Liu,
Liang Zhang,
Chenyi Zhang,
Jianxiang Wen,
Tingyun Wang
Publication year - 2016
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.24.006186
Subject(s) - long period fiber grating , optics , materials science , cladding mode , mode volume , coupled mode theory , optoelectronics , fiber bragg grating , optical fiber , fiber optic sensor , radiation mode , single mode optical fiber , plastic optical fiber , polarization maintaining optical fiber , wavelength , refractive index , physics
We demonstrate the fabrication of long-period fiber gratings (LPFGs) written in the two-mode fiber (TMF) by CO 2 laser. Both uniform and tilted LPFGs were fabricated to provide the light coupling between LP 01 mode and LP 11 mode with a coupling efficiency of more than 99%. The writing efficiency and the bandwidth of the LPFG mode converter can be adjusted by changing the tilt angle of the tilted TMF-LPFGs. The torsion sensitivity of conventional and tilted LPFG mode converters were measured to be 0.37 nm/(rad/m) and 0.50 nm/(rad/m), respectively. Two orthogonal vector modes (the HEeven 21and HEodd 21 modes) and corresponding orbital angular momentum state were successfully obtained at the resonance wavelength. The proposed LPFG mode converter could be used as not only a high efficiency wavelength tunable mode converter in the mode division multiplexing system but also a high sensitive torsion sensor in the field of optical sensing.