Open AccessCapturing reflected cladding modes from a fiber Bragg grating with a double-clad fiber coupler
Author(s) -
Mohamad Diaa Baiad,
Mathieu Gagné,
Simon Lemire-Renaud,
Étienne De Montigny,
WendyJulie Madore,
Nicolas Godbout,
Caroline Boudoux,
Raman Kashyap
Publication year - 2013
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.21.006873
Subject(s) - cladding (metalworking) , fiber bragg grating , materials science , optics , cladding mode , long period fiber grating , tapering , refractive index , grating , optical fiber , photonic crystal fiber , plastic optical fiber , graded index fiber , single mode optical fiber , double clad fiber , polarization maintaining optical fiber , optoelectronics , fiber optic sensor , physics , composite material , computer science , computer graphics (images)
We present a novel measurement scheme using a double-clad fiber coupler (DCFC) and a fiber Bragg grating (FBG) to resolve cladding modes. Direct measurement of the optical spectra and power in the cladding modes is obtained through the use of a specially designed DCFC spliced to a highly reflective FBG written into slightly etched standard photosensitive single mode fiber to match the inner cladding diameter of the DCFC. The DCFC is made by tapering and fusing two double-clad fibers (DCF) together. The device is capable of capturing backward propagating low and high order cladding modes simply and efficiently. Also, we demonstrate the capability of such a device to measure the surrounding refractive index (SRI) with an extremely high sensitivity of 69.769 ± 0.035 μW/RIU and a resolution of 1.433 × 10(-5) ± 8 × 10(-9) RIU between 1.37 and 1.45 RIU. The device provides a large SRI operating range from 1.30 to 1.45 RIU with sufficient discrimination for all individual captured cladding modes. The proposed scheme can be adapted to many different types of bend, temperature, refractive index and other evanescent wave based sensors.