Open AccessMultiple mode conversion and beam shaping with superimposed long period gratings
Author(s) -
M. Sumetsky,
Siddharth Ramachandran
Publication year - 2008
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.16.000402
Subject(s) - optics , beam (structure) , graded index fiber , materials science , fiber , mode volume , refractive index , optical fiber , single mode optical fiber , light beam , fiber bragg grating , long period fiber grating , fiber optic sensor , physics , composite material
We demonstrate how to convert several arbitrary optical fiber modes into a single mode and vice versa using superimposed long period gratings (SLPG). As an example, we theoretically consider SLPG consisting of five gratings, which couple first six LP(0j) modes of a single mode fiber. We optimize the SLPG output to form light beams that are focused at a distance 0.5 mm and 1 mm from the fiber. In addition, we optimize the SLPG output to generate a beam with an amplitude that is uniform inside a 4(0) angle with a +/-0.2 % accuracy. In the latter case, the refractive index profile of the SLPG is calculated for an SMF-28 fiber. The proposed SLPG devices can be used as efficient all-fiber mode focusers and beam shapers.