Open AccessSensitive refractive index sensor based on an assembly-free fiber multi-mode interferometer fabricated by femtosecond laser
Author(s) -
Pengcheng Chen,
Xuewen Shu,
Fangcheng Shen,
Haoran Cao
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.25.029896
Subject(s) - materials science , femtosecond , optics , interferometry , refractive index , laser , fiber optic sensor , photonic crystal fiber , normalized frequency (unit) , optical fiber , graded index fiber , optoelectronics , wavelength , physics , phase locked loop , frequency synthesizer , phase noise
We propose and demonstrate a highly sensitive refractive index (RI) sensor based on a novel fiber-optic multi-mode interferometer (MMI), which is formed with a femtosecond-laser-induced in-core negative refractive index modified line in a standard single mode fiber. The proposed MMI structure is directly written with femtosecond laser in one step, which removes the splicing process needed in conventional MMI fabrication and also significantly improves the robustness. This device exhibits a high sensitivity to surrounding refractive index, with a maximum sensitivity up to 10675.9 nm/RIU at the RI range of 1.4484-1.4513. The distinct advantages of high sensitivity, compact, robust and assembly-free all-fiber structure make it attractive for real physical, chemical and biological sensing.