UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:34
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Conference: Bucharest University Faculty of Physics 2016 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Gamma radiation effects on electric arc discharge produced long period gratings


Authors:
A. STANCALIE(1), D SPOREA(1), D. NEGUT(2), Rajeev RANJAN(3) ,Flavio ESPOSITO (3), Agostino IADICICCO (3) and Stefania CAMPOPIANO (3)


Affiliation:
1)National Institute Laser, Plasma and Radiation Physics, 409 Atomiştilor St., Măgurele, RO-077125, Romania

2)Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering, Magurele, Romania

3)University of Naples “Parthenope” Centro Direzionale di Napoli Isola C4 80143 Naples, Italy


E-mail
andrei.stancalie@inflpr.ro


Keywords:


Abstract:
Radiation induced effects over optical fibers and optical fiber sensors [1, 2] have been subject of different studies in order to assess degradation and changes in the behavior of the gratings sensitivity both with absorbed dose and temperature. Depending on the fabrication of the fibers differences in the refractive index changes for the core, cladding or both may occur. We report the on-line investigation of different long period gratings (LPFGs) fabricated in Fluorine-doped cladding optical fibers by Electric Arc Discharge technique [3] as this type of fiber is less sensitive to radiation when compared to standard Ge-doped core ones. Experiments took place at an industrial irradiator based on 60Co gamma source and on-line investigations were carried using a Micron Optics SM125 Optical Interrogator in parallel with a 0.02 nm spectral resolution OFDR from by Luna Inc. Corrections were made as temperature was constantly monitored with a 0.1 oC resolution J-type thermocouple. Gratings response was monitored in consideration with the central wavelength shift and radiation induced attenuation (RIA) over a total dose of 34.9 kGy with an average dose rate of 0.18 kGy/h. As the gratings were written in optical fibers from different manufacturers, the spectral shift of the central wavelength for the LPFGs in “Nufern” fiber was noticed to be the most obvious one as it exceeded 6 nm compared with the LPFG written in “OZ-optics” single mode fiber (SMF), where saturation occurred before a 4 nm spectral shift. Temperature sensitivity of the gratings was evaluated before and after irradiation. Some recovery effects were noticed between irradiation stages, at room temperature and after heating cycles.


References:

[1] Rego, G., Fernandez, A.F., Gusarov, A., et al. 'Effect of ionizing radiation on the properties of arc-induced long-period fiber gratings', Applied Optics, 2005, 44, (29), pp. 6258–6263

[2] Sporea, D., Stӑncalie, A., Neguţ, D., Delepine-Lesoille, S., Lablonde, L.:’Long period grating response to gamma radiation’, Proc. SPIE 9886, Micro-Structured and Specialty Optical Fibres IV, 98861P (April 27, 2016)

[3] Ranjan, R., Esposito, F., Iadicicco, A., et al.: 'Comparative Study of Long Period Gratings Written in Standard and Fluorine-Doped Fibers by Electric Arc Discharge', IEEE Sensors J., 2016, 16, (11), pp. 4265–4273

Acknowledgement:
The Romanian authors acknowledge the support of the Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI), under Grant 8/2012, project “Sensor Systems for Secure Operation of Critical Installations”.