Discrimination of strain and temperature using Bragg gratings in microstructured and standard optical fibres

In this work two sensing heads based on fibre Bragg grating structures are demonstrated, one for temperature independent measurement of strain and the other for simultaneous measurement of these two parameters. The first one relies on a single Bragg grating inscription in a microstructured optical fibre, resulting for two input orthogonal polarizations in two distinct resonance peaks with similar temperature sensitivities and different strain sensitivities. In the second structure two gratings were considered, one written in the same microstructured fibre and the other on a standard SMF fibre. Considerably different strain and temperature sensitivities were obtained for these two gratings, enabling simultaneous temperature and strain measurement with resolutions of ±1.5 °C and ±10.7 µe over a measurement range of 100 °C and 2000 µe, respectively.

[1]  A. Kersey,et al.  High-resolution fibre-grating based strain sensor with interferometric wavelength-shift detection , 1992 .

[2]  W. Michie,et al.  Simultaneous measurement of strain and temperature: error analysis , 1997 .

[3]  D. Richardson,et al.  Nonlinearity in holey optical fibers: measurement and future opportunities. , 1999, Optics letters.

[4]  Brian Joseph Mangan,et al.  Two-dimensional bend sensing with a single, multi-core optical fibre , 2000 .

[5]  Faramarz Farahi,et al.  Simultaneous measurement of strain and temperature using interferometrically interrogated fiber Bragg grating sensors , 2000 .

[6]  B. Eggleton,et al.  Microstructured optical fiber devices. , 2001, Optics express.

[7]  David J. Richardson,et al.  Sensing with microstructured optical fibres , 2001 .

[8]  Niels Asger Mortensen,et al.  Effective area of photonic crystal fibers. , 2002, Optics express.

[9]  H. Thienpont,et al.  Sensitivity of holey fiber based sensors , 2003, Proceedings of 2003 5th International Conference on Transparent Optical Networks, 2003..

[10]  David J. Webb,et al.  Temperature insensitive long-period grating sensors in photonic crystal fibre , 2004 .

[11]  John M. Fini,et al.  Microstructure fibres for optical sensing in gases and liquids , 2004 .

[12]  Henrique M. Salgado,et al.  Low-Loss Splice in a Microstructured Fibre Using a Conventional Fusion Splicer , 2005 .

[13]  John Canning,et al.  Bragg gratings in photonic crystal fibers: strain and temperature chacterization , 2005, International Conference on Optical Fibre Sensors.

[14]  Orlando Frazão,et al.  Applications of Fiber Optic Grating Technology to Multi-Parameter Measurement , 2005 .