scholarly journals Radiation Effects on Pure-Silica Multimode Optical Fibers in the Visible and Near-Infrared Domains: Influence of OH Groups

2021 ◽  
Vol 11 (7) ◽  
pp. 2991
Author(s):  
Cosimo Campanella ◽  
Vincenzo De Michele ◽  
Adriana Morana ◽  
Gilles Mélin ◽  
Thierry Robin ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Radiation Effects ◽  
Near Infrared ◽  
Signal Transmission ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Pure Silica ◽  
Oxygen Hole ◽  
Three Samples ◽  
Radiation Induced

Signal transmission over optical fibers in the ultraviolet to near-infrared domains remains very challenging due to their high intrinsic losses. In radiation-rich environments, this is made even more difficult due to the radiation-induced attenuation (RIA) phenomenon. We investigated here how the number of hydroxyl groups (OH) present in multi-mode (MM) pure-silica core (PSC) optical fibers influences the RIA levels and kinetics. For this, we tested three different fiber samples: one “wet”, one “dry” and one with an intermediate “medium” OH content. The RIA of the three samples was measured in the 400–900 nm (~3 eV to ~1.4 eV) spectral range during and after an X-ray irradiation at a dose rate of 6 Gy(SiO2) s−1 up to a total accumulated dose of 300 kGy(SiO2). Furthermore, we evaluated the H2-pre-loading efficiency in the medium OH sample to permanently improve both its intrinsic losses and radiation response in the visible domain. Finally, the spectral decomposition of the various RIA responses allows us to better understand the basic mechanisms related to the point defects causing the excess of optical losses. Particularly, it reveals the relationship between the initial OH groups content and the generation of non-bridging oxygen hole centers (NBOHCs). Moreover, the presence of hydroxyl groups also affects the contribution from other intrinsic defects such as the self-trapped holes (STHs) to the RIA in this spectral domain.

Radiation Effects on Pure Silica Core Optical Fibers by γ-Rays: Relation between 2 eV Band and Non-Bridging Oxygen Hole Centers

1986 ◽  
Vol 25 (Part 1, No. 3) ◽  
pp. 464-468 ◽  
Author(s):  
Kaya Nagasawa ◽  
Yutaka Hoshi ◽  
Yoshimichi Ohki ◽  
Kichinosuke Yahagi
Keyword(s):  
Optical Fibers ◽  
Radiation Effects ◽  
Pure Silica ◽  
Oxygen Hole ◽  
Γ Rays ◽  
Silica Core ◽  
Hole Centers

Radiation Effects on Aluminosilicate Optical Fibers: Spectral Investigations From the Ultraviolet to Near‐Infrared Domains

2018 ◽  
Vol 216 (3) ◽  
pp. 1800485 ◽  
Author(s):  
Antonino Alessi ◽  
Angela Guttilla ◽  
Sylvain Girard ◽  
Simonpietro Agnello ◽  
Marco Cannas ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Radiation Effects ◽  
Near Infrared

Comparative Study of Pulsed X-Ray and$gamma$-Ray Radiation-Induced Effects in Pure-Silica-Core Optical Fibers

2006 ◽  
Vol 53 (4) ◽  
pp. 1756-1763 ◽  
Author(s):  
S. Girard ◽  
B. Brichard ◽  
J. Baggio ◽  
F. Berghmans ◽  
M. Decre
Keyword(s):  
Comparative Study ◽  
Optical Fibers ◽  
Gamma Ray ◽  
X Ray ◽  
Pure Silica ◽  
Radiation Induced ◽  
Silica Core

scholarly journals Water Adsorption Properties of Free and Dehydrated β-Cyclodextrin Studied by near Infrared Spectroscopy and Gravimetry

2016 ◽  
Vol 689 ◽  
pp. 143-147 ◽  
Author(s):  
Alfred A. Christy
Keyword(s):  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Water Adsorption ◽  
Near Infrared ◽  
Adsorption Properties ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Near Infrared Spectra ◽  
Adsorption Of Water

β-cyclodextrin, like other carbohydrates has a tendency to adsorb water molecules and the properties are attributed to the hydroxyl groups in the molecules. β-cyclodextrin, the cyclic oligomer of glucose has a hydrophobic interior and hydrophilic exterior. The cyclic structure favours the formation of hydrogen bonds between the OH groups on the adjacent glucose units and affects the formation of hydrogen bonds with water molecules. The hydoxyl groups engaged in hydrogen bondings can be eliminated at high temperatures and the adsorption properties of the dehydrated β-cyclodextrin will depend on the new functional groups formed. The aim of the report is to discuss the issue of the water adsorption properties of free and dehydrated β-cyclodextrin. Dry β-cyclodextrin and dehydrated β-cyclodextrin at temperatures 250, 300 and 350 °C were allowed to adsorb water from a humidity controlled air environmennt and the evolving near infrared spectra were measured using a near infrared spectrometer equipped with a transflectance accessory. The near infrared spectra in the region 10,000-4000 cm-1 and their second and fourth derivative profiles were used in studying the variation in the adsorption characteristics of dehydrated β-cyclodextrin. The results of the analyses show that the adsorption of water by β-cyclodextrin decreses at 300 °C compared to 200 and 250 °C. Dehydration forms more of the ethereal type-O-bonds in the molecule and explains the decrease in the water molecular adsorption at higher dehydration temperatures.

scholarly journals Active Compensation of Radiation Effects on Optical Fibers for Sensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8193
Author(s):  
Sohel Rana ◽  
Austin Fleming ◽  
Nirmala Kandadai ◽  
Harish Subbaraman
Keyword(s):  
Optical Fibers ◽  
Radiation Effects ◽  
Accurate Determination ◽  
Radiation Environment ◽  
Physical Parameters ◽  
Air Cavity ◽  
Sensing Applications ◽  
Fabry Perot ◽  
Radiation Induced

Neutron and gamma irradiation is known to compact silica, resulting in macroscopic changes in refractive index (RI) and geometric structure. The change in RI and linear compaction in a radiation environment is caused by three well-known mechanisms: (i) radiation-induced attenuation (RIA), (ii) radiation-induced compaction (RIC), and (iii) radiation-induced emission (RIE). These macroscopic changes induce errors in monitoring physical parameters such as temperature, pressure, and strain in optical fiber-based sensors, which limit their application in radiation environments. We present a cascaded Fabry–Perot interferometer (FPI) technique to measure macroscopic properties, such as radiation-induced change in RI and length compaction in real time to actively account for sensor drift. The proposed cascaded FPI consists of two cavities: the first cavity is an air cavity, and the second is a silica cavity. The length compaction from the air cavity is used to deduce the RI change within the silica cavity. We utilize fast Fourier transform (FFT) algorithm and two bandpass filters for the signal extraction of each cavity. Inclusion of such a simple cascaded FPI structure will enable accurate determination of physical parameters under the test.

Quantitative Analysis of Hydrogen Bonding in Poly(4-Vinylphenol) Blends Using near Infrared Spectroscopy

2003 ◽  
Vol 11 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Haijun Cai ◽  
Josée Brisson
Keyword(s):  
Hydrogen Bonding ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Weight Fraction ◽  
Hydroxyl Groups ◽  
Absorption Coefficients ◽  
Oh Groups ◽  
Refinement Method ◽  
Poly Ethylene ◽  
Vinyl Phenol

Quantitative evaluation of hydrogen bonding of poly(4-vinyl phenol)/poly(ethylene oxide) PVPh/PEO blends was conducted using Fourier transform near infrared (FT-NIR) spectroscopy. Absorption coefficients of the free ( aF), intra- (PVPh–PVPh) ( aA) and inter-associated (PVPh–PEO) hydroxyl groups ( aI) were estimated. Two sets of approximations were tested, including adopting a least-squares refinement method to calculate absorption coefficients from all NIR spectra or using a literature value for aF. Each set of absorption coefficients thus estimated were used to determine hydroxyl concentration for the free and hydrogen-bonded hydroxyl overtone bands in the blends. A comparison is made among the resultant concentrations of the free, intra- and inter-associated hydroxyl groups. The concentration of free hydroxyl groups markedly decreases with PEO percentage, and that of intra-associated hydroxyl remains almost constant. Concentration for the inter-associated hydroxyl groups in the blends increases very slowly above 0.2 PEO weight fraction. When concentration of OH groups is reported per PVPh chain, FT-NIR measurements show a broad maximum in the number of interchain hydrogen bonds. This result can be used to explain partially previous orientation behaviour observed for PVPh/PEO blends.

Radiation-Induced Absorption of Light in Undoped-Silica-Core Optical Fibers in the Near-Infrared Range: Effect of Drawing Conditions

2019 ◽  
Vol 46 (11) ◽  
pp. 340-343 ◽  
Author(s):  
P. F. Kashaykin ◽  
A. L. Tomashuk ◽  
M. Yu. Salgansky ◽  
N. N. Vechkanov ◽  
A. N. Guryanov ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Near Infrared ◽  
Infrared Range ◽  
Range Effect ◽  
Induced Absorption ◽  
Absorption Of Light ◽  
Radiation Induced ◽  
Silica Core ◽  
Near Infrared Range
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