Paramagnetic germanium-related centers induced by energetic radiation in optical fibers and preforms

Origlio, G.; Girard, Sylvain; Cannas, Marco; Ouerdane, Y.; Boscaino, R.; Boukenter, Aziz

doi:10.1016/j.jnoncrysol.2008.11.033

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…The defects are considered to be principally located in the region delimited by a radius of ~21 µm around the core center (zones 3 and 4). This assumption is justified by the fact that in [30] the absorption spectra show that a 4.5 eV peaked band attributed to Ge(1) [14,[16][17][18] is more evident in zones 3 and 4. For the Ge(2) such hypothesis is supported by the following considerations.…”

Section: Resultsmentioning

confidence: 99%

Evolution of Photo-induced defects in Ge-doped fiber/preform: influence of the drawing

Alessi¹,

Girard²,

Cannas³

et al. 2011

Opt. Express

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Abstract:We have studied the generation mechanisms of two different radiation-induced point defects, the Ge(1) and Ge(2) centers, in a germanosilicate fiber and in its original preform. The samples have been investigated before and after X-ray irradiation using the confocal microscopy luminescence and the electron paramagnetic resonance techniques. Our experimental results show the higher radiation sensitivity of the fiber as compared to the perform and suggest a relation between Ge(1) and Ge(2) generation. To explain our data we have used different models, finding that the destruction probability of the Ge(1) and Ge(2) defects is larger in fiber than in preform, whereas the generation one is similar. Finally we found that the higher radiation sensitivity of the fiber at low doses is essentially related to the presence of germanium lone pair center generated by the drawing. ©2011 Optical Society of America

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Section: Resultsmentioning

confidence: 99%

Evolution of Photo-induced defects in Ge-doped fiber/preform: influence of the drawing

Alessi¹,

Girard²,

Cannas³

et al. 2011

Opt. Express

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View full text Add to dashboard Cite

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Formation and conversion of defect centers in low water peak single mode optical fiber induced by gamma rays irradiation

Wen

Luo

Xiao

et al. 2010

Journal of Applied Physics

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The formation and conversion processes of defect centers in low water peak single mode optical (LWPSM) fiber irradiated with gamma rays were investigated at room temperature using electron spin resonance. Germanium electron center (GEC) and self-trapped hole center (STH) occur when the fibers are irradiated with 1 and 5 kGy cumulative doses, respectively. With the increase in irradiation doses, the GEC defect centers disappear, and new defect centers such as E′ centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate. The generation of GEC and STH is attributed to the electron transfer, which is completely balanced. This is the main reason that radiation-induced attenuation (RIA) of the LWPSM fiber is only 10 dB/km at communication window. The new defect centers come from the conversion of GEC and STH to E′ centers and NBOHC, and the conversion processes cause bond cleavage, which is the root cause that the RIA of the LWPSM fiber significantly increases up to 180 dB/km at working window. Furthermore, the concentration of new defect centers is saturated easily even by increasing cumulative doses.

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Transient Radiation Responses of Optical Fibers: Influence of MCVD Process Parameters

Girard

Marcandella

Alessi

et al. 2012

IEEE Trans. Nucl. Sci.

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International audienceA dedicated set of fibers elaborated via the Modified Chemical Vapor Deposition (MCVD) technique is used to study the influence of composition and drawing parameters on their responses to an X-ray pulse representative of the radiation environments associated with Megajoule class lasers. These canonical fibers were designed to highlight the impact of these parameters on the amplitude and kinetics of the transient pulsed X-ray Radiation Induced Attenuation (RIA) at room temperature. From preforms differing by their core composition, three optical fibers were elaborated by varying the tension and speed during the drawing process. No or only slight RIA change results from the tested variations in drawing process parameters of Ge-doped, F-doped, and pure-silica-core fibers. This study reveals that the drawing process is not the main parameter to be optimized in order to enhance the radiation tolerance of MCVD specialty optical fibers for the LMJ harsh environment. From the hardness assurance point of view, a specialty fiber sufficiently tolerant to this environment should be robust against changes in the drawing process. The origins of the RIA observed in the different fibers are discussed on the basis of spectral decomposition of their measured RIA spectra, using sets of defects from the literature and related to the different core dopants. This analysis highlights the limits of the well-known defect set to reproduce the RIA above 1 $mu{rm m}$ for Ge-doped fibers whereas self-trapped holes and chlorine-related species seem responsible for the transient responses of pure-silica-core and F-doped fibers

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Paramagnetic germanium-related centers induced by energetic radiation in optical fibers and preforms

Cited by 4 publications

References 16 publications

Evolution of Photo-induced defects in Ge-doped fiber/preform: influence of the drawing

Evolution of Photo-induced defects in Ge-doped fiber/preform: influence of the drawing

Formation and conversion of defect centers in low water peak single mode optical fiber induced by gamma rays irradiation

Transient Radiation Responses of Optical Fibers: Influence of MCVD Process Parameters

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