Sensitivity Enhancement of Turn-Around-Point Long Period Gratings By Tuning Initial Coupling Condition

Author

Biswas, Priyanka ; Basumallick, Nandini ; Bandyopadhyay, Supriyo ; Dasgupta, Kankar ; Ghosh, A. ; Bandyopadhyay, Supriyo

Author_Institution

Fiber Opt. & Photonics Div., Council of Sci. & Ind. Res.-Central Glass & Ceramic Res. Inst., Kolkata, India

Volume

15

Issue

2

fYear

2015

fDate

Feb. 2015

Firstpage

1240

Lastpage

1245

Abstract

Long period grating (LPG) at turn-around-point (TAP) has been studied with a view to enumerate the dependence of sensitivity of a particular resonant mode at the TAP to surrounding refractive index on the initial coupling strength. It has been shown theoretically and also validated experimentally that sensitivity can be enhanced significantly by tailoring the coupling strength of the cladding mode at the resonant wavelength near the TAP. Sensitivity characteristics have been studied for surrounding refractive index in the range 1.335-1.360, which is of interest in the field of biosensors, where the sensitivity of conventional LPGs is relatively small. We could attain a sensitivity of ~1850 nm/RIU using a TAP-LPG with ~3-dB attenuation at resonance.

Keywords

claddings; diffraction gratings; optical couplers; optical sensors; optical tuning; refractive index measurement; LPG; TAP; biosensor; cladding mode; initial coupling strength; initial coupling tuning condition; particular resonant mode; refractive index sensor; turn-around-point long period grating; Attenuation; Couplings; Optical fiber sensors; Optical fiber theory; Refractive index; Sensitivity; Long period grating; Refractive index sensing; Turn-Around-Point; refractive index sensing; turn-around-point;

fLanguage

English

Journal_Title

Sensors Journal, IEEE

Publisher

ieee

ISSN

1530-437X

Type

jour

DOI

10.1109/JSEN.2014.2361166

Filename

6915695