Effect of UV-induced birefringence on long-period-gratingcoupling characteristics

Duhem, O.; Douay, M.

doi:10.1049/el:20000329

Cited by 18 publications

(18 citation statements)

References 5 publications

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“…The light passes a shutter (1), a half-wave plate (2), Glan prism (3), 100× long working distance microscopic objective (4), and is then focused in the fiber core (6). Two three-dimensional (3-D) translation stages for alignment are mounted on top of the high-precision computer-controlled two-dimensional (2-D) stage (7). We use two chargecoupled device (CCD) cameras (8) with optical zooming system for alignment and on-line monitoring of the inscription process.…”

Section: Fabricationmentioning

confidence: 99%

“…First, that both blue and red wavelength shifts of both polarization states were measured. For the p-polarization state, there were shifts of −0.38 to +1.90 nm, which are equivalent to changes in index ranging from −4.1 × 10 −6 to +2.0 × 10 −5 , assuming that the core index is unchanged [7]. For the s-polarization state, the shifts ranged from −1.66 to +1.50 nm, which are equivalent to changes in refractive index from −1.5 × 10 −5 to +1.6 × 10 −5 .…”

Section: Fabricationmentioning

confidence: 99%

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Bending characteristics of fiber long-period gratings with cladding index modified by femtosecond laser

Allsop

Dubov

Martínez

et al. 2006

J. Lightwave Technol.

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Abstract-A femtosecond laser has been used to asymmetrically modify the cladding of fiber containing long-period gratings. Following modification, devices in single-mode fiber are shown to be capable of sensing the magnitude and direction of bending in one plane by producing blue and red wavelength shifts depending upon the orientation of the bend. The resulting curvature sensitivities were −1.62 and +3.82 nm · m. Devices have also been produced using an elliptical core fiber to study the effects of the cladding modification on the two polarization eigenstates. A cladding modification applied on the fast axis of the fiber is shown to affect the light in the fast axis much more significantly than the light in the orthogonal state; this behavior may ultimately lead to a sensor capable of detecting the direction of bending in two dimensions for applications in shape sensing.Index Terms-Curvature measurement, long-period fiber gratings, polarization dependence.

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Section: Fabricationmentioning

confidence: 99%

Section: Fabricationmentioning

confidence: 99%

Bending characteristics of fiber long-period gratings with cladding index modified by femtosecond laser

Allsop

Dubov

Martínez

et al. 2006

J. Lightwave Technol.

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“…The reflected laser light travels back through the WDM and a polarization controller (PC) to the LPG where the signal is partially attenuated due to the mode coupling between the fiber core and the cladding of the LPG. The PC is included in the system to minimize the polarization dependence of the LPG, which was induced by the UV exposure during the fabrication process in a non-polarization-maintaining fiber [15]. This polarization dependence may be eliminated by writing the grating on photosensitive PM-fiber.…”

Section: Principle Of Operationmentioning

confidence: 99%

Simultaneous Measurement of Strain and Temperature Using a Single Emission Line

Leandro

Ams

Lopez-Amo

et al. 2015

J. Lightwave Technol.

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-In this study, we present and demonstrate a novel sensor system for simultaneous measurement of strain and temperature through a unique combination of a long period grating and a fiber laser based on a fiber Bragg grating. In order to achieve this, a new erbium-doped fiber laser structure is created, showing an optical signal-to-noise ratio of 55 dB and a peak power measured on the optical spectrum analyzer between −5 and 0 dBm. The strain and the temperature information can be obtained by using a unique emission line through monitoring both the fiber laser wavelength shift and the change of the power level, both of which showing a clear linear behavior. Permanent

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“…The authors of [17] (and references contained therein) have demonstrated that in circularly symmetric fibre the UV-induced birefringence caused by the photoinscription anisotropy can have a non-negligible effect on the LPG phasematching condition. This suggests that the wavelength satisfying the phase-matching condition for the overlapping attenuation bands corresponding to the two orthogonal polarisation states would be different for LPGs recorded with different exposures, as seen here.…”

Section: Fabrciationmentioning

confidence: 99%

“…A few papers have been presented concerning LPGs written in asymmetric optical fibres [7,12], which have shown red/blue wavelength shifts depending on the way the fibre is bent. There can be an additional problem of birefringence when fabricating an LPG sensor in asymmetric optical fibres, leading to polarisation dependence [15][16][17][18][19][20]. On the other hand, this polarisation dependence of the LPG can be utilised for creating polarisation filters [19,20].…”

Section: Introductionmentioning

confidence: 99%

The spectral sensitivity of long-period gratings fabricated in elliptical core D-shaped optical fiber

et al. 2004

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Long period gratings (LPGs) were written into a D-shaped optical fibre, which has an elliptical core with a W-shaped refractive index profile. The LPG's attenuation bands were found to be sensitive to the polarisation of the interrogating light with a spectral separation of about 15nm between the two orthogonal polarisation states. In addition, two spectrally overlapping attenuation bands corresponding to orthogonal polarisation states were observed; modelling successfully reproduced this spectral feature. The spectral sensitivity of both orthogonal states was experimentally measured with respect to temperature, surrounding refractive index, and directional bending. These LPG devices produced blue and red wavelength shifts of the stop-bands due to bending in different directions. The measured spectral sensitivities to curvatures, d /dR, ranged from -3.56nm m to +6.51nm m. The results obtained with these LPGs suggest that this type of fibre may be useful as a shape/bend sensor. It was also demonstrated that the neighbouring bands could be used to discriminate between temperature and bending and that overlapping orthogonal polarisation attenuation bands can be used to minimise error associated with polarisation.

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Effect of UV-induced birefringence on long-period-gratingcoupling characteristics

Cited by 18 publications

References 5 publications

Bending characteristics of fiber long-period gratings with cladding index modified by femtosecond laser

Bending characteristics of fiber long-period gratings with cladding index modified by femtosecond laser

Simultaneous Measurement of Strain and Temperature Using a Single Emission Line

The spectral sensitivity of long-period gratings fabricated in elliptical core D-shaped optical fiber

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