Ultraviolet-induced permanent Bragg gratings in cerium-doped ZBLAN glasses or optical fibers.
A holographic method was used to write refractive-index gratings in ZBLAN fluoroziroconate glasses or fibers doped by a Ce concentration of 5000 or 10,000 parts-in-10(6) weight. Direct pumping of the (2)F(5/2)-5d transitions of Ce(3+) ions near 245 nm resulted in a change in the refractive index. The photoinduced change partly recovered on a time scale of several hours at room temperature. The remaining change in the refractive index looked stable on a time scale of a month. This permanent change reaches 2 x 10(-5) at 1560 nm.
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Taunay
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Niay
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Bernage
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Xie
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Poignant
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Boj
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Delevaque
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Monerie