The Experts below are selected from a list of 8118 Experts worldwide ranked by ideXlab platform
Mihailov, Stephen J. - One of the best experts on this subject based on the ideXlab platform.
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Birefringent \u3c0-phase-shifted Fiber bragg gratings for sensing at 1000 \ub0C fabricated using an infrared femtosecond laser and a phase mask
IEEE, 2018Co-Authors: Hnatovsky Cyril, Grobnic Dan, Mihailov, Stephen J.Abstract:Birefringent \u3c0-phase-shifted Bragg gratings for multi-parameter sensing at temperatures ~1000 \ub0C are written inside a standard single mode Silica Optical Fiber (SMF-28) with infrared femtosecond pulses and a special phase mask one half of which is shifted with respect to the other by 5/4 of the mask period. The birefringence is caused by the presence of light-induced sub-wavelength periodic planar nanostructures in the Fiber core, whose orientation is controlled by the laser polarization, and is maximized when the laser pulse polarization is aligned perpendicular to the Fiber core. The birefringence can reach ~4.2 7 10 -4 at room temperature at the 1.5 7 10 -4 level after 100 h annealing at 1000 \ub0C. Erasure and rewriting of the planar nanostructures inside Fiber Bragg gratings by changing the laser pulse polarization is demonstrated.Peer reviewed: YesNRC publication: Ye
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High-temperature stable \u3c0-phase-shifted Fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask
OSA, 2018Co-Authors: Hnatovsky Cyril, Grobnic Dan, Mihailov, Stephen J.Abstract:Type II \u3c0-phase-shifted Bragg gratings stable up to ~1000\ub0C are written inside a standard single mode Silica Optical Fiber (SMF-28) with infrared femtosecond pulses and a special phase mask. Inscription through the protective polyimide Fiber coating is also demonstrated. The birefringence of the Bragg gratings and, as a result, the polarization dependence of their spectra are strongly affected by the femtosecond laser polarization. Using optimized writing conditions, the full width at half maximum of the \u3c0-phase-shifted passband feature can be ~30 pm in transmission, while the polarization-dependent shift of its central wavelength can be less than 8 pm, for a 7 mm long grating structure. This makes such gratings a unique tool for high-resolution measurements of temperature, load and vibration in extreme temperature environments.Peer reviewed: YesNRC publication: Ye
Gangding Peng - One of the best experts on this subject based on the ideXlab platform.
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fluorine passivation of odc defects in amorphous germanium dioxide
Journal of Non-crystalline Solids, 2020Co-Authors: Xiaoning Guan, Ru Zhang, Baonan Jia, Bo Zhou, Ling Fan, Gang Liu, You Wang, Gangding PengAbstract:Abstract We present first-principle calculations on the interaction of atomic and molecular fluorine with germanium oxygen-deficient center (GODC) in amorphous germanium dioxide (a-GeO2). The interaction of atomic fluorine with GODC in a-GeO2 results in the formation of Ge-F-Ge and GE′ center. The reaction pathways and the energy barriers have been investigated to understand the formation of the fully passivated configurations which are obtained by the interaction of molecular fluorine with GODC in a-GeO2. Our results indicate that the GODC defects prefer to be passivated by the molecular fluorine. It is found that in the near-ultraviolet region, the Optical absorption of the fully passivated configurations is significantly reduced by doping of fluorine. These results help to better understand the mechanism of how atomic and molecular fluorine passivate GODC defects and optimize the Optical characteristics in F/Ge co-doped Silica Optical Fiber.
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Silica Optical Fiber drawn from 3d printed preforms
Optics Letters, 2019Co-Authors: Yushi Chu, Yanhua Luo, Joh Canning, Yua Tia, Kevi Cook, Jianzhong Zhang, Gangding PengAbstract:Silica Optical Fiber was drawn from a three-dimensional printed preform. Both single mode and multimode Fibers are reported. The results demonstrate additive manufacturing of glass Optical Fibers and its potential to disrupt traditional Optical Fiber fabrication. It opens up Fiber designs for novel applications hitherto not possible.
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electronic and luminescence characteristics of interstitial bi0 atom in bismuth doped Silica Optical Fiber
Journal of Luminescence, 2019Co-Authors: Jie Zhang, Xiaoning Guan, Baonan Jia, Zhixing Peng, Binbin Yan, Lihong Han, Zixuan Guan, Gangding PengAbstract:Abstract We report first-principles calculations of cluster Silica with and without interstitial Bi0 atom. The size and radial distance of “Si-O-Si” rings are considered to study the equilibrium position of interstitial Bi0 atom in Bi-doped Silica Optical Fiber. Our results reveal that the interstitial Bi0 atom is most likely to stay around ~ 2 A from the center of 6-membered rings. By comparing the transition energy levels with Bi0 atomic spectral data, we find that the transition 2D3/2(1) → 4S3/2 of interstitial Bi0 atom leads to the NIR emission estimated as ~ 1265 nm in Bi-doped Silica Optical Fiber. Our methods will be effective to confirm bismuth-active centers for different valence states of Bi atom.
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near ir luminescence characteristics of monovalent bismuth in bi doped pure Silica Optical Fiber first principle study
Journal of Luminescence, 2018Co-Authors: Baonan Jia, You Wang, Zhixing Peng, Binbin Yan, Bin Yang, Gangding PengAbstract:Abstract Monovalent bismuth-related centers in pure Silica Optical Fiber are calculated by using first-principle methods. Transition energy levels of three different structural models are investigated on the basis of the time-dependent density functional theory (TDDFT). Compared with the experimental data of near-IR luminescence, our calculated results suggested that luminescence near 1492 nm is likely caused by SiOBi configuration; and luminescence at 1147 nm and 1403 nm may be caused by interstitial Bi2O molecule. Moreover, SiBi configuration, which might be the origin of the luminescence near 1629 nm, is difficult to directly form because of its relatively high formation energy.
Hnatovsky Cyril - One of the best experts on this subject based on the ideXlab platform.
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Birefringent \u3c0-phase-shifted Fiber bragg gratings for sensing at 1000 \ub0C fabricated using an infrared femtosecond laser and a phase mask
IEEE, 2018Co-Authors: Hnatovsky Cyril, Grobnic Dan, Mihailov, Stephen J.Abstract:Birefringent \u3c0-phase-shifted Bragg gratings for multi-parameter sensing at temperatures ~1000 \ub0C are written inside a standard single mode Silica Optical Fiber (SMF-28) with infrared femtosecond pulses and a special phase mask one half of which is shifted with respect to the other by 5/4 of the mask period. The birefringence is caused by the presence of light-induced sub-wavelength periodic planar nanostructures in the Fiber core, whose orientation is controlled by the laser polarization, and is maximized when the laser pulse polarization is aligned perpendicular to the Fiber core. The birefringence can reach ~4.2 7 10 -4 at room temperature at the 1.5 7 10 -4 level after 100 h annealing at 1000 \ub0C. Erasure and rewriting of the planar nanostructures inside Fiber Bragg gratings by changing the laser pulse polarization is demonstrated.Peer reviewed: YesNRC publication: Ye
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High-temperature stable \u3c0-phase-shifted Fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask
OSA, 2018Co-Authors: Hnatovsky Cyril, Grobnic Dan, Mihailov, Stephen J.Abstract:Type II \u3c0-phase-shifted Bragg gratings stable up to ~1000\ub0C are written inside a standard single mode Silica Optical Fiber (SMF-28) with infrared femtosecond pulses and a special phase mask. Inscription through the protective polyimide Fiber coating is also demonstrated. The birefringence of the Bragg gratings and, as a result, the polarization dependence of their spectra are strongly affected by the femtosecond laser polarization. Using optimized writing conditions, the full width at half maximum of the \u3c0-phase-shifted passband feature can be ~30 pm in transmission, while the polarization-dependent shift of its central wavelength can be less than 8 pm, for a 7 mm long grating structure. This makes such gratings a unique tool for high-resolution measurements of temperature, load and vibration in extreme temperature environments.Peer reviewed: YesNRC publication: Ye
Alexandre De Almeida Prado Pohl - One of the best experts on this subject based on the ideXlab platform.
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Time Analysis of the Wavelength Shift in Fiber Bragg Gratings
Journal of Lightwave Technology, 2007Co-Authors: Paulo De Tarso Neves, Alexandre De Almeida Prado PohlAbstract:This paper presents the time analysis of the Bragg wavelength shift in Fiber gratings based on the elastodynamics theory. The model is valuable for estimating an upper limit for the tuning speed when traction forces are applied to the free end of the grating. A comparison between the single-mode Silica Optical Fiber and polymer Optical Fiber is performed, showing the differences in time response, tuning speed, and Bragg wavelength shift when the same longitudinal load is applied on both types of Fibers.
Benjamin John Eggleton - One of the best experts on this subject based on the ideXlab platform.
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Efficient coupling to chalcogenide glass photonic crystal waveguides via Silica Optical Fiber nanowires.
Optics express, 2006Co-Authors: Christian Grillet, Darren Freeman, Eric Magi, Cameron Smith, Steve Madden, Barry Luther-davies, David Moss, Benjamin John EggletonAbstract:We demonstrate highly efficient evanescent coupling between a highly nonlinear chalcogenide glass two dimensional photonic crystal waveguide and a Silica Fiber nanowire. We achieve 98% insertion efficiency to the fundamental photonic crystal waveguide mode with a 3dB coupling bandwidth of 12nm, in good agreement with theory. This scheme provides a promising platform to realize low power nanocavity based all-Optical switching and logic functions.