Optical properties of Nd3+-doped silica fibers obtained by sol-gel method

The Nd3+-doped sol-gel silica fiber of clad-polymer type, 125 mu m in diameter, was pulled from the preform with concentration of active ions of 0.03 mol.%. The optical properties of such a fiber were investigated and compared to monolithic samples. The attenuation factor for this fiber was determined at 1.08 mu m to be 90 dB/km. The difference in emission spectra between neodymium-doped sol-gel silica bulk samples and fibers manifesting in a significant shifting of the peak emission of F-4(3/2)-->I-4(11/2) transition was observed. The fluorescence of Nd3+ silica gel fiber was measured as a function of length of fiber and excitation power. It was found that the fluorescence intensities and lifetimes were slightly dependent on fiber length. Moreover it was noted that the intensity of fluorescence increased linearly with power. (C) 2000 Elsevier Science S.A. All rights reserved.