Journal of Computer and Communications, 2014, 2, 36-41
Published Online May 2014 in SciRes. http://www.scirp.org/journal/jcc
http://dx.doi.org/10.4236/jcc.2014.27006
How to cite this paper: Urban, F. (2014) Optimization of the Tilted Fibre Bragg Gratings for the Fibre Accelerometric Sensor.
Journal of Computer and Communications, 2, 36-41. http://dx.doi.org/10.4236/jcc.2014.27006
Optimization of the Tilted Fibre Bragg
Gratings for the Fibre Accelerometric Sensor
Frantisek Urban1,2
1Dept of Microelectronics, Brno University of Technology, FEEC, Brno, Czech Republic
2Network Group, s.r.o., Brno, Czech Republic
Email: f.urban@nwg.cz, urban90@proficomms.cz
Received January 2014
Copyright © 2014 by authors and Scientific Research Publishing Inc.
This work is licensed under the Creative Commons Attribution International License (CC BY).
http://creativecommons.org/licenses/by/4.0/
Abstract
The presentation shows the principle and construction of the fibre optic accelerometric sensor.
The sensor element is based on the use of the tilted fibre Bragg grating (TFBG) that is imprinted to
the bend insensitive single-mode telecommunication grade fibre. The fibre section with TFBG is
then coupled to the evaluation fibre circuit with the cladding-core mode conversion element that
provides the core re-coupling of the optical power injected by TFBG to the fibre cladding. The
cladding-core mode conversion efficiency is sensitive to the acceleration generated fibre bending.
It is shown that the sensitivity of the device depends on the rate of the main core reflection versus
cladding ghost reflection induced by the grating. The analysis of the core reflection power coupl-
ing on the angle of the grating tilt and the analysis of the cladding ghost reflection power coupling
on the angle of the grating tilt is presented and the optimal parameters of the tilt and refractive
index modulation are derived. The presentation gives the experimental results of the TFBG sensor
prepared according to the optimization process.
Keywords
Optical Fibre, Tilted Fibre Bragg Grating, Accelerometric Sensor, Cladding Modes, Reflected
Spectrum
1. Introduction
Fibre optic accelerometric sensors are one of the applications of the optical fibres where the tilted Bragg gratings
can find the utilization. The principle of the fibre optic accelerometric sensor with the tilted Bragg grating is
shown in the Figure 1.
The sensor element is based on the use of the tilted fibre Bragg grating (TFBG) that is imprinted to the bend
insensitive single-mode telecommunication grade fibre. The fibre section with TFBG is then coupled to the