Uniform fiber Bragg grating first- and second-order diffraction wavelength experimental characterization for strain-temperature discrimination

Embedded dual fiber Bragg grating sensor for temperature-load (strain) discrimination

“…Accurate measurement of strain and temperature requires distinguishing gratings response to thermal effect and strain effect. Several methods have been reported for strain and temperature discrimination [7][8][9][10].…”

Multiparameter Sensor Based on Single High-Order Fiber Bragg Grating Made With IR-Femtosecond Radiation in Single-Mode Fibers

“…In order to avoid the multifiber solution to multiparameter sensing problems, a variety of other alternatives have been used. Techniques to discriminate sensing parameters include double superposed grating structures with different [1], FBGs in fiber with dissimilar diameters [2], utilization of the second-order diffraction from a saturated first-order 1550 nm grating [3], FBGs in birefringent fibers [4], etc. These techniques were developed mainly for the particular case of strain and temperature discrimination.…”

“…To a large extent the multiparameter sensing techniques are restricted to two parameters due to the availability of Manuscript only two Bragg resonances where matrix inversion techniques to discriminate between the two parameters are then utilized [1]- [3]. The simplest device used for temperature-strain discrimination is a simple first-order grating designed for 1550 nm operation that uses the first diffraction order at 1550 nm and the second diffraction order at for parameter discrimination [3]. The diffracted order is defined by the Bragg resonance equation…”

In situ Strain and Temperature Monitoring of Adaptive Composite Materials

“…To overcome this cross sensitivity using only embedded optical fibers, a number of techniques have been proposed, most of them relying on the deconvolution of two simultaneous measurements. These methods include the dual-wavelength superimposed gratings (Xu et al, 1994), the use of first-and second-order diffraction grating wavelengths (Echevarria et al, 2001), FBGs in optical fibers with different dopants (Cavaleiro et al, 1999;Guan et al, 2000), hybrid Bragg grating/ long period gratings (Patrick et al, 1996), dual-diameter FBGs (James et al, 1996), FBGs combined with EDFAs (Jung et al, 1999), FBG/EFPI combined sensors (Zeng and Rao, 2001;Kang et al, 2003), FBGs in high-birefringence optical fibers (Ferreira et al, 2000), the employment of strain-free FBGs (Song et al, 1997;Guan et al, 2002), and a combination of FBGs of different 'type' (Shu et al, 2002;Frazao et al, 2003). The use of a strain-free reference grating turns out to be the most efficient way to discriminate strain and temperature.…”