NONDESTRUCTIVE CONCENTRATION MEASUREMENTS OF ERBIUM-DOPED ZBLAN FLUOROZIRCONATE GLASS

The non-destructive method proposed for the measurements of neodymium concentrations in laser materials has been extended to erbium-doped fl uorozirconate glass. It consists of comparing the intensity of a lumin escence signal from the rare-earth ions with the intensity of a Raman line from the host matrix, both measured in a single geometry under a microscope. The investigations have been performed in the erbium-doped core glass of ZBLAN preforms and multimode optical fibers (in the con centration range 0-5000 ppm.w). In standard use, the relative error in the results can be less than 12%. The method is punctual (a few mu m( 3)), and highly sensitive; therefore it seems to be particularly well adapted for measurements in preforms and in optical fibers.