UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:14

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Conference: Bucharest University Faculty of Physics 2017 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Comparative evaluation of two Long Period Gratings under gamma-ray irradiation


Authors:
Andrei STANCALIE(1), Dan SPOREA(1), Daniel NEGUT(2), Flavio ESPOSITO(3), Rajeev RANJAN(3), Stefania CAMPOPIANO(3), Agostino IADICICCO(3)


*
Affiliation:
1)National Institute Laser, Plasma and Radiation Physics, Center for Advanced Laser Technologies (CETAL), 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:
optical fiber sensors,long period gratings, radiation effects


Abstract:
In this work we conducted experimental and theoretical investigation on gamma radiation sensitivity of two Long Period Gratings engraved in single mode optical fibers. The sensors were fabricated by electric arc discharge technique, at University of Naples “Parthenope” in two different optical fibers in order to better understand their behavior and radiation hardness as a function of core/cladding dopants. The first fiber has SiO2 doped core and pure SiO2 cladding while the second has pure SiO2 core and F-doped SiO2 cladding. Gamma irradiation was performed at the 60Co source of the IRASM facility, part of IFIN-HH, in Romania. The optical sensors were irradiated up to a total average absorbed dose of 38 kGy with a 0.2 kGy/h dose rate and the spectral changes were recorded in real time. Pre and post irradiation investigations were done also both at Parthenope University, Naples and INFLPR, CETAL, Romania, to establish the impact of gamma radiation over temperature sensitivity of LPGs or refractive index changes. For on-line measurements we utilized an optical interrogator while temperature compensation was possible with the use of thermocouples inserted in the setup. The optical fibers connecting the instrumentation to LPG samples were shielded during the irradiation, to avoid radiation degradation. As the experiments were run in a comparative manner by keeping the same conditions for both LPGs, the results indicated differences in their behavior. The F-doped LPG proved its radiation hardness with under 1 nm shift of the central wavelength while the second LPG showed high sensitivity with accumulated dose with changes of more than 5 nm in the peak’s wavelengths.


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 and contract 4N/2016 financed by the National Authority for Research and Innovation. The work of the Italian authors was supported by the University of Naples “Parthenope” through the “Bando di sostegno alla ricerca individuale per triennio 2015-2017, Annualità 2016”.