Thermal stability and spectroscopic properties of Er3+-doped niobium tellurite glasses for broadband amplifiers

Three Er3+-doped tellurite glasses with compositions of 70TeO(2)-30ZnO, 70TeO(2)-20ZnO-10Nb(2)O(5) and 70TeO(2)-20ZnO-5BaO-5Nb(2)O(5) have been investigated for developing fiber and planar broadband amplifiers and lasers. The optical spectroscopic properties and thermal stability of Er3+-doped tellurite glasses have been discussed. The results show that the incorporation of Nb2O5 increases the thermal stability of Er3+-doped tellurite glasses significantly, Er3+-doped niobium tellurite glasses 70TeO(2)-20ZnO-10Nb(2)O(5) and 70TeO(2)-20ZnO-5BaO-5Nb(2)O(5) exhibit the good thermal stability (DeltaT > 150degreesC), the large emission cross-section (>10 x 10(-21) cm(2)) and broad full width at half maximum (similar to65 nm), will be preferable for broadband Er3+-doped fiber amplifiers. (C) 2004 Elsevier B.V. All rights reserved.

Characterization of Er3+-doped Na2O-WO3-TeO2 glass for ion-exchanged waveguide amplifiers and lasers

Er^(3+)-doped Na2O-WO3-TeO2 glass consistent with standard ion-exchange technology has been fabricated and characterized. The measured absorption and emission spectra of the glass were analyzed by the Judd-Ofelt and McCumber theories. The intensity parameters are Ω2 = 7.01

Assessing seasonal precipitation trends in India using parametric and non-parametric statistical techniques

This paper provides an insight into the long-term trends of the four seasonal and annual precipitations in various climatological regions and sub-regions in India. The trends were useful to investigate whether Indian seasonal rainfall is changing in terms of magnitude or location-wise. Trends were assessed over the period of 1954-2003 using parametric ordinary least square fits and non-parametric Mann-Kendall technique. The trend significance was tested at the 95% confidence level. Apart from the trends for individual climatological regions in India and the average for the whole of India, trends were also specifically determined for the possible smaller geographical areas in order to understand how different the trends would be from the bigger spatial scales. The smaller geographical regions consist of the whole southwestern continental state of Kerala. It was shown that there are decreasing trends in the spring and monsoon rainfall and increasing trends in the autumn and winter rainfalls. These changes are not always homogeneous over various regions, even in the very short scales implying a careful regional analysis would be necessary for drawing conclusions regarding agro-ecological or other local projects requiring change in rainfall information. Furthermore, the differences between the trend magnitudes and directions from the two different methods are significantly small and fall well within the significance limit for all the cases investigated in Indian regions (except where noted). © 2010 Springer-Verlag.