RARE-EARTH CONCENTRATION AND LOCALIZATION IN ND3+ AND ER3+ DOPED FIBER AMPLIFIERS

In the process of optimising the gain for rare earth doped fibre amplifiers, we have studied the modification of the fluorescence properties with composition of the host core glass and with rare earth concentration. We propose an original method for the determination of the effective rare earth concentration based on the Judd-Ofelt theory taking account of the properties of the waveguide. An illustration of this method is given in the case of Nd3+ doped fibres. We report measurements of anomalous spatial distributions of the rare earth along the diameter of an erbium-doped preform. Moreover fluorescence dynamics are shown to be sensitive to the local environment of the rare earth, with the decay time varying significantly with the nature of the chemical dopant Al2O3 or GeO2. © 1990.