Detection limit of etched fiber bragg grating sensors

Shivananju, Nanjunda B and Renilkumar, M and Prashanth, Gurusiddappa R and Asokan, Sundararajan and Varma, Manoj M (2013) Detection limit of etched fiber bragg grating sensors. In: Journal of Lightwave Technology, 31 (14). pp. 2441-2447.

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Abstract

While Fiber Bragg Grating (FBG) sensors have been extensively used for temperature and strain sensing, clad etched FBGs (EFBGs) have only recently been explored for refractive index sensing. Prior literature in EFBG based refractive index sensing predominantly deals with bulk refractometry only, where the Bragg wavelength shift of the sensor as a function of the bulk refractive index of the sample can be analytically modeled, unlike the situation for adsorption of molecular thin films on the sensor surface. We used a finite element model to calculate the Bragg wavelength change as a function of thickness and refractive index of the adsorbing molecular layer and compared the model with the real-time, in-situ measurement of electrostatic layer-by-layer (LbL) assembly of weak polyelectrolytes on the silica surface of EFBGs. We then used this model to calculate the layer thickness of LbL films and found them to be in agreement with literature. Further, we used this model to arrive at a realistic estimate of the limit of detection of EFBG sensors based on nominal measurement noise levels in current FBG interrogation systems and found that sufficiently thinned EFBGs can provide a competitive platform for real-time measurement of molecular interactions while simultaneously leveraging the high multiplexing capabilities of fiber optics.

Item Type:	Journal Article
Publication:	Journal of Lightwave Technology
Publisher:	IEEE-Inst Electrical Electronics Engineers Inc
Additional Information:	Copyright of this article belongs to IEEE-Inst Electrical Electronics Engineers Inc.
Keywords:	Etched Fiber Bragg Grating; Layer by Layer Assembly; Limit of Detection; Weak Polyelectrolytes
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	02 Sep 2013 06:33
Last Modified:	02 Sep 2013 06:33
URI:	http://eprints.iisc.ac.in/id/eprint/46957

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