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6. GLASS MATERIALS FOR OPTICAL FIBERS

Author

Ivan Kasik, Vlastimil Matejec, Hayer Milos, Kamradek Michal, Podrazky Ondrej, Mrazek Jan, Peterka Pavel, and Honzatko Pavel

Subjects
optical fibers, silica glass, mcvd, fiber lasers, Clay industries. Ceramics. Glass, TP785-869
Abstract

Optical fibers represent the key component of modern optical telecommunication networks. Such fibers are based on silica glass of high purity usually modified with several percent of glassforming oxides such as GeO₂ and P₂O₅. These materials with minimum optical losses around 1.5 μm are transparent up to ∼2 μm. In this paper, the attention is focused on silica glass materials doped with ions of rare-earth elemens for fiber lasers and fiber amplifiers. Since rare earths cause phase separation only in small amount incorporated into silica glass, ternary systems containing P₂O₅ or Al₂O₃ have been investigated. Latest results in GeO₂-based glasses transparent in mid infrared region are also presented.

Published
2019
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7. Preparation and characterization of highly thulium- and alumina-doped optical fibers for single-frequency fiber lasers

Author

Honzatko, Pavel, Dhar, Anirban, Kasik, Ivan, Podrazky, Ondrej, Matejec, Vlastimil, Peterka, Pavel, Blanc, Wilfried, and Dussardier, Bernard

Subjects
Physics - Optics
Abstract

Thulium-doped fibers suitable for core-pumped single-frequency lasers were fabricated by the modified chemical vapor deposition (MCVD) method. Refractive index profile, doping profile and spectral absorption was measured. High doping concentration of thulium ions should be achieved to allow for high absorption of light at a pump wavelength while the thulium ions clustering should be avoided to prevent the cooperative upconversion and quenching processes. The fabricated fibers featured pump absorption up to 70dB/m at a pump wavelength of 1611nm. The single-frequency master oscillator with a resonator composed of a pair of fiber Bragg gratings and a thulium-doped fiber was demonstrated with predominantly single ended operation. We achieved a slope efficiency of 22% and a threshold of 22mW at a lasing wavelength of 1944nm.

Published
2012
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9. GLASS MATERIALS FOR OPTICAL FIBERS

Author

Kamradek Michal, Podrazky Ondrej, Hayer Milos, Honzatko Pavel, Mrazek Jan, Vlastimil Matejec, Ivan Kašík, and Peterka Pavel

Subjects
optical fibers, Optical fiber, Materials science, General Chemical Engineering, mcvd, Glass material, fiber lasers, Analytical Chemistry, law.invention, lcsh:TP785-869, silica glass, lcsh:Clay industries. Ceramics. Glass, law, Materials Chemistry, Ceramics and Composites, Physical and Theoretical Chemistry, Composite material
Abstract

Optical fibers represent the key component of modern optical telecommunication networks. Such fibers are based on silica glass of high purity usually modified with several percent of glassforming oxides such as GeO₂ and P₂O₅. These materials with minimum optical losses around 1.5 μm are transparent up to ∼2 μm. In this paper, the attention is focused on silica glass materials doped with ions of rare-earth elemens for fiber lasers and fiber amplifiers. Since rare earths cause phase separation only in small amount incorporated into silica glass, ternary systems containing P₂O₅ or Al₂O₃ have been investigated. Latest results in GeO₂-based glasses transparent in mid infrared region are also presented.

Published
2019

26. Flat metal-dielectric grating with 100% retro-diffraction efficiency: rigorous theory.

Author

Honzatko, Pavel and Čtyroký, Jiří

Subjects
*APPROXIMATION theory, *ELECTROMAGNETIC theory, *DIFFRACTION gratings, *TRANSVERSAL lines
Abstract

We have recently designed a new type of a flat metal-dielectric grating which is supposed to replace blazed diffraction gratings, providing very high −1st reflected diffraction order efficiency within a broad wavelength band, high durability, and relative ease of fabrication. In this communication we present a rigorous electromagnetic theory of the grating in the approximation of infinitely thin perfect metal and show that the properly designed grating can reach 100% diffraction efficiency in the Littrow configuration for either transversal electric (TE or s) or transversal magnetic (TM or p) polarizations. Properties of the grating are analysed and discussed in detail. [ABSTRACT FROM AUTHOR]

Published
2021
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38. Thulium-doped silica fibers with enhanced 3H4 level lifetime for fiber lasers and amplifiers

Author

Peterka, Pavel, Dussardier, Bernard, Blanc, Wilfried, Kašík, Ivan, Honzatko, Pavel, Institute of Photonics and Electronics of the Czech Academy of Sciences (UFE / CAS), Czech Academy of Sciences [Prague] (CAS), Laboratoire de physique de la matière condensée (LPMC), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics]
Abstract

International audience; Thulium-doped fibers are renowned for their applications in high power fiber lasers at around 2 µm. It is despite the low quantum conversion efficiency of 3F4 level in thulium doped silica fibers, which is about 10% compared to ~100% quantum conversion efficiency of the ytterbium- and erbium-doped fibers, at around 1 µm and 1.5 µm, respectively. The lower quantum conversion efficiency increases the 2 µm laser threshold but has almost no effect on the laser slope efficiency. Indeed, kW-class thulium-doped fiber lasers have been demonstrated recently. Quantum conversion efficiency of the 3H4 level in non-modified silica fibers is much lower than that of 3F4 level, only about 2% and therefore most of the applications of laser transitions originating from 3H4 level are hindered by the lack of reliable low-phonon fiber host. We review of our contributions towards the comprehension and improvement of the spectroscopic properties of thulium ions doped into silica. We show potential of the developed thuliumdoped fibers with enhanced 3H4 level lifetime for applications in fiber lasers around 810 nm and in fiber amplifiers for communication S-band (1460-1530 nm).

Published
2012

41. Single-frequency fiber laser based on a fiber ring resonator filter tunable in a broad range from 1023??nm to 1107??nm

Author

Honzatko, Pavel, Baravets, Yauhen, and Myakalwar, Ashwin Kumar

Abstract

We present a broadly tunable single-frequency ytterbium-doped fiber laser. Its broadband tunability is made possible by low resonator losses. The wavelength is determined by a grating filter, while the single-frequency regime is achieved by filtering the longitudinal modes in a fiber ring resonance filter. We obtained a tuning range from 1023 nm to 1107 nm. A feedback loop driving a fiber stretcher actuated by a piezo-element prevents mode hopping. Based on the coherent delayed self-heterodyne interferometry, the laser linewidth is estimated to be 600 Hz with feedback open and 11.7 kHz with feedback closed.

Published
2018

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