UV Photoluminescence of Alumino-Germano-Silicate Glass Optical Fiber Incorporated with Gd₂O₃ Nano-Particles Upon Illumination of Xenon-Lamp

Alumino-germano-silicate glass optical fiber incorporated with Gd₂O₃ nano-particles (NPs) was developed by using the modified chemical vapor deposition and the drawing process. The formation of spherical Gd₂O₃ NPs in the fiber core with average diameter of 10.8 nm was confirmed by the TEM. The distinct absorption peaks in the fiber preform appearing in the UV region at 205, 247, 253, 274, and 312 nm were due to the incorporated Gd₂O₃ NPs via reorganization of the seven 4f electrons into various multiplets of Gd ions. In the case of the optical fiber obtained by drawing of the preform at high temperature about 2150 °C, absorption peaks due to Gd₂O₃ NPs were found to appear at 383 and 455 nm, which were red-shifted from 274 and 312 nm of the preform, respectively, and it may be due to increase in the size of Gd₂O₃ NPs after the drawing process. To investigate the photoluminescence (PL) property for UV sensor applications, the PL of the fiber was obtained by illumination of the Xenon-lamp. A PL band appeared in the wavelength band from 370 nm to 450 nm, centering at about 400 nm, which can be attributed to the presence of Gd₂O₃ NPs embedded in the fiber core. It was also found that the PL intensity at 400 nm showed linear dependence with the excitation power from 0 to 400 W.