EFFECT OF THE ANNEALING PROCESS ON ACTIVE PROPERTIES OF PROTON-EXCHANGED OPTICAL WAVEGUIDES IN ERBIUM-DOPED LITHIUM NIOBATE

The effect of annealing on the resultant chemical composition of the Annealed Proton Exchange layers and their optical properties was studied, with emphasis on their potential active function. The samples were annealed at various conditions and characterised by nuclear analytic methods to investigat...

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Bibliographic Details
Published in:Ceramics (Praha) 2005-01, Vol.49 (2), p.86-90
Main Authors: Salavcova, L, Spirkova, J, Capek, P, Novotna, M, Vacik, J, Mackova, A, Kreissig, U
Format: Article
Language:English
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Summary:The effect of annealing on the resultant chemical composition of the Annealed Proton Exchange layers and their optical properties was studied, with emphasis on their potential active function. The samples were annealed at various conditions and characterised by nuclear analytic methods to investigate concentration profiles of the exchanged ions. The content of OH groups, which are undesirable in active waveguiding layers due to their effect on erbium excited state lifetimes shortening, was studied by IR absorption spectrometry. The waveguiding properties (number of guided modes, refractive index vs. depth profile) were measured by mode spectroscopy at 632.8 nm. Hydrogen introduced to the surface layers of LiNbO3 by proton exchange moved deeper into the substrate during annealing, thus lowering total refractive index increment. Consequently, the crystallographic phase of the exchanged layers changed towards the alpha-phase. The lowest amounts of OH groups were found when highest annealing temperatures were used. However, a limitation existed as temperatures above 400 C caused degradation of the waveguiding properties. 10 refs.
ISSN:0862-5468