Abstract Using transmission electron microscopy (TEM) and x-ray diffraction analysis, we have studied the structural and morphological evolution of highly Er/Yb co-doped Al2O3 films in the temperature range from $600\,^{\circ}\mkern-1mu$C--900$\,^{\circ}\mkern-1mu$C. By comparison with TEM observation, the annealing behaviours of photoluminescence (PL) emission and optical loss were found to have relation to the structure and morphology. The increase of PL intensity and optical loss above 800$\,^{\circ}\mkern-1mu$C might result from the crystallization of amorphous Al2O3 films. Based on the study on the structure and morphology, a rate equation propagation model of a multilevel system was used to calculate the optical gains of Er-doped Al2O3 planar waveguide amplifiers involving the variation of PL efficiency and optical loss with annealing temperature. It was found that the amplifiers had an optimized optical gain at the temperature corresponding to the minimum of optical loss, rather than at the temperature corresponding to the maximum of PL efficiency, suggesting that the optical loss is a key factor for determining the optical gain of an Er-doped Al2O3 planar waveguide amplifier.
Received: 07 November 2005
Revised: 23 March 2006
Accepted manuscript online:
Fund: Project supported by the National
Natural Science Foundation of China (Grant No 50240420656).
Cite this article:
Tan Na(谭娜) and Zhang Qing-Yu(张庆瑜) Annealing behaviour of structure and morphology and its effects on the optical gain of Er3+/Yb3+ co-doped Al2O3 planar waveguide amplifier 2006 Chinese Physics 15 2165
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