Title :
Controlling the Sensitivity of Refractive Index Measurement Using a Tapered Fiber Loop Mirror
Author :
Zibaii, M.I. ; Frazão, O. ; Latifi, H. ; Jorge, P.A.S.
Author_Institution :
INESC Porto, Porto, Portugal
Abstract :
A single-mode nonadiabatic tapered optical fiber (NATOF) sensor was inserted into a fiber loop mirror (FLM) enabling us to tune its sensitivity towards refractive index (RI). The NATOF was fabricated by the heat pulling method, utilizing a CO2 laser. The adjustment of the polarization controllers (PCs) inserted in loop allowed us to excite different cladding modes in the interferometric taper resulting in different optical paths for the clockwise and the counterclockwise beams. By variation of the PCs´ settings, the sensitivity of the sensor for RI in the range from 1.3380 to 1.3510 could be tuned from 876.24 to 1233.07 nm/RIU. Experimental results show that the sensitivity to the external RI increased with the order of the cladding mode.
Keywords :
fibre optic sensors; light interferometry; mirrors; optical control; optical fibre cladding; optical fibre fabrication; optical fibre polarisation; optical tuning; refractive index measurement; cladding modes; counterclockwise beams; heat pulling method; interferometric taper; polarization controllers; refractive index measurement; sensitivity control; single-mode nonadiabatic tapered optical fiber sensor; tapered fiber loop mirror; Mirrors; Optical fiber couplers; Optical fiber polarization; Optical fiber sensors; Optical interferometry; Sensitivity; Fiber loop mirror (FLM); nonadiabatic taper; refractive index (RI);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2011.2158641
