Silicon Hydride Formation in Co-60 Irradiated Optical Fibers

1989 ◽  
Vol 152 ◽  
Author(s):  
Bruce D. Evans
Keyword(s):  
Oxygen Vacancy ◽  
Optical Fibers ◽  
Near Infrared ◽  
Silicon Hydride ◽  
Hydride Formation ◽  
Pure Silica ◽  
Optical Attenuation ◽  
Silica Fibers ◽  
Radiolytic Process ◽  
Induced Changes

ABSTRACTDoping with hydrogen is shown to reduce the sensitivity of optical fibers to form optical attenuation bands as a result of ionizing radiation and to increase the recovery rate in the near infrared after the exposure. In this case silicon hydride is shown to form in low-OH, pure silica fibers upon Co-60 irradiation. The ratio of radiolytically induced changes in silicon hydride to silicon hydroxide is estimated to be greater than ten. The more numerous radiolytic formation of SiH species implies the participation of oxygen vacancy type defects in the radiolytic process.

scholarly journals Dependence of optical attenuation on radiation wavelength and waveguide geometry in copper-coated optical fibers

2020 ◽  
Vol 238 ◽  
pp. 11013
Author(s):  
Pavel Cherpak ◽  
Renat Shaidullin ◽  
Oleg Ryabushkin
Keyword(s):  
Optical Fibers ◽  
Near Infrared ◽  
Optical Loss ◽  
Single Mode ◽  
Optical Losses ◽  
Radiation Losses ◽  
Optical Attenuation ◽  
Novel Approach ◽  
Laser Sources

We demonstrate a novel approach to the determination of optical loss coefficients in metal-coated fibers in a 0.4-1.9 μm wavelength range. It is based on measuring the change of temperature-dependent electrical resistance of the metal coating caused by laser radiation transmitted through the fiber. A number of single-mode and multimode metallized fibers were investigated using several laser sources operating in visible and near infrared ranges. The spectral dependencies of optical losses of copper-coated fibers were experimentally obtained. The region that corresponds to the minimum optical losses is located near 1 μm wavelength. The increase of radiation losses in 1.5-1.9 μm region is much steeper compared to polymer-coated fibers.

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.

In-Vessel Inspection Probing Technique Using Optical Fibers Under High Radiation Dose

2014 ◽  
Author(s):  
Chikara Ito ◽  
Hiroyuki Naito ◽  
Hironori Ohba ◽  
Morihisa Saeki ◽  
Keisuke Ito ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Nuclear Power ◽  
Near Infrared ◽  
Gamma Ray ◽  
Pressure Vessels ◽  
High Radiation ◽  
Remote Imaging ◽  
Pure Silica ◽  
Radiation Resistant

A high-radiation resistant optical fiber has been developed in order to investigate the interiors of the reactor pressure vessels and the primary containment vessels of the Fukushima Daiichi Nuclear Power Station. The radiation resistance of an optical fiber was improved by increasing the amount of hydroxyl up to 1000 ppm in pure silica fiber. We have tried to apply the optical fiber for remote imaging technique by means of fiberscope. The improved image fiber consists of common cladding and a large number of fiber cores made from pure silica that contains 1000 ppm hydroxyl. The transmissive rate of an infrared image was not affected after the irradiation of 1 MGy. The radiation resistant optical fiber is available for remote ultimate analysis by laser induced breakdown spectroscopy (LIBS) in order to identify whether a material is fuel debris or not. We have developed the fiber-coupled LIBS system to detect plasma emission efficiently in near-infrared region. In addition, we have performed a gamma ray dose rate measurement using an optical fiber of which scintillator is attached to the tip. As a result, the concept of applicability of a probing system using the high-radiation resistant optical fibers has been confirmed.

In situ near infrared evanescent wave examination of surfactant adsorption on silica optical fibers

1994 ◽  
Vol 2 (3) ◽  
pp. 187-197 ◽  
Author(s):  
A.K. Liao ◽  
W.M. Cross ◽  
R.M. Winter ◽  
J.J. Kellar
Keyword(s):  
Optical Fibers ◽  
Evanescent Wave ◽  
Near Infrared ◽  
Surfactant Adsorption
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