1997 Fiscal Year Final Research Report Summary
Design of high gain optical Amplifier materials by control of 4f erectronic transition probability of rare earth doped glasses
| Project/Area Number |
08650989
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
無機工業化学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HANADA Teiichi Kyoto University, Faculty of Integrated Human Studies, Professor, 総合人間学部, 教授 (50111935)
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| Co-Investigator(Kenkyū-buntansha) |
TANABE Setsuhisa Kyoto University, Faculty of Integrated Human Studies, Assist.Prof., 総合人間学部, 助手 (20222119)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Rare earth / Glass / Optical amplifier / Optical telecommunication / 4f electrons / Optical fiber |
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| Research Abstract |
In order to develop the glass materials for optical amplifiers at 1.5mum and 1.3mum wavelengths, which are used in fiber telecommunications, Er^<3+>, Pr^<3+>, or Dy^<3+> ions were doped in several glasses and their host dependence of optical properties were investigated. Firstly the Judd-Ofelt intensity parameters, local structure and 1.5mum luminescence characteristics of Er^<3+> ions were investigated in the aluminosilicate glasses with various aluminum contents. Radiative decay rate from ^4I_<13/2> level was determined by Judd-Ofelt analyzes and nonradiative decay rate was obtained combined with the lifetime measurement. With increasing Al_2O_3 content the multiphonon decay rate decreased, which could be explained by the decrease of electron-phonon coupling strength observed in the phonon sideband spectra, whereas the emission probability of ^4I_<13/2>*^4I_<15/2> increased Accordingly the quantum efficiency of 1.5mum emission were enhanced from 70% to almost 90%. The results are dis
… More
cussed in terms of the change in the local structure and orbital electron density of Er^<3+> ions with the structural evolution of the glass.
Concentration and temperature dependences of fluorescence of Pr^<3+> : ^1G_4*^<>H_5 and Yb^<3+> : ^2F_<5/2>*^2F_<7/2> were investigated in tellurite glasses doped with up to 6mol% Yb_2O_3. By 970nm pumping, the 1.3mum emission of Pr^<3+> was sensitized.
The lifetime obtained by 1.02mum emission from the Yb^<3+>ions at room temprature was insensitive to the Yb_2O_3 concentration in singly doped glasses. However, the Yb-life-time showed strong concentration quenching with the presence of only 0.1mol% Pr_2O_3. The energy transfer efficiency from Yb to Pr in a codoped glass was found to be more than 90% even in the glass of[Yb]/[Pr]>100. The Yb-lifetime in singly doped glass increased and that in codoped glass decreased with increasing temperature. These results can be explained by assuming rapid energy migration between Yb ions and promotion of Yb^<3+>・^2F_<5/2>*Pr^<3+> : ^1G_4 transfer at higher temperature. Less
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